WO1997011960A1

WO1997011960A1 - Antagonists of endothelin receptors

Info

Publication number: WO1997011960A1
Application number: PCT/EP1996/004063
Authority: WO
Inventors: Junichi Sakaki; Toshiki Murata; Yoko Yuumoto; Ikushi Nakamura; Toshikazu Okada
Original assignee: Japat Ltd.; Novartis Ag; Ciba-Geigy Japan Limited
Priority date: 1995-09-28
Filing date: 1996-09-17
Publication date: 1997-04-03
Also published as: JPH11512702A; ZA968093B; AU7130296A

Abstract

The present invention provides novel compounds represented by general formula (I), wherein (i) R1 represents 1,2,4-triazol-1-yl, R2 represents methyl or hydroxy, R3 represents methyl or hydroxy, and the asterix means that the chiral carbon atom to which said asterix is attached has the (D) or (D,L) configuration, or (ii) R1 represents isoxazol-5-yl, R2 is methyl, R3 is methyl, and the asterix means that the chiral carbon atom to which said asterix is attached has the (D) configuration; and salts thereof; processes for the manufacture, pharmaceutical compositions and the use of the compounds of formula (I) and salts thereof.

Description

ANTAGONISTS OF ENDOTHELIN RECEPTORS

BACKGROUND OF THE INVENTION

The present invention relates to novel compounds as antagonists of endothelin (ET) receptors, processes for their preparation, their use and pharmaceutical compositions.

ETs are a family of vasoactive peptides with 21 amino acid residues and two intramolecular disulfide bonds. They comprise ET-1 , the original ET isolated from the culture media of porcine endothelial cells, ET-2 and ET-3.

ETs, of which biosynthesis is enhanced by many biological and pathological factors, are widely distributed in both peripheral and brain tissues of mammalians, and elicit a number of biological responses by binding to at least two distinct ET receptor subtypes, ET_A and ET_B receptors.

ET receptors are present in cardiovascular, renal, hepatic and neural tissues. ET receptors are also found in the respiratory, gastro-intestinal, endocrine, central nervous and genito-urinary systems, the blood and blood forming organs, the sensory organs, and other tissues in the body.

ETs are the most potent and longest acting endogeneous constrictors of blood vessels identified to date. ETs also cause contraction of various non-vascular smooth muscles including the air-way, and the cardiac muscle. In addition, ETs are mitogenic ulcerogenic and pro-inflammatory. ETs have regulatory functions on hormone- or peptide- secretion, neurotransmission, ion-transport and metabolism.

SUMMARY OF THE INVENTION

The present invention provides novel compounds represented by the general formula I

wherein (i) R, represents 1 ,2,4-triazoM -yl, R₂ represents methyl or hydroxy, R₃ represents methyl or hydroxy, and the asterix means that the chiral carbon atom to which said asterix is attached has the (D) or (D,L) configuration, or (ii) Ri represents isoxazol-5-yl, R₂ is methyl, R₃ is methyl, and the asterix means that the chiral carbon atom to which said asterix is attached has the (D) configuration; and salts thereof; processes for the manufacture, pharmaceutical compositions and the use of the compounds of formula I and salts thereof.

All of the compounds of the present invention possess two or more chiral centers which may exist e.g. in the (D), (L), or (D,L) configuration which means that the corresponding structural features are derhved from corresponding (D), (L), or (D,L) amino acids. The compounds of the present invention exist in an essentially pure diasteromeric and enantiomerical form.

The compounds represented by the formula (I) are capable of forming pharma¬ ceutically acceptable acid addition salts and/or base addition salts. Pharmaceutically acceptable acid addition salts of the compounds (I) include those of inorganic acids, for example, hydrohalic acids such as hydrochloric acid, hydrodromic acid or hydroiodic acid, nitric acid, sulfuric acid, phosphoric acid; organic acids, for example, lower alkanoic acids such as formic acid, acetic acid, propionic acid, butylic acid, hydroxy acids such as lactic acid, citric acid or malic acid, dicarboxylic acids such as maleic acid or succinic acid, sulfonic acids, for example, lower alkanesulfonic acids such as methanesulfonic acid, or benzenesulfonic acid. Salts of the present compounds (I) with bases are, for example, those with bases, for example, inorganic bases such as ammonium hydroxide or metal hydroxide, such as lithium hydroxide, such as alkaline metal hydroxide such as sodium hydroxide, potassium hydroxide, alkaline earth metal hydroxide, such as calcium hydroxide; or those with organic bases, for example, amines, for example, mono-, di- or tri-lower alkylamines, such as mono- , di- or tri-methyl-amine or -ethyl-amine.

The general definitions used below, unless defined differently, have the following meanings:

The expression "lower" means that corresponding groups and compounds in each case in particular comprise not more than 7, preferably not more than 4, carbon atoms.

The term "lower alkyl" means an alkyl having 1 up to and including 7 carbon atoms, preferably 1 up to and including 4 carbon atoms, and for example, is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, straight or branched pentyl, straight or branched hexyl, or straight or branched heptyl.

Lower alkoxy is in particular d-C₇alkoxy and is, for example, methoxy, ethoxy, n- propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, tert-butyloxy and also includes corresponding pentyloxy, hexyloxy and heptyloxy radicals. C C₄aikoxy is preferred.

Lower alkylene is, for example, Cι-C₇alkylene, and is straight-chain or branched and is in particular methylene, ethylene, propylene and butylene and also 1 ,2-propylene, 2- methyl-1 ,3-propylene and 2,2-dimethyl-1 ,3-propylene. d-Csalkylene is preferred.

Halogen is in particular halogen of atomic number not more than 35, such as fluorine, chlorine or bromine, and also includes iodine.

Extensive pharmacological investigations have shown that the compounds I and their pharmaceutically acceptable salts, for example, have pronounced pharmaceutical, for example, endothelin receptor antagonistic, properties and a beneficial pharmacological profile. The compounds of the present invention bind to both the ET_A and ET_B receptors. Compared to prior aπ endothelin receptor antagonists, the compounds according to the present invention comprise at most two peptidic bonds. Furthermore, they are distinguished from prior art compounds not only by their unexpected and favorable stability as well as by the pharmacological profile.

The ET receptor antagonists of the present invention are useful for various human diseases caused by ETs, either directly or in concert with other factors. In particular, they are useful for various cardiovascular diseases such as cerebral and coronary vasospasm, cerebral and cardiac ischemia, subarachnoidal haemorrhage, various types of hypertension, pulmonary hypertention, cardiac failure, Raynand-syndrome, diabetes, benign prostatic hyperplasia, atherosclerosis or restenosis due to denudation following angioplasty.

The compounds of the present invention also provide a new therapeutic potential for asthma, renal failure, dialysis, glomerular injury, hepatic failure, stomach and duodenal ulcer, ulcus cruris, various brain dysfunctions including migraine and delayed neuronal death, various cancers including prostate cancer, and occular diseases, glaucoma in particular.

They are also useful to overcome the adverse effects of cyclosporin and can be used for endotoxin shock, or disseminated intravascular coagulation.

The compounds of the formula I and their pharmaceutically acceptable salts can therefore be used, for example, as pharmaceutical active ingredients which are employed, for example, for the treatment of various cardiovascular diseases such as cerebral and coronary vasospasm, cerebral and cardiac ischemia, subarachnoidal haemorrhage, various types of hypertension, pulmonary hypertention, cardiac failure, Raynand-syndrome, diabetes, benign prostatic hyperplasia, atherosclerosis or restenosis due to denudation following angioplasty and also for the treatment of asthma, renal failure, dialysis, glomerular injury, hepatic failure, stomach and duodenal ulcer, ulcus cruris, various brain dysfunctions including migraine and delayed neuronal death, various cancers including prostate cancer, and occular diseases, glaucoma in particular. The invention thus relates to the use of the compounds according to the invention and their pharmaceutically acceptable salts for the production of appropriate medicaments and to the therapeutic treatment of various cardiovascular diseases such as cerebral and coronary vasospasm, cerebral and cardiac ischemia, subarachnoidal haemorrhage, various types of hypertension, pulmonary hypertention, cardiac failure, Raynand-syndrome, diabetes, benign prostatic hyperplasia, atherosclerosis or restenosis due to denudation following angioplastyalso for the treatment of asthma, renal failure, dialysis, glomerular injury, hepatic failure, stomach and duodenal ulcer, ulcus cruris, various brain dysfunctions including migraine and delayed neuronal death, various cancers including prostate cancer, and occular diseases, glaucoma in particular. The industrial production of the active substances is also included in the production of the pharmaceuticals.

The invention relates in particular to compounds of the formula (la)

wherein R, represents 1 ,2,4-triazol-1 -yl or isoxazol-5-yl, and salts, especially pharmaceutically acceptable salts thereof.

The invention relates in particular to the novel compounds shown in the examples and to the methodes for their preparation described therein.

The invention relates to processes for the preparation of the compounds according to the invention. The preparation of compounds of the formula I or la, respectively, and their salts comprises, for example,

a) reacting a compound of formula (lia)

wherein R_{1 (} R₃ and the asterix are as definied above, or a salt or a reactive acid derivative thereof with a compound of formula (lib)

wherein R₂ is as defined above, or a salt thereof; or, b) for the manufacture of a compound of formula (I) or a salt thereof, wherein the asterix means that the chiral carbon atom to which said asterix is attached has the (D) configuration, separating a mixture of isomers of formula (I), wherein the asterix means that the chiral carbon atom to which said asterix is attached has the (D,L) configuration and isolating the desired isomer,

and, if desired, free functional groups in starting material of each variant, with the exception of those participating in the reaction, being optionally in protected form, and any protecting groups present are removed; and, if desired, converting a free compound I obtainable according to the process into a salt or converting a salt of a compound I obtainable according to the process into the free compound I or into another salt. The reactions described above and below in the variants are carried out, for example in the absence or, customarily, in the presence of a suitable solvent or diluent or a mixture thereof, the reaction, as required, being carried out with cooling, at room temperature or with warming, for example in a temperature range from about -80°C up to the boiling point of the reaction medium, preferably from about -10° to about +200°C, and, if necessary, in a closed vessel, under pressure, in an inert gas atmosphere and/or under anhydrous conditions.

Reactive acid derivatives of compounds of formula (lla) are for example derived activated esters or reactive anhydrides, and also reactive cyclic amides. The reactive acid derivatives can be formed in situ.

Activated esters of compounds of formula (lla) having a carboxy group are especially esters unsaturated at the linking carbon atom of the esterifying radical, for example of the vinyl ester type, such as vinyl esters (obtainable, for example, by trans¬ esterification of a corresponding ester with vinyl acetate; activated vinyl ester method), carbamoyl esters (obtainable, for example, by treatment of the corresponding acid with an isoxazolium reagent; 1 ,2-oxazolium or Woodward method), or 1 -lower alkoxyvinyl esters (obtainable, for example, by treatment of the corresponding acid with a lower alkoxy- acetylene; ethoxyacetylene method), or esters of the amidino type, such as N,N'-disub- stituted amidino esters (obtainable, for example, by treatment of the corresponding acid with a suitable N,N '-disubstituted carbodiimide, for example N,N'-dicyclohexylcarbodiimide; carbodiimide method), or N,N-disubstituted amidino esters (obtainable, for example, by treatment of the corresponding acid with an N,N-disubstituted cyanamide; cyanamide method), suitable aryl esters, especially phenyl esters suitably substituted by electron- attracting substituents (obtainable, for example, by treatment of the corresponding acid with a suitably substituted phenol, for example 4-nitrophenol, 4-methylsulfonylphenol, 2,4,5- trichlorophenol, 2,3,4,5,6-pentachlorophenol or 4-phenyldiazophenol, in the presence of a condensation agent, such as N.N'-dicyclohexylcarbodiimide; activated aryl esters method), cyanomethyl esters (obtainable, for example, by treatment of the corresponding acid with chloroacetonitrile in the presence of a base; cyanomethyl esters method), thioesters, especially unsubstituted or substituted, for example nitro-substituted, phenylthio esters (obtainable, for example, by treatment of the corresponding acid with unsubstituted or substituted, for example nitro-substituted, thiophenols, inter alia by the anhydride or carbodiimide method; activated thiol esters method), or especially amino or amido esters (obtainable, for example, by treatment of the corresponding acid with an N-hydroxyamino or N-hydroxyamido compound, for example N-hydroxysuccinimide, N-hydroxypiperidine, N- hydroxyphthalimide, N-hydroxy-5-norbornene-2,3-dicarboxylic acid imide, 1-hydroxybenzo- triazole or 3-hydroxy-3,4-dihydro-1 ,2,3-benzotriazin-4-one, for example by the anhydride or carbodiimide method; activated N-hydroxy esters method). Intemal esters, for example γ- lactones, can also be used.

Anhydrides of acids may be symmetric or preferably mixed anhydrides of those acids, for example anhydrides with inorganic acids, such as acid halides, especially acid fluorides (obtainable, for example by treatment of the corresponding acid with suitable fluorinating agents such as 1 ,1-difluoro-3-trifluoro-propyleneoxide, 2-fluoro-1 ,3-dimethyl- pyridinium benzenesulfonate, dimethyl-difluoromethyl-amine, benzoylfluoride, perfluoro- 2methyl-pentene, hexafluoropropane, thfluorotuoluene/BF₃ and especially cyanuric fluioride), acid chlorides (obtainable, for example, by treatment of the corresponding acid with thionyl chloride, phosphorus pentachloride, phosgene or oxalyl chloride; acid chloride method), azides (obtainable, for example, from a corresponding acid ester via the corresponding hydrazide by treatment thereof with nitrous acid; azide method), anhydrides with carbonic acid semi-esters, for example carbonic acid lower alkyl semi-esters (obtainable, for example, by treatment of the corresponding acid with chloroformic acid lower alkyl esters such as isopropylchlorformate or with a 1 -lower alkoxycarbonyl-2-lower alkoxy-1 ,2-dihydroquinoline; mixed O-alkylcarbonic acid anhydrides method), or anhydrides with dihalogenated, especially dichlorinated, phosphoric acid (obtainable, for example, by treatment of the corresponding acid with phosphorus oxychloride; phosphorus oxychloride method), anhydrides with other phosphoric acid derivatives (for example those obtainable with phenyl-N-phenylphosphoramidochloridate or by reaction of alkylphosphoric acid amides in the presence of sulfonic acid anhydrides and/or racemisation-reducing additives, such as N-hydroxybenzotriazole, or in the presence of cyanophosphonic acid diethyl ester) or with phosphorous acid derivatives, or anhydrides with organic acids, such as mixed anhydrides with organic acids, such as mixed anhydrides with organic carboxylic acids (obtainable, for example, by treatment of the corresponding acid with an unsubstituted or substituted lower alkane- or phenyl-lower alkane-carboxylic acid halide, for example phenylacetic acid chloride, pivalic acid chloride or trifluoroacetic acid chloride; mixed carboxylic acid anhydrides method) or with organic sulfonic acids (obtainable, for example, by treatment of a salt, such as an alkali metal salt, of the corresponding acid with a suitable organic sulfonic acid halide, such as lower alkane- or aryl-, for example methane- or p- toluene-sulfonic acid chloride; mixed sulfonic acid anhydrides method) and symmetric anhydrides (obtainable, for example, by condensation of the corresponding acid in the presence of a carbodiimide or 1-diethylaminopropyne; symmetric anhydrides method).

Suitable cyclic amides are especially amides having five-membered diazacycles of aromatic character, such as amides with imidazoles, for example imidazole (obtainable, for example, by treatment of the corresponding acid with N,N'-carbonyldiimidazole; imidazole method), or pyrazole, for example 3,5-dimethylpyrazole (obtainable, for example, via the acid hydrazide by treatment with acetylacetone; pyrazolide method).

Process Variant a):

The condensation for forming an amide bond can be carried out in a manner known per se, for example, as described in:

"Houben-Weyl, Methoden der organischen Chemie", 4.ed., Vol. 15/11 (1974), Vol. IX (1955), Vol. E11 (1985), Georg Thieme Verlag, Stuttgart;

"The Peptides" (E. Gross and J. Meienhofer, Ed.) Vol. 1 and 2, Academic Press, London and New York, 1979/1980; or "Principles of Peptide Synthesis", M. Bodansky, Springer-Verlag, Berlin, 1984.

For example, the condensation of a free carboxylic acid (lla) with the corresponding amine (lib) can be carried out preferably in the presence of one of the customary condensation agents, or using as a corresponding reactive acid derivative carboxylic acid anhydrides or carboxylic acid halides, such as chlorides, or activated carboxylic acid esters, such as p-nitrophenyl esters. Customary condensation agents are, for example, carbodiimides, for example diethyl-, dipropyl-, 1-(3-dimetylaminopropyl)-3-ethyl-carbodiimide or especially dicyclohexylcarbodiimide, also suitable carbonyl compounds, for example carbonylimidazole, 1 ,2-oxazolium compounds, for example 2-ethyl-5-phenyl-1 ,2-oxazolium 3'-sulfonate and 2-tert-butyl-5-methylisoxazolium perchlorate, or a suitable acylamino compound, for example 2-ethoxy-1-ethoxycarbonyl-1 ,2-dihydroquinoline, N,N,N',N'-- tetraalkyluronium compounds, such as O-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate, also activated phosphoric acid derivatives, for example diphenyl¬ phosphoryl azide, diethylphosphoryl cyanide, phenyl-N-phenylphosphoroamidochloπdate, bιs(2-oxo-3-oxazolιdιnyl)phosphinιc acid chloride or l -benzotrιazolyloxy-trιs(dιmethylamιno)- phosphonium hexafluorophosphate.

If desired, an organic base is added, preferably a tertiary amine, for example a tri- lower alkylamine having bulky radicals, for example ethyl diisopropylamine or triethylamine, and/or a heterocyclic base, for example 4-dιmethylamιnopyrιdιne or preferably N-methyl- morpholine or pyridine.

The condensation of activated esters, reactive anhydrides or reactive cyclic amides with the corresponding amines (lib) is customarily carried out in the presence of an organic base, for example simple tri-lower alkylamines, for example triethylamine or tributylamine, or one of the above-mentioned organic bases. If desired, a condensation agent is additionally used, for example as described for free carboxylic acids.

The condensation of acid anhydrides with amines (lib) can be effected, for example, in the presence of inorganic carbonates, for example ammonium or alkali metal carbonates or hydrogen carbonates, such as sodium or potassium carbonate or hydrogen carbonate (if desired together with a sulfate).

Carboxylic acid chlorides, for example the chlorocarbonic acid derivatives, derived from the acid of formula (lla). The condensation of a free carboxylic acid with the corresponding amine (lib) can be carried out preferably in the presence of one of the customary condensation agents, or using carboxylic acid anhydrides or carboxylic acid halides, such as chlorides, or activated carboxylic acid esters, such as p-nitrophenyl esters. Customary condensation agents are, for example, carbodiimiαes, for example diethyl-, dipropyl-, 1-(3-dimethylamιnopropyl)-3-ethyl-carbodιιmιde or especially dicyclohexylcarbo¬ diimide, also suitable carbonyl compounds, for example carbonylimidazole, 1 ,2-oxazolιum compounds, for example 2-ethyl-5-phenyl-1 ,2-oxazolιum 3'-sulfonate and 2-tert-butyl-5- methylisoxazolium perchlorate, or a suitable acylamino compound, for example 2-ethoxy-1- ethoxycarbonyl-1 ,2-dihydroαuιnolιne, N,N,N',N'-tetraalkyluronιum compounds, such as O- benzotπazol-1-yl-N,N,N',N'-tetramethyluronιum hexafluorophosphate, also activated phosphoric acid derivatives, for example diphenylphosDhoryl azide, diethylphosphoryl cyanide, phenyl-N-phenylphosphoroamidochloridate, bis(2-oxo-3-oxazolidinyl)phosphinic acid chloride or 1 -benzotriazolyloxy-tris(dimethylamino)phosphonium hexafluorophosphate.

If desired, an organic base is added, preferably a tertiary amine, for example a tri- lower alkylamine having bulky radicals, for example ethyl diisopropylamine or triethylamine, and/or a heterocyclic base, for example 4-dimethylaminopyridine or preferably N-methyl- morpholine or pyridine.

The condensation reactions when starting from an essentially pure isomeric carboxylic acid fluoride surprisingly result in essentially pure isomeric condensation products without inversion of the optical center.

The condensation of acid anhydrides with amines can be effected, for example, in the presence of inorganic carbonates, for example ammonium or alkali metal carbonates or hydrogen carbonates, such as sodium or potassium carbonate or hydrogen carbonate (if desired together with a sulfate).

Carboxylic acid chlorides, for example the chlorocarbonic acid derivatives derived from the acid of formula (lla) are condensed with the corresponding amines preferably in the presence of an organic amine (Mb), for example the above-mentioned tri-lower alkylamines or heterocyclic bases, where appropriate in the presence of a hydrogen sulfate.

The condensation is preferably carried out in an inert, aprotic, preferably anhydrous, solvent or solvent mixture, for example in a carboxylic acid amide, for example formamide or dimethylformamide, a halogenated hydrocarbon, for example methylene chloride, carbon tetrachloride or chlorobenzene, a ketone, for example acetone, a cyclic ether, for example tetrahydrofuran, an ester, for example ethyl acetate, or a nitrile, for example acetonitrile, or in a mixture thereof, as appropriate at reduced or elevated temperature, for example in a temperature range of from approximately -40°C to approximately +100°C, preferably from approximately -10°C to approximately +50°C, and in the case where arylsulfonyl esters are used also at approximately from +100°C to +200°C, and where appropriate under an inert gas atmosphere, for example a nitrogen or argon atmosphere.

Aqueous, for example alcoholic, solvents, for example ethanol, or aromatic solvents, for example benzene or toluene, may also be used. When alkali metal hydroxides are present as bases, acetone can also be added where appropriate.

The condensation can also be carried out in accordance with the technique known as solid phase synthesis which originates from R. Merrifield and is described, for example, in Angew. Chem. 97, 801 - 812 (1985), Naturwissenschaften 71, 252 - 258 (1984) or in R. A. Houghten, Proc. Natl. Acad. Sci. USA 82, 5131 - 5135 (1985).

Reactive acid derivatives can also be formed in situ.

Dependend on the acidic or basic nature of the starting material of formula (lib) it may be used in form of an acid addition salt or in form of a salt with a base, for example, as mentioned above. E.g. sulfonamides may be used in form of an alkali metal salt such as a sodium or potassium salt, whereas if an hydoxylamine derivative is used it may be used as hydrohalide such as hydrochloride.

Starting material of formulae (lla) and (lib) is either known or can be manufactured, for example, as outlined in the working examples.

Process Variant b):

Diastereomer mixtures can be separated into the pure isomers in a known manner on the basis of the physicochemical differences of the components, for example by fractional crystallization. Diastereomers may furthermore be resolved into the optical antipodes by known methods, for example by recrystallization from an optically active solvent, chromatography on chiral adsorbents, e.g. using conventional HPLC technics, with the aid of suitable microorganisms, by cleavage with specific immobilized enzymes, via the formation of inclusion compounds, for example using chiral crown ethers, only one enantiomer being complexed, and separation of the diastereomer mixture obtained in this manner, for example on the basis of its differing solubilities, into the diastereomers from which the desired enantiomer can be liberated by the action of suitable agents. The more active enantiomer is advantageously isolated.

Functional groups in starting materials that are not to participate in the reaction, especially carboxy, can be protected by suitable protecting groups (conventional protecting groups) which are customarily used in the synthesis of peptide compounds.

Those protecting groups may already be present in the precursors and are intended to protect the relevant functional groups against undesired secondary reactions, such as acylation, esterification, or solvolysis, etc.. In certain cases the protecting groups can additionally cause the reactions to proceed selectively, for example stereoselectively. It is a characteristic of protecting groups that they can be removed easily, i.e. without undesired secondary reactions, for example by solvolysis, reduction, photolysis, and also enzymat¬ ically, for example also under physiological conditions. Radicals analogous to protecting groups may, however, also be present in the end products. Hereinbefore and hereinafter, it is protecting groups in the narrower sense that are referred to unless the relevant radicals are present in the end products.

The protection of functional groups by such protecting groups, the protecting groups themselves and the reactions for their removal are described, for example, in standard works such as J. F. W. McOmie, "Protective Groups in Organic Chemistry", Plenum Press, London and New York 1973, in Th. W. Greene, "Protective Groups in Organic Synthesis", Wiley, New York 1981 , in "The Peptides"; Volume 3 (E. Gross and J. Meienhofer, eds.), Academic Press, London and New York 1981 , in "Methoden der organischen Chemie", Houben-Weyl, 4th edition, Volume 15/1, Georg Thieme Verlag, Stuttgart 1974, in H.-D. Jakubke and H. Jescheit, "Aminosauren, Peptide, Proteine" ("Amino acids, peptides, proteins"), Verlag Chemie, Weinheim, Deerfield Beach and Basel 1982, and in Jochen Lehmann, "Chemie der Kohlenhydrate: Monosaccharide und Derivate" ("The Chemistry of Carbohydrates: monosaccharides and derivatives"), Georg Thieme Verlag, Stuttgart 1974. A carboxy group is protected, for example, in the form of an ester group which can be removed selectively under mild conditions. A carboxy group protected in esterified form is esterified especially by a lower alkyl group that is preferably branched in the 1 -position of the lower alkyl group or substituted in the 1- or 2-position of the lower alkyl group by suit¬ able substituents.

A protected carboxy group esterified by a lower alkyl group is, for example, methoxy¬ carbonyl or ethoxycarbonyl.

A protected carboxy group esterified by a lower alkyl group that is branched in the 1 - position of the lower alkyl group is, for example, tert-lower alkoxycarbonyl, for example tert- butoxycarbonyl.

A protected carboxy group esterified by a lower alkyl group that is substituted in the 1 - or 2-position of the lower alkyl group by suitable substituents is, for example, aryl- methoxycarbonyl having one or two aryl radicals, wherein aryl is phenyl that is unsubstituted or mono-, di- or tri-substituted, for example, by lower alkyl, for example tert-lower alkyl, such as tert-butyl, lower alkoxy, for example methoxy, hydroxy, halogen, for example chlorine, and/or by nitro, for example benzyloxycarbonyl, benzyloxycarbonyl substituted by the mentioned substituents, for example 4-nitrobenzyloxycarbonyl or 4-methoxybenzyloxy- carbonyl, diphenylmethoxycarbonyl or diphenylmethoxycarbonyl substituted by the mentioned substituents, for example di(4-methoxyphenyl)methoxycarbonyl, and also carboxy esterified by a lower alkyl group, the lower alkyl group being substituted in the 1 - or 2-position by suitable substituents, such as 1 -lower alkoxy-lower alkoxycarbonyl, for example methoxymethoxycarbonyl, 1 -methoxyethoxycarbonyl or 1-ethoxyethoxycarbonyl, 1 -lower alkylthio-lower alkoxycarbonyl, for example 1 -methylthiomethoxycarbonyl or 1-ethyl- thioethoxycarbonyl, aroylmethoxycarbonyl wherein the aroyl group is benzoyl that is unsubstituted or substituted, for example, by halogen, such as bromine, for example phenacyloxycarbonyl, 2-halo-lower alkoxycarbonyl, for example 2,2,2-trichloroethoxy- carbonyl, 2-bromoethoxycarbonyl or 2-iodoethoxycarbonyl, as well as 2-(tri-substituted silyl)- lower alkoxycarbonyl wherein the substituents are each independently of the others an aliphatic, araliphatic, cycloaliphatic or aromatic hydrocarbon radical that is unsubstituted or substituted, for example, by lower alkyl, lower alkoxy, aryl, halogen and/or by nitro, for example lower alkyl, phenyl-lower alkyl, cycloalkyl or phenyl each of which is unsubstituted or substituted as above, for example 2-tri-lower alkylsilyl-lower alkoxycarbonyl, such as 2-tri- lower alkylsilylethoxycarbonyl, for example 2-trimethylsilylethoxycarbonyl or 2-(di-n-butyl- methyl-silyl)-ethoxycarbonyl, or 2-triarylsilylethoxycarbonyl, such as triphenyl- silylethoxycarbonyl.

A carboxy group can also be protected in the form of an organic silyloxycarbonyl group. An organic silyloxycarbonyl group is, for example, a tri-lower alkylsilyloxycarbonyl group, for example tnmethylsilyloxycarbonyl. The silicon atom of the silyloxycarbonylgroup can also be substituted by two lower alkyl groups, for example methyl groups, and the amino group or the carboxy group of a second molecule of formulal. Compounds having such protecting groups can be prepared, for example, using dimethylchlorosilane as silylating agent.

A protected carboxy group is preferably lower alkoxycarbonyl, for example methoxy-, ethoxy- or tert-butoxycarbonyl, benzyloxycarbonyl, 4-nitrobenzyloxycarbonyl, 9- fluorenylmethoxycarbonyl or diphenylmethoxycarbonyl.

The removal of protecting groups that are not constituents of the desired end product of formulal, for example the carboxy-protecting groups, is effected in a manner known per se, for example by means of solvolysis, especially hydrolysis, alcoholysis or acidolysis, or by means of reduction, especially hydrogenolysis or chemical reduction, as well as by photolysis, as appropriate stepwise or simultaneously, it being possible also to use enzymatic methods. The removal of the protecting groups is described, for example, in the standard works mentioned above in the section relating to "Protecting groups".

For example, protected carboxy, for example lower alkoxycarbonyl, tert-lower alkoxycarbonyl, lower alkoxycarbonyl substituted in the 2-position by a trisubstituted silyl group or in the 1 -position by lower alkoxy or lower alkylthio, or unsubstituted or substituted diphenylmethoxycarbonyl can be converted into free carboxy by treatment with a suitable acid, such as formic acid, hydrogen chloride or trifluoroacetic acid, where appropriate with the addition of a nucleophilic compound, such as phenol or anisole. Carboxy can also be freed from lower alkoxycarbonyl by means of bases, such as hydroxides, for example alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide or potassium hydroxide. Unsubstituted or substituted benzyloxycarbonyl can be freed, for example, by means of hydrogenolysis, i.e. by treatment with hydrogen in the presence of a metal hydrogenation catalyst, such as a palladium catalyst. In addition, suitably substituted benzyloxycarbonyl, such as 4-nιtrobenzyloxycarbonyl, can also be converted into free carboxy by reduction, for example by treatment with an alkali metal dithionate, such as sodium dithionate, or with a reducing metal, for example zinc, or a reducing metal salt, such as a chromιum(ll) salt, for example chromιum(ll) chloride, customarily in the presence of a hydrogen-yielding agent that, together with the metal, is capable of producing nascent hydrogen, such as an acid, especially a suitable carboxylic acid, such as an unsubstituted or substituted, for example hydroxy-substituted, lower alkanecarboxylic acid, for example acetic acid, formic acid, glycolic acid, diphenylglycohc acid, lactic acid, mandelic acid, 4-chloromandelιc acid or tartaric acid, or in the presence of an alcohol or thiol, water preferably being added. By treatment with a reducing metal or metal salt, as described above, 2-halo-lower alkoxy¬ carbonyl (where appropriate after conversion of a 2-bromo-lower alkoxycarbonyl group into a corresponding 2-ιodo-lower alkoxycarbonyl group) or aroylmethoxycarbonyl can also be converted into free carboxy. Aroylmethoxycarbonyl can also be cleaved by treatment with a nucleophilic, preferably salt-forming, reagent, such as sodium thiophenolate or sodium iodide 2-(trι-substituted silyl)-lower alkoxycarbonyl, such as 2-trι-lower alkylsilyl-lower alkoxycarbonyl, can also be converted into free carboxy by treatment with a salt of hydrofluoric acid that yields the fluoride anion, such as an alkali metal fluoride, for example sodium or potassium fluoride, where appropriate in the presence of a macrocyclic polyether ("Crown ether"), or with a fluoride of an organic quaternary base, such as tetra-lower alkyl- ammonium fluoride or tri-lower alkylaryl-lower alkylammonium fluoride, for example tetra- ethylammonium fluoride or tetrabutylammonium fluoride, in the presence of an aprotic, polar solvent, such as dimethyl sulfoxide or N.N-dimethylacetamide. Carboxy protected in the form of organic silyloxycarbonyl, such as tri-lower alkylsilyloxycarbonyl, for example tnmethylsilyloxycarbonyl, can be freed in customary manner by solvolysis, for example by treatment with water, an alcohol or an acid, or, furthermore, a fluoride, as described above Esterified carboxy can also be freed enzymatically, for example by means of esterases or suitable peptidases, for example esterified arginine or lysine, such as lysine methyl ester, using trypsin

The invention relates in particular to the processes described in the examples.

Salts of compounds of the formula I can be prepared in a manner known per se. Thus, for example, acid addition salts of compounds of the formula I are obtained by treating with an acid or a suitable ion exchange reagent Salts can be converted into the free compounds in a customary manner, and acid addition salts can be converted, for example, by treating with a suitable basic agent.

Depending on the procedure and reaction conditions, the compounds according to the invention having salt-forming, in particular basic properties, can be obtained in free form or preferably in the form of salts.

In view of the close relationship between the novel compound in the free form and in the form of its salts, in the preceding text and below the free compound or its salts may correspondingly and advantageously also be understood as meaning the corresponding salts or the free compound.

The novel compounds including their salts of salt-forming compounds can also be obtained in the form of their hydrates or can include other solvents used for crystallization.

Depending on the choice of the starting materials and procedures, the novel compounds can be present in the form of one of the possible isomers or as mixtures thereof, for example as pure optical isomers, such as antipodes, or as isomer mixtures, such as racemates, diastereoisomer mixtures or racemate mixtures, depending on the number of asymmetric carbon atoms.

Acid addition salts can be prepared by neutralizing a compound of the formula (I) having a basic group with an acid or an acidic ion exchanger.

Salts with a base can be prepared by neutralizing a compound of the formula (I) having an acidic group with a base compound.

The invention also relates to those embodiments of the process, according to which a compound obtainable as an intermediate in any step of the process is used as a starting material and the missing steps are carried out or a starting material in the form of a derivative or salt and/or its racemates or antipodes is used or, in particular, formed under the reaction conditions. In the process of the present invention, those starting materials are preferably used which lead to the compounds described as particularly useful at the beginning. The invention likewise relates to novel starting materials which have been specifically developed for the preparation of the compounds according to the invention, to their use and to processes for their preparation. The invention especially relates to novel starting materials their manufacture and use, e.g. as starting material.

The invention likewise relates to pharmaceutical preparations which contain the compounds according to the invention or pharmaceutically acceptable salts thereof as active ingredients, and to processes for their preparation.

The pharmaceutical preparations according to the invention which contain the compound according to the invention or pharmaceutically acceptable salts thereof are those for enteral, such as oral, furthermore rectal, and parenteral administration to (a) warm¬ blooded animal(s), the pharmacological active ingredient being present on its own or together with a pharmaceutically acceptable carrier. The daily dose of the active ingredient depends on the age and the individual condition and also on the manner of administration. The novel pharmaceutical preparations contain, for example, from about 10 % to about 80%, preferably from about 20 % to about 60 %, of the active ingredient.

The pharmacologically active compounds of the invention can be used in the manufacture of pharmaceutical compositions that comprise an effective amount of the same on its own or in conjunction or admixture with excipients or carriers that are suitable for enteral or parenteral administration. Preferred are tablets and gelatin capsules that comprise the active constituent together with a) diluents, for example lactose, dextrose, sucrose, mannitol, sorbitol, cellulose and/or glycine, b) glidants, for example silica, talc, stearic acid, the magnesium or calcium salt thereof and/or polyethylene glycol, for tablets also c) binders, for example magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose and/or polyvinylpyrrolidone, if desired d) dispersing or disintegrating agents, for example starches, agar, alginic acid or the sodium salt thereof, or foaming mixtures and/or e) absorbents, colouring agents, flavourings and sweeteners. Injectable preparations are preferably aqueous isotonic solutions or suspensions, and suppositories are advantageously produced from fatty emulsions or suspensions. These compositions may be sterilised and/or contain adjuvants, such as preservatives, stabilizers, wetting agents or emulsifiers, solubilisers, salts for regulating the osmotic pressure and/or buffers. In addition they may also contain other therapeutically valuable substances. These preparations are manufactured according to conventional mixing, granulating or coating methods and contain approximately from 0.1 to 100%, preferably approximately from 1 to 50%, of the active constituent. A unit dose for a mammal weighing approximately from 50 to 70 kg may contain between approximately 0.2 and 2000 mg, preferably between approximately 1 and 200 mg, of active constituent.

The following examples illustrate the invention described above; however, they are not intended to limit its extent in any manner. Temperatures are indicated in degrees Celsius.

Working Examples:

(I) Starting Material/Intermediates:

Example 1 :

N-Butanesulfonyl-N-trimethylsilylamide

Ammonia gas is bubbled into a solution of 1 -butanesulfonyl chloride (2 g, 12.8 mmol) in acetonitrile (20 ml) at room temperature for 30 minutes. The mixture is filtered and the filtrate is concentrated in vacuo. The residue is diluted with water (20 ml) and extracted with ethyl acetate. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give 1 -butanesulfonylamide as colorless oil.

A solution of 1 -butanesulfonylamide obtained above, triethyl amine (1.84 ml, 13.2 mmol), and chlorotrimethylsilane (1.60 ml, 12.6 mmol) in toluene (30 ml) is refluxed under nitrogen atmosphere for 4 hours. The mixture is filtered and the filtrate is concentrated in vacuo to give N-butanesulfonyl-N-trimethylsilylamide as brown oil.

Example 2:

N-Butanesulfonyl-valineamide hydrochloride

To a cooled (-15°C) solution of t-butoxycarbonylvaline (1.0 g, 4,6 mmol) and pyridine

(0.39 ml) in methylene chloride (11 ml) is dropped cyanuric fluoride (1.87 ml, 13.8 mmol) and the mixture is stirred at -15°C for 1 hour. The reaction mixture is diluted with methylene chloride and ice, and filtered on Celite. The filtrate is diluted with ice water and extracted with methylene chloride. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give t-butoxycarbonylvaline fluoride.

A solution of N-butanesulfonyl-N-trimethylsilylamide (1.72 g, 8.28 mmol), t-butoxycarbonyl¬ valine fluoride (1.01 g, 4.6 mmol), and dimethylaminopyridine (220 mg, 1.84 mol) in tetrahydrofuran (25 ml) is stirred at room temperature for 1 hour. The mixture is diluted with 10 % citric acid and extracted with ethyl acetate. The organic layer is washed with water and brine, dried over magnesium sulfate, and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/hexane (3:1) to give N-butanesulfonyl-(t- butoxycarbonyl)-valineamide.

To a solution of N-butanesulfonyl-(t-butoxycarbonyl)-valineamide (0.70 g, 2.08 mmol) in 1 ,4- dioxane (25 ml) is added 4N HCI/1 ,4-dioxane (30 ml) at room temperature under nitrogen atmosphere and the mixture is stirred for 8 hours. The reaction mixture is concentrated in vacuo and the solid residue is washed with diethyl diethyl ether and dried to give N- butanesulfonyl-valineamide hydrochloride.

Example 3:

N-(3.5-Dimethylbenzoyl)-N-methyl-3-f4-(5-isoxazolyl)-phenylj-(D)-alanine 4-Methylacetophenone (100 g, 0.75 mol) and N.N'dimethylformamide diethylacetal (200 ml, 1.17 mol) are heated on reflux under nitrogen atmosphere for 20 hours. The reaction mixture is cooled at 0°C and crystals precipitated are collected by filtration, washed with cold hexane, and dried to give 3-dimethylamino-1-p-tolylprop-2-en-1-one following the reported procedure [J. Org. Chem., 45, 4857-60 (1980)].

At 0°C a solution of hydroxylamine-O-sulfonic acid (93 g, 0.82 mol) in dry methanol (700°ml) is added over 2 minutes to a solution of 3-dimethylamino-1-p-tolylprop-2-en-1-one (148 g, 0.78 mol) in dry methanol (1 I). The mixture is stirred at ambient temperature for 20 minutes, then carefully poured into a solution of sodium bicarbonate (150 g, 1.79 mol) in water (11 I). After standing at room temperature over night, the precipitates are collected and dried to give crude 5-(4-methylphenyl)-isoxazole. In order to obtain purer product, the material can be purified by flash chromatography on silica gel, using hexane/ethyl acetate (4:1) as eluent. To a solution of 5-(4-methylphenyl)-isoxazole (17 g, 0.11 mol) and N-bromosuccinimide (19 g) in tetrachloromethane (500 ml) under nitrogen, bis benzoyl peroxide (0.43 g, 1.78 mol) is added, and the mixture is heated on reflux over night. The solvent is evaporated, and the residue is purified by flash chromatography (silica gel, hexane/ethyl acetate 4:1) to give pure 5-(4-bromomethylphenyl)-isoxazole.

5-(4-Bromomethylphenyl)-isoxazole (26 g, 1.78 mol) and N-(diphenylmethylene)-glycine ethyl ester (32.5 g, 0.12 mol) is dissolved in dichloromethane (750 ml) and stirred vigorously with a solution of tetrabutylammonium hydrogensulfate (40.7 g, 0.12 mol) in 2.5 N sodium hydroxide solution (940 ml) at room temperature over night. The organic layer is then separated off and concentrated. The residue is partitioned between ether and water, the ether phase is washed with water and brine, dried over magnesium sulfate and evaporated to give crude N-diphenylmethylene-3-[4-5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester.

Crude N-diphenylmethylene-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester (280 mg, 0.66 mmol) is treated with p-toluenesulfonic acid monohydrate (100 mg, 0.56 mmol) in acetonitrile (35 ml) and water (3.5 ml) at ambient temperature for 3.5 hours. After concentration, the residue is extracted with ether and 1 sodium hydroxide, washed with brine, dried, and concentrated. The crude mixture is chromatographed on silica with hexane/ethyl acetate (1 :9) to give 3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester.

To a solution of 3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester (1 g, 3.84 mmol) in ethanol (2 ml) is added (2 ?,3fi)-(-)-O,O'-dibenzoyltartaric acid monohydrate (361 mg, 0.96 mmol) and dissolved at 60°C, then the mixture is cooled to room temperature. After 1 day, colorless needles are collected and washed with cold ethanol (1 ml). The crystals are dissolved in half saturated sodium bicarbonate (10 ml) and extracted with ethyl acetate (2 x 10 ml). The combined organic layer is washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give 3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine ethyl ester.

To a solution of 3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine ethyl ester (1.36 g, 4,6 mmol) in ether (5 ml) is added 4N hydrochloric acid in 1 ,4-dioxane solution (1.5 ml). Stirring is continued for 30 minutes. The reaction mixture is diluted with ether and cooled to 0°C. White precipitates are collected and dried. To a suspension of the precipitates (1.23 g, 4.14 mmol), tetrahydrofuran (1.23 ml), and water (1.23 mi) is added formalin (0.61 ml) and distilled cyclopentadiene (1.03 ml, 12 mmol). Stirring is continued at room temperature for 2.5 hours. The reaction mixture is diluted with water (10 ml) and washed with hexane (3 x 10 ml). The aqueous layer is made basic with 4 % sodium bicarbonate solution (10 ml) and extracted with ethyl acetate (3 x 10 ml). The organic layer is dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue is dissolved in chloroform (20 ml) and to the solution are added trifluoroacetic acid (20 ml) and triethylsilane (2 ml) under nitrogen atmosphere at room temperature. The mixture is stirred for 20 hours and concentrated in vacuo. The residue is made basic with 4 % sodium bicarbonate (10 ml) and extracted with ethyl acetate (3 x 10 ml). The organic layer is washed with brine and dried over magnesium sulfate, filtered and concentrated in vacuo to give N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)- alanine ethyl ester as a yellow oil.

To a mixture of N-methyl-3-[4-(5- isoxazolyi)-phenyl]-(D)-alanine ethyl ester (1.62 g, 5.0 mmol), chloroform (10 ml), and 2N sodium carbonate solution (2.1 ml) is added 3,5- dimethylbenzoyl chloride (1.39 g, 12 mmol) under nitrogen atmosphere at 0°C. Stirring is continued at 0°C for 1 hour and at room temperature for 2 hours. The reaction mixture is diluted with water and extracted with methylene chloride. The organic layer is washed with 10 % citric acid solution and brine, and dried over magnesium sulfate, filtered and concentrated in vacuo. The crude material is chromatographed on silica with hexane/ethyl acetate (4:1) to give N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)- alanine ethyl ester.

To a mixture of N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine ethyl ester (720 mg, 1.78 mmol) and methanol (12 ml), water (6 ml), and tetrahydrofuran (6 ml) is added lithium hydroxide mono hydrate (78.7 mg, 1.87 mmol) at 0°C under nitrogen atmosphere. Stirring is continued at 0°C for 1 hour and at room temperature for 2 hours. The reaction mixture is diluted with water and washed with ether. The aqueous layer is acidified with 1 N hydrochloric acid and extracted with ethyl acetate. The organic layer is washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine. [α]_D + 15.5° (c=1.0, ethanol). Example 4:

N-(3,5-Dimethylbenzoyl)-N-methyl-3-f4-(5-isoxazolyl)-phenyl|-(D)-alanine

To a solution of crude 3-[4-(5- isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester (2.24 g,

8.61 mmol) in N,N'-dimethylformamide (15 ml) are added 3,5-dimethylbenzoic acid (1.42 g,

9.47 mmol) and 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (1.82 g,

0.86 mmol) at 0°C. The mixture is stirred at 0°C for 1 hour and at room temperature overnight. The mixture is diluted with water and extracted with ethyl acetate. The organic layer is dried over magnesium sulfate, and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/hexane (1 :1) to give N-(3,5-dimethyl- benzoyl)-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester.

A solution of N-(3,5-dimethylbenzoyl)-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester (3.8 g, 9.7 mmol) and iodomethane (1.8 ml, 28.9 mmol) in dry N, N-dimethylformamide (40 ml) is cooled in an ice bath and sodium hydride (60 % in oil, 390 mg, 9.8 mmol) is added in portions. The mixture is allowed to warm to room temperature during 5 hours, then poured into water, extracted with ethyl acetate. The organic phase is washed with water, and with brine, dried and evaporated. Flash chromatography of the residue on silica gel (hexane/ethyl acetate 3:1) gives N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)- phenyl]-(D,L)-alanine ethyl ester.

N-(3,5-Dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine ethyl ester (44 mg, 0.11 mmol) is treated with lithium hydroxide monohydrate (5 mg, 0.12 mmol) in methanol (0.5 ml), tetrahydrofurane (0.25ml), and water (0.25 ml) for 3 hours at room temperature. The mixture is then extracted with ether and water, the aqueous phase is acidified with 1 N hydrochloric acid, and subsequently extracted with ethyl acetate. The organic phase is washed with brine, dried over magnesium sulfate, and evaporated in vacuo to give N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine.

To a solution of N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine (1.71 g, 4.52 mmol) and (R)-(-)-2,2-dimethyl-1 ,3-dioxolane-4-methanol (0.78 g, 5.88 mmol) in methylene chloride (80 ml) are added 1 ,3-diisopropylcarbodiinπide (1.06 ml, 6.78 mmol) and then dimethylaminopyridine (1 10 mg, 0.904 mmol) under nitrogen atmosphere at 0°C. The mixture is allowed to warm up to room temperature overnight, diluted with water, and extracted with ethyl acetate. The organic layer is dried over magnesium sulfate and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/hexane (1 :1) to give N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]- (D.L)-alanine [(R)-(-)-2,2-dimethyl-1 ,3-dioxolane-4-yl]-methyl ester. The diastereomeric mixture) is separated by HPLC [Shim-pack PREP-SIL (L), hexane/isopropanol (95:5)] into a less polar isomer N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine [(R)-(-)-2,2-dimethyl-1 ,3-dioxolane-4-yl]-methyl ester (16) and a more polar isomer N-(3,5- dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(L)-alanine [(R)-(-)-2,2-dimethyl-1 ,3- dioxolane-4-yl]-methyl ester.

A mixture of N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine [(R)-(- )-2,2-dimethyl-1 ,3-dioxolane-4-yl]-methyl ester (151.5 mg, 0.308 mmol), lithium hydroxide monohydrate (13.5 mg, 0.323 mmol), methanol (5 ml), tetrahydrofuran (2.5 ml), and water (2.5 ml) is stirred at 0°C for 1 hour and at room temperature for 3 hours. The reaction mixture is condensed in vacuo and the residue is diluted with water and washed with ethyl acetate three times. The aqueous layer is acidified with 1 N HCl and extracted with ethyl acetate. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanine.

Example 5:

N-(3.5-Dimethylbenzoyl)-N-methyl-3-r4-n .2.4-triazol-1-yl)-phenvn-(D.Lι-alanine A mixture of 3,5-dimethylbenzamide (22.6g, 0.15mol) and glyoxylic acid monohydrate (15.3g, 0.17mol) in acetone (120ml) is heated under nitrogen atmosphere at reflux for 6h. The solvent is evaporated in vacuo to give 2-hydroxy-N-(3,5-dimethylbenzoyl)glycine. To a solution of 2-hydroxy-N-(3,5-dimethylbenzoyl)glycine in methanol (350ml) is added concentrated sulfuric acid (4.6ml) at room temperature. The mixture is stirred for 2days and then concentrated in vacuo. The residue is diluted with ethyl acetate, washed with two portions of saturated sodium bicarbonate solution and with two portions of brine. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give 2-methoxy- N-(3,5-dimethylbenzoyl)glycine methyl ester.

To a solution of 2-methoxy-N-(3,5-dimethylbenzoyl)glycine methyl ester (16.7g, 66.5mmol) in toluene (70ml) under nitrogen atmosphere is added phosphorus thrichloride (6.0ml, 68.7mmol) at room temperature. The reaction mixture is heated at 70°C for 16h. Then, trimethyl phosphite (8.1 ml, 68.7mmol) is added dropwise to the stirred mixture at 70°C and stirring is continued for further 2h at 70°C. The solvent is evaporated in vacuo. The residue is diluted with hexane, filtered, and washed with ethyl acetate. The combined filtrate is concentrated in vacuo and the crude material is purified by column chromatography on silica with ethyl acetate to give trimethyl 2-(3,5-dimethylbenzoyl)amino-phosphonoacetate.

A mixture of 1 ,2,4-triazole (4.06g, 58.7mmol), potassium carbonate (9.05g, 65.5mmol), 4- fluorobenzaldehyde (6.3ml, 58.7mmol), and copper(l) oxide (0.26g, 1.82mmol) in pyridine (30ml) is heated under nitrogen atmosphere at reflux overnight. After pyridine is distilled, the residue is diluted with chloroform, filtered, and washed with chloroform. The combined filtrate is washed with water, dried over magnesium sulfate, and concentrated in vacuo. The crude material is purified by column chromatography on silica with hexane/ethyl acetate (1 :2) to give 4-(1 ,2,4-triazol-1-yl)-benzaldehyde and with ethyl acetate/methanol (19:1) to give 4-(1 ,3,4-triazol-1-yl)-benzaldehyde.

To a solution of trimethyl 2-(3,5-dimethylbenzoyl)amino-phosphonoacetate (0.51 g, 1.54mmol) in methylene chloride (3.0ml) under nitrogen atmosphere is added 1 ,8- diazabicyclo[5,4,0]undec-7-ene (0.24ml, 1.60mmol). After 10min, 4-(1 ,2,4-triazol-1-yl)-- benzaldehyde (0.27g, 1.57mmol) is added and stirring is continued for 3h. The reaction mixture is diluted with diethyl ether. The prepicipates are filtered, washed with diethyl ether and water successively, and dried in vacuo to give methyl 2-(3,5-dimethylbenzoyl)amino-3- [4-(1 ,2,4-triazol-1 -yl)phenyl]acrylate.

To a cooled (0°C) solution of methyl 2-(3,5-dimethylbenzoyl)amino-3-[4-(1 ,2,4-triazol-1-yl)- phenyl]-acrylate (0.35g, 0.94mmol) and iodomethane (0.20ml, 3.21 mmol) in N,N'- dimethylformamide (3.0ml) under nitrogen atmosphere is added sodium hydride (0.045g, 60% in oil, 1.12mmol). After 1 h, the mixture is warmed to room temperature and stirred for 1 h. The mixture is diluted with diethyl ether and washed with water and with brine. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give methyl 2- [N-(3,5-dimethylbenzoyl)-N-methyi]amino-3-[4-(1 ,2,4-triazol-1-yl)phenyl]acrylate. A solution of 2-[N-(3,5-dimethylbenzoyl)-N-methyl]amino-3-[4-(1 ,2,4-triazol-l -yl)- phenyl]acrylate (1.50g, 4.5mmol) in methanol (50ml) is hydrogenated over platinum oxide (1 mg) under 3atm hydrogen atmosphere overnight. Catalyst is removed by fitlration and the filtrate is concentrated in vacuo. The crude material is purified by column chromatography on silica with hexane/ethyl acetate (1 :5) to give N-(3,5-dimethylbenzoyl)-N-methyl-3-[4- (1 ,2,4-triazol-1-yl)-phenyl]-(D,L)-alanine methyl ester.

N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1 -yl)-phenyl]-(D,L)-alanine methyl ester (1 ,24g, 3.15mmol) is treated with lithium hydroxide (0.16g, 3.77mmol) in methanolΛetra- hydrofuran/water (1 :1 :1) (30ml) at 0°C. After 2h, the mixture is slowly warmed to room temperature and stirred overnight. The reaction mixture is acidified with 1 N hydrochloric acid (3.8ml), diluted with water, and extracted with chloroform. The organic layer is dried over sodium sulfate and concentrated in vacuo to give N-(3,5-dimethylbenzoyl)-N-methyl-3- [4-(1 ,2,4-triazoM -yl)-phenyl]-(D,L)-alanine.

Example 6:

N-Butanesulfonyl-(L)-theronineaminde

To a cooled (-15°C) solution of t-butoxycarbonyl-O-t-butyl-(L)-threonine (2.09 g, 7.6 mmol) and pyridine (0.62 ml) in methylene chloride (20 ml) is dropped cyanuric fluoride (2.05 ml,

22.8 mmol) and the mixture is stirred at -15°C for 1.5 hours. The reaction mixture is diluted with methylene chloride and crashed ice, and filtered on Celite. The filtrate is diluted with ice water and extracted with methylene chloride. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give t-butoxy-O-t-butyl-(L)-threonine fluoride.

A solution of N-butanesulfonyl-N-trimethylsilylamide (1.86 g, 8.90 mmol), t-butoxycarbonyl- O-t-butyl-(L)-threonine fluoride (1.90 g, 6.85 mmol), and dimethylaminopyridine (333 mg, 2.74 mmol) in tetrahydrofuran (35 ml) is stirred at room temperature overnight. The mixture is diluted with water and extracted with ethyl acetate. The organic layer washed with brine, dried over magnesium sulfate, and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/hexane/acetic acid (9:2:0.1 ) to give N- butaπesulfonyl-(t-butoxycarbonyl-O-t-butyl)-(L)-threonineamide. N-Butanesulfonyl-(t-butoxycarbonyl-O-t-butyl)-(L)-threonineamide (759 mg, 2.29 mmol) is treated with trifluoroacetic acid (5 ml) at 0°C under nitrogen atmosphere and the stirring is continued for 2.5 hours. The reaction mixture is concentrated in vacuo and 4N HCl in 1 ,4- dioxane (4 ml) and diethyl ether is added to the residue. The white precipitates are filtered and washed with diethyl ether. The solid is recrystallized from ethanol to give N- butanesulfonyl-(L)-theronineamide hydrochloride.

Example 7:

N-(3-Hydroxy-5-methyl-benzoyl)-N-methyl-3-f4-(1.2,4-triazol-1-vO-phenyll-(D,L)-alanine To a cooled (0°C) solution of methyl 3-hydroxy-5-methyl-benzoate (Turner.F.A:; Gearien.J.E. J.Org.Chem. 1959, 24, 1952) (1.01 g, 6.10 mmol) and benzyl bromide (0.83 ml, 6.98 mmol) under nitrogen atmosphere is added sodium hydride (60% in oil, 0.31 g, 7.68 mmol). After 1 hour, the mixture is warmed to room temperature and stirred for 2 hours. The mixture is diluted with diethyl ether and washed with water and with brine. The organic layer is dried over magnesium sulfate and concentrated in vacuo to give methyl 3- benzyloxy-5-methyl-benzoate.

Methyl 3-benzyloxy-5-methyl-benzoate (1.77 g, 6.90 mmol) is treated with lithium hydroxide (0.323 g, 7.70 mmol) in methanolΛetrahydrofuran/water (2:1 :1) at 50°C. After 2.5 hours, the mixture is cooled to room temperature, acidified with 1 N hydrochloric acid, diluted with water, and extracted with ethyl acetate The organic layer is washed with brine, dried over magnesium sulfate and concentrated in vacuo to give 3-benzyloxy-5-methyl-benzoic acid.

To a solution of trimethyl 2-benzyloxycarbonylamino-phosphonoacetate (Schmidt.U.; Lieberknecht.A.; Wild.J. Synthesis, 1984, 53) (4.54 g, 13.7 mmol) in methylene chloride (30 ml) under nitrogen atmosphere is added 1 ,8-diazabicyclo[5.4.0]undec-7-ene (2.30 ml, 14.8 mmol). After 10 minutes, 4-(1 ,2,4-triazol-1-yl)-benzaldehyde (2.41 g, 13.9 mmol) is added and stirring is continued overnight. The reaction mixture is diluted with water and extracted twice with diethyl ether. The organic layer is washed with water and with brine, dried over magnesium sulfate, and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/hexane /(2:1) to give methyl 2-benzyloxycarbonylamino-3-[4- (1 ,2,4-triazol-1 -yl)-phenyl]acrylate. To a cooled (0°C) solution of methyl 2-benzyloxycarbonylamino-3-[4-(1 ,2,4-triazol-1 -yl)- phenyljacrylate (3.36 g, 8.88 mmol) and iodomethane (1.66 ml, 26.66 mmol) in N,N'- dimethylformamide (40 ml) under nitrogen atmosphere is added sodium hydride (60% in oil, 0.362 g, 9.05 mmol). After 1 hour, the mixture is quenched with water at 0°C and extracted with diethyl ether. The organic layer is washed with brine, dried over magnesium sulfate and concentrated in vacuo. The crude residue is recrystallized from ethyl acetate and diethyl ether (1 :1) to give methyl 2-[N-benzyloxycarbonyl-N-methyl]amino-3-[4-(1 ,2,4-triazol- 1 -yl)-phenyl]acrylate.

To a solution of methyl 2-[N-benzyloxycarbonyl-N-methyl]amino-3-[4-(1 ,2,4-triazol-1-yl)- phenyl]acrylate (2.67 g, 6.8 mmol) in tetrahydrofuran (30 ml) is hydrogenated over Pd-C (10%, 0.20 g) under 3 atm hydrogen atmosphere overnight. Catalyst is removed by filtration and the filtrate is concentrated in vacuo to give N-methyl-3-[4-(1 ,2,4-triazol-1-yl)- phenyl]-(D,L)-alanine methylester.

To a stirred solution of N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]-(D,L)-alanine methylester (292 mg, 1.12 mmol) in N.N'-dimethylformamide (5.5 ml) under nitrogen atmosphere are added 3-benzoyloxy-5-methylbenzoic acid (333 mg, 1.37 mmol) and 1 -hydroxy- benzotriazole (300 mg, 2.22 mmol). The mixture is cooied to 0°C and 1 -(3- dimethylaminopropyl)-3-carbodiimide (0.30 ml, 1.64 mmol) is added dropwise. After 2 hours, the reaction mixture is slowly warmed to room temperature and stirring is continued overnight. The mixture is diluted with ethyl acetate and washed with water and with brine. The organic layer is dried over magnesium sulfate and concentrated in vacuo. The crude material is purified by column chromatography on silica gel with hexane/ethyl acetate (1 :3) to give N-(3-benzyloxy-5-methyl-benzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1 -yl)-phenyl]-(D,L)- alanine methyl ester.

To a solution of N-(3-benzyloxy-5-methyl-benzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]- (D.L)-alanine methyl ester (0.518 g, 1.07 mmol) in methanol (7.0 ml) are added Pd-C (10%, 0.22 g) and ammonium formate (0.35 g, 5.5 mmol). After being stirred at room temperature for 2 hours, the catalyst is removed by filtration and the filtrate is concentrated in vacuo. The residue is diluted with water and extracted with ethyl acetate. The organic layer is dried over mgnesium sulfate and concentrated in vacuo to give N-(3-hydroxy-5-methyl-benzoyl)- N-methyl-3-[4-(1 ,2,4-triazol-1 -yl)-phenyl]-(D,L)-alanine methyl ester. N-(3-Hydroxy-5-methyl-benzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]-(D,L)-alanine methyl ester (0.397g, 1.01 mmol) is treated with lithium hydroxide (0.118 g, 2.81 mmol) in methanol/tetrahydrofuran/water (2.5:2.5:1) (6 ml) at room temperature. After being stirred for 4 hours, the mixture is concentrated in vacuo. The residue is diluted with water and washed with 2 portions of diethyl ether. The aqueous layer is acidified with 1 N hydrochloric acid (2.85 ml), diluted with brine, and extracted twice with ethyl acetate. The organic layer is dried over sodium sulfate and concentrated in vacuo to give N-(3-hydroxy-5-methyl- benzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]-(D,L)-alanine.

(II) Final Products: Example 1 :

N-Butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanyl1- (L)-valineamide

To a cooled (0°C) solution of 1 -hydroxybenzotriazole (2.57 g, 19.02 mmol), N-butane- sulfonyl-(L)-valineamide hydrochloride (2.94 g, 10,76 mmol) and N-(3,5-dimethylbenzoyl)-N- methyl-3-[4-(5-isoxazolyl)-phenyl]-(D,L)-alanine (4.10 g, 10.82 mmol) in N,N'- dimethylformamide (100 ml) unter nitrogen atmosphere is added dropwise 1-(3- dimethylaminopropyl)-3-ethyl-carbodiimide (1.97 ml, 10.75 mmol). After 2 hours, the reaction mixture is slowly warmed to room temperature and stirring is continued overnight. The reaction mixture is diluted with water and extracted twice with diethyl ether. The organic layer is washed with water and with brine, dried over sodium sulfate, and concentrated in vacuo. The crude residue is recrystallized twice from 2-propanol to give N- butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanyl]-(L)- valineamide; mp.: 194-196°C; [α]_D = + 104.5° (c= 1.00, chloroform).

The residue is purified by preparative HPLC (Ultra silica) with hexane/2-propanol/- trifluoroacetic acid (90:10:0.5) to give N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl- 3-[4-(5-isoxazolyl)-phenyl]-(L)-alanyl]-(L)-valineamide.

Example 2:

N-Butanesulfonyl-fN-(3.5-dimethylbenzoyl)-N-methyl-3-f4-(5-isoxazolvπ-phenvn-(D)-alanyll- (L)-valineamide sodium salt

To a cooled (0°C) solution of N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5- isoxazolyl)-phenyl]-(D)-alanyl]-(L)-valineamide (135 mg, 0.23 mmol) in methanol (2ml) and water (5 ml) is added dropwise 1 N NaOH (0.2 ml, 0.2mmol). After being stirred at 0°C for 30 minutes, the mixture is washed with diethyl ether. Freeze dry of the aqueous layer affrods N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)- alanyl]-(L)-valineamide sodium salt; mp. 112-115°C; [α]_D = +31.3° (c=1.00, methanol).

Example 3: N-Butanesulfonyl-fN-(3.5-dimethylbenzoyl)-N-methyl-3-f4-(1.2,4-triazol-1-yl)-phenvn-(D.L)- alanylHD-valineamide

To a stirred solution of N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]- (D.L)-alanine (213 mg, 0.56 mmol) in N.N'-dimethylformamide (7.0 ml) under nitrogen atmosphere are added N-butanesulfonyl-(L)-valineamide hydrochloride (159 mg, 0.58 mmol) and 1 -hydroxybenzotriazole (150 mg, 1.11 mmol). The mixture is cooled to 0°C and 1 -(3-dimethylaminopropyl)-3-carbodiimide (0.12 ml, 0.65 mmol) is added dropwise. After 2 hours, the reaction mixture is slowly warmed to room temperature and stirring is continued overnight. The reaction mixture is diluted with water and extracted twice with ether. The organic layer is washed with water and with brine, dried over magnesium sulfate and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/methanol (30:1) to give N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4- (1 ,2,4-triazol-1 -yl)-phenyl]-(D,L)-alanyl]-(L)-valineamide.

Example 4:

N-Butanesulfonyl-fN-(3.5-dimethylbenzoyl)-N-methyl-3-r4-(1.2.4-triazol-1-ylj-phenyll-(D.Lι- alanyη-(L)-valineamide hydrochloride

To a stirred solution of N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4- triazol-1-yl)-phenyl]-(D,L)-alanyl]-(L)-valineamide (0.2 g, 0.3 mmol) in ethanol (3 ml) is added a solution of 4N HCl in (1 ,4-dioxane 83 ml, 12 mmol). After 10 minutes, the mixture is concentrated in vacuo. The residue is washed with 2 portions of diethyl ether and dried in vacuo to give N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)- phenyl]-(D,L)-alanyl]-(L)-valineamide hydrochloride.

Example 5:

N-Butanesulfonyl-rN-(3.5-dimethylbenzoyl,-N-methyl-3-f4-(1.2,4-triazol-1 -vn-phenyll-(Dι- alanyl]-(L)-valineamide hydrochloride

A mixture of diastereomers, N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4- triazol-1-yl)-phenyl]-(D,L)-alanyl]-(L)-valineamide, is separated by preparative HPLC (Ultron silica) with hexane/ethanol/trifluoroacetic acid (90:10.0.5) to give N-butanesulfonyl- [N-(3,5- dιmethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-trιazol-1-yl)-phenyl]-(D)-alanyl]-(L)-valιneamιde trifluoroacetic acid salt

and N-butanesulfonyl-[N-(3,5-dιmethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-tπazol-1 -yl)-phenyl]-(L)- alanyl]-(L)-valineamide trifluoroacetic acid salt, respectively. A solution of N-butanesulfonyl- [N-(3,5-dιmethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-trιazol-1-yl)-phenyl]-(D)-alanyl]-(L)-valιne- amide trifluoroacetic acid salt in ethanol is treated with a solution of 4N HCl in 1 ,4-dιoxane and evaporeted in vacuo. The residue is washed with 2 portions of diethyl ether and dried in vacuo to give N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-trιazol-1-yl)- phenyl]-(D)-alanyl]-(L)-valineamide hydrochloride; [α] + 53.71 ° (c=0.7, methanol).

Example 6:

N-Butanesulfonyl-fN-(3.5-dimethylbenzoyl)-N-methyl-3-f4-(1.2.4-triazol-1-ylj-phenyl-(D.L)- alanvn-(L)-threonιneamide

To a stirred solution of N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-tπazol-1-yl)-phenyl]- (D.L)-alanine (350 mg, 0.92 mmol) in N,N'-dimethylformamιde (5.0 ml) under nitrogen atmosphere are added N-butanesulfonyl-(L)-threonιneamιde hydrochloride (280 mg, 1.02 mmol) and 1 -hydroxybenzotriazole (250 mg, 1.85 mmol). The mixture is cooled to 0°C and 1-(3-dιmethylaminopropyl)-3-carbodiιmide (0.190 ml, 1.03 mmol) is added dropwise. After 1 hour, the reaction mixture is slowly warmed to room temperature and stirring is continued overnight The reaction mixture is diluted with 10% citric acid and extracted with chloroform. The organic layer is washed with water and with brine, dried over magnesium sulfate, and concentrated in vacuo. The crude material is purified by preparative thin layer chromato¬ graphy with chloroform/methanol/acetic acid (100:10:1) to give N-butanesulfonyl-[N-(3,5- dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl-(D,L)-alanyl]-(L)-threonineamide.

Example 7:

N-Butanesulfonyl-[N-(3-hvdroxy-5-methylbenzoyl)-N-methyl-3-f4-(1.2,4-triazol-1 -yl)-phenyn- (D.L)-alanyl -(L)-valineamide

To a stirred solution of N-butanesulfonyl-[N-(3-hydroxy-5-methylbenzoyl)-N-methyl-3-[4- (1 ,2,4-triazol-1 -yl)-phenyl]-(D,L)-alanine (272 mg, 0.72 mmol) in N.N'-dimethylformamide (10 ml) under nitrogen atmosphere are added N-butanesulfonyl-(L)-valineamide hydrochloride (253 mg, 0.93 mmol) and 1 -hydroxybenzotriazole (208 mg, 1.54 mmol). The mixture is cooled to 0°C and 1-(3-dimethylaminopropyl)-3-carbodiimide (0.160 ml, 0.87 mmol) is added dropwise. After 2 hours, the reaction mixture is slowly warmed to room temperature and stirring is continued overnight. The reaction mixture is diluted with water and extracted twice with diethyl ether. The organic layer is washed with water and with brine, dried over magnesium sulfate, and concentrated in vacuo. The crude material is chromatographed on silica gel with ethyl acetate/methanol (30:1) to give N-butanesulfonyl-[N-(3-hydroxy-5- methylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]-(D,L)-alanyl]-(L)-valineamide. Example 8:

N-Butanesulfonyl-rN-(3-hvdroxy-5-methylbenzoyl)-N-methyl-3-f4-(1.2.4-triazol-1-yl)-phenyn- (D,L)-alanyl]-(L)-valineamide hydrochloride

To a stirred solution of N-butanesulfonyl-[N-(3-hydroxy-5-methylbenzoyl)-N-methyl-3-[4- (1 ,2,4-triazol-1-yl)-phenyl]-(D,L)-alanyl]-(L)-valineamide (0.2 g, 0.3 mmol) in ethanol (3 ml) is added a solution of 4N HCl in 1 ,4-dioxane (3 ml, 12 mmol). After 10 minutes, the mixture is dried in vacuo. The residue is washed with 2 portions of diethyl ether and dried in vacuo to give N-butanesulfonyl-[N-(3-hydroxy-5-methylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1 -yl)- phenyl]-(D,L)-alanyl]-(L)-valineamide hydrochloride.

Example 9:

In a manner, e.g. as described in any one of the suitable preceeding examples,

N-butanesulfonyl-fN-(3.5-dimethylbenzovπ-N-methyl-3-f4-(1.2.4-triazol-1-vn-phenyl-(D)- alanylj-(LHhreonineamide and

N-butanesulfonyl-fN- (3-hvdroxy-5-methylbenzoyl)-N-methyl-3-l4-(1.2.4-triazol-1 -vD-phenyll-

(D)-alanylHL)-valineamide can be manufactured.

Example 10:

Composition (for 10,000 tablets)

Active ingredient 500.0 g

Lactose 500.0 g

Potato starch 352.0 g

Gelatin 8.0 g

Talc 60.0 g

Magnesium stearate 10.0 g

Silica (highly disperse) 20.0 g

Ethanol q.s.

The active ingredient (e.g. N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5- isoxazolyl)-phenyl]-(D)-alanyl]-(L)-valineamide) is mixed with the lactose and 292 g of potato starch, and the mixture is moistened using an alcoholic solution of the gelatin and granulated by means of a sieve. After drying, the remainder of the potato starch, the talc, the magnesium stearate and the highly disperse silica are admixed and the mixture is compressed to give tablets of weight 145.0 mg each and active ingredient content 50.0 mg which, if desired, can be provided with breaking notches for finer adjustment of the dose.

Example 11 :

Coated tablets, each containing 100 mg of active ingredient, for example, N-butanesulfonyl-

[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanyl]-(L)-valineamide, can be prepared as follows:

Composition (for 1000 tablets):

Active ingredient 100.00 g

Lactose 100.00 g

Corn starch 70.00 g

Talc 8.50 g

Calcium stearate 1.50 g

Hydroxypropylmethylcellulose 2.36 g

Shellac 0.64 g

Water q.s.

Dichloromethane q.s.

The active ingredient, the lactose and 40 g of the corn starch are mixed and moistened and granulated with a paste prepared from 15 g of corn starch and water (with warming). The granules are dried, and the remainder of the corn starch, the talc and the calcium stearate are added and mixed with the granules. The mixture is compressed to give tablets (weight: 280 mg) and these are coated with a solution of the hydroxypropylmethylcellulose and the shellac in dichloromethane (final weight of the coated tablet: 283 mg).

Example 12: Tablets and coated tablets containing another compound of the formula I or a pharmaceutically acceptable salt of a compound of the formula I, for example as in one of Examples 1 to 9, can also be prepared in an analogous manner to that described in Examples 10 and 11. Pharmacological Experiments

Endothelin(ET) receptor binding assay

The binding affinity to the ET receptor of the compounds of the present invention is determined according to the method described below (published in Takagi et al. (1995) J. Biol. Chem., 270, 10072-10078).

ET-1 and ET-3 were purchased from Peptide Institute Inc. (Osaka, Japan), and [¹²⁵I]ET-1 (-74 TBq/mmol) was from Amersham International (Buckinghamshire, U.K.).

Human ETA or ETβ receptors are stably expressed in CHO (Chinese hamster ovary) cells, and plasma membranes having the ETA or ETβ receptor are prepared from these cells. The membranes (-0.04 mgΛube, for ETA receptor binding and -0.3 mg/tube for ETβ receptor binding) are incubated at 37°C for 4 hours and 2 hours for ETA and ETβ, respectively, with 10 pM [¹²⁵I]ET-1 in the absence or presence of various amounts of nonlabeled ligands in a total volume of 1 ml of 20 mM HEPES (pH 7.4), containing 145 mM NaCI, 5 mM KCl, 3 mM MgCl2, 1 mM EGTA, 1 mg/ml bovine serum albumin, and 0.2 mg/ml bacitracin. After the incubation, unbound [¹²⁵I]ET-1 is separated by centrifugation at 20,000 x g for 20 min at 4°C followed by aspiration of the supernatant. The radioactivity in the membrane pellet is measured in Wallac-1470 Wizard autogamma counter (Pharmacia). Nonspecific binding is defined as membrane-associated radioactivity in the presence of saturating concentrations of ET-1 or ET-3 (100 nM). Nonspecific binding is subtracted from the total binding and the difference is defined as specific binding. Total binding is always less than 10 % of the total radioactivity added.

By Scatchard analysis, the ETA receptor shows an apparant dissociation constant (Kd) of 5.9 pM and maximum binding sites (Bmax) of 33.3 pmol/mg of protein, while the ETβ receptor has a Kd of 3.5 pM and Bmax of 1.0 pmol/mg of protein. From the inhibition curves for the binding of [¹²⁵I]ET-1 , the apparant affinity constant (Ki) of the test compounds is calculated as a parameter of the affinity for the ETA an ETβ receptors. Example for Final Products Ki for the ETA-receptor [nM] Ki for the ETβ-receptor [nM]

1 1.5 1.2

2 1.5 1.2

5 2.6 3.0

Claims

Patent Claims

1. A compound of formula I

^R1 (0 wherein (i) Ri represents 1 ,2,4-triazol-1-yl, R₂ represents methyl or hydroxy, R₃ represents methyl or hydroxy, and the asterix means that the chiral carbon atom to which said asterix is attached has the (D) or (D,L) configuration, or (ii) Ri represents isoxazol-5-yl, R₂ is methyl, R₃ is methyl, and the asterix means that the chiral carbon atom to which said asterix is attached has the (D) configuration; or a salt thereof.

2. A compound according to claim 1 of formula (la)

wherein Ri represents 1 ,2,4-triazol-1-yl or isoxazol-5-yl, or a pharmaceutically acceptable salt thereof.

3. A compound according to claim 1 or 2 selected from the group consisting of N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)-alanyl]- (L)-valineamide,

N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]-(D,L)- alanyl]-(L)-valineamide,

N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]-(D)- alanyl]-(L)-valineamide,

N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl-(D,L)- alanyl]-(L)-threonineamide,

N-butanesulfonyl-[N-(3-hydroxy-5-methylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1-yl)-phenyl]- (D,L)-alanyl]-(L)-valineamide,

N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1 -yl)-phenyl-(D)- alanyl]-(L)-threonineamide, and

N-butanesulfonyl-[N- (3-hydroxy-5-methylbenzoyl)-N-methyl-3-[4-(1 ,2,4-triazol-1 -yl)-phenyl]-

(D)-alanyl]-(L)-valineamide, or, in each case, a pharmaceutically acceptable salt thereof.

4. A compound according to any one of claims 1-3 or of a pharmaceutically acceptable salt thereof for use in the treatment and prophylaxis of the human or animal body.

5. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to any one of claims 1 -3 or of a pharmaceutically acceptable salt thereof, if appropriate, in addition to a customary pharmaceutical adjunct.

6. Use of a compound according to any one of claims 1 -3 or of a pharmaceutically acceptable salt thereof for the manufacture of a pharmaceutical composition for the treatment of cerebral and coronary vasospasm, cerebral and cardiac ischemia, subarachnoidal haemorrhage, various types of hypertension, pulmonary hypertention, cardiac failure, Raynand-syndrome, diabetes, benign prostatic hyperplasia, atherosclerosis or restenosis due to denudation following angioplasty and also for the treatment of asthma, renal failure, dialysis, glomerular injury, hepatic failure, stomach and duodenal ulcer, ulcus cruris, various brain dysfunctions including migraine and delayed neuronal death, various cancers including prostate cancer, and occular diseases including glaucoma.

7. A method for the treatment of cerebral and coronary vasospasm, cerebral and cardiac ischemia, subarachnoidal haemorrhage, various types of hypertension, pulmonary hypertention, cardiac failure, Raynand-syndrome, diabetes, benign prostatic hyperplasia, atherosclerosis or restenosis due to denudation following angioplasty and also for the treatment of asthma, renal failure, dialysis, glomerular injury, hepatic failure, stomach and duodenal ulcer, ulcus cruris, various brain dysfunctions including migraine and delayed neuronal death, various cancers including prostate cancer, and occular diseases including glaucoma, comprising administering to a mammal in need of such treatment a therapeutic¬ ally effective amount of a compound according to any one of claims 1 -3 or a pharmaceutic¬ ally acceptable salt thereof.

8. A process for the manufacture of a compound according to claim 1 or of a salt thereof comprising a) reacting a compound of formula (lla)

R1 (lla) wherein Ri, R₃, and the asterix are as definied above, or a salt or a reactive acid derivative thereof with a compound of formula (lib)

wherein R₂ is as defined above.or a salt thereof; or, b) for the manufacture of a compound of formula (I) or a salt thereof, wherein the asterix means that the chiral carbon atom to which said asterix is attached has the (D) configuration, separating a mixture of isomers of formula (I), wherein the asterix means that the chiral carbon atom to which said asterix is attached has the (D,L) configuration and isolating the desired isomer,

and, if desired, free functional groups in starting material of each variant, with the exception of those participating in the reaction, being optionally in protected form, and any protecting groups present are removed; and, if desired, converting a free compound I obtainable according to the process into a salt or converting a salt of a compound I obtainable according to the process into the free compound I or into another salt.