IE990936L - Benzoic Acid Derivative - Google Patents

Abstract

(S) (+)-2-ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-1-butyl]-aminocarbonylmethyl]-benzoic acid and the addition salts thereof, have valuable pharmacological properties, in particular, an effect on the intermediate metabolism, more particularly the effect of lowering the blood sugar level. The pharmacological and pharmacokinetics of the (S)-enantiomer compounds are surprisingly and significantly superior to those of the racemate or of the (R)-enantiomer.

Description

IE 912519 1 56830/000.532 Benzoic acid derivative The present invention relates to (S) (+)-2 ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]amino carbonylmethyl]-benzoic acid, processes for its preparation and pharmaceutical compositions containing this compound.

EP—B—147 850 describes inter alia the racemate of 2-ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]-aminocarbonylmethyl]-benzoic acid (Code No.: AG-EE 388 ZW), a compound of formula and EP-B-207331 describes two polymorphous forms of this compound. This compound and the physiologically acceptable salts thereof have valuable pharmacological properties, in particular an effect on the intermediate metabolism, more particularly the effect of lowering the blood sugar level.

We have tested the two enantiomers of this compound, namely (S)(+)-2-ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]-aminocarbonylmethyl]-benzoic acid (Code No.: AG-EE 623 ZW) and (R)(-)-2-ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]aminocarbonyl methyl]benzoic acid (Code No.: AG-EE 624 ZW), for their CH CH C H iE 9125T9 blood sugar-lowering effect in female rats and, surprisingly, it was found that the (S)-enantiomer (AG-EE 62 3 ZW) is the active enantiomer in lowering the blood sugar level and its activity lasts for more than 6 hours in the rat.

On the basis of these findings in the rat, it appears appropriate to use exclusively AG-EE 62 3 ZW in humans, thereby reducing the dose by 50%, compared with the dose of AG-EE 388 ZW necessary to produce the same effect. This blood sugar-lowering effect together with a relatively long period of activity has also been found in humans. However, in the human studies it was also found that AG-EE 623 ZW has surprising pharmacokinetic properties which could not have been foreseen on the basis of the AG-EE 388 ZW data. Accordingly, AG-EE 62 3 ZW possesses surprising therapeutic advantages over the racemate AG-EE 388 ZW.

The surprising findings in humans included the following: (a) the AG-EE 623 ZW levels fall more rapidly towards zero than the AG-EE 388 ZW levels, even when the dosage is identical, a result which could not have been predicted in view of its relatively long period of activity? (b) in relation to the lowering of the blood sugar level, substantially lower plasma levels of AG-EE 623 ZW occur than might have been predicted by halving the dosage of AG-EE 388 ZW; and (c) the blood sugar lowering activity occurs more rapidly following the administration of AG-EE 623 ZW than following the administration of AG-EE 388 ZW.

The especially surprising difference between the two enantiomers is the fact that the active enantiomer, 912519 AG-EE 623 ZW, in spite of having a relatively long period of activity, is eliminated more rapidly than the inactive enantiomer, AG-EE 624 ZW, as demonstrated by Figures 1 and 2 hereto. These figures provide graphs of the plasma concentrations of AG-EE-624 ZW (filled squares) and AG-EE-62 3 ZW (open triangles) against time following 1.Omg i.v. administration of AG-EE-388 ZW to 12 volunteer male test subjects (Figure 1) and after 1.0 mg p.o. (in solution) administration of AG-EE-388 ZW to 12 volunteer male test subjects (Figure 2). Therefore, following the administration of the racemate, the inactive enantiomer, AG-EE 624 ZW, is present not only as an unnecessary additive in plasma concentrations which are just as high as those of the active enantiomer, AG-EE 62 3 ZW, but indeed and particularly surprisingly achieves higher and longer-lasting levels. The effect of this, e.g. following administration of a tablet containing 2 mg of AG-EE 388 ZW compared with administration of a tablet containing 1 mg of AG-EE 623 ZW to 12 and 6 test subjects, respectively, is that the maximum concentrations are 84 ± 25 and 28 ± 18 ng/ml, respectively, the concentrations after 4 hours are 19 ± 8 and 0.7 ± 1.0 ng/ml, respectively, after 5 hours 13 ± 6 and 0.3 ± 0.7 ng/ml, respectively, and after 6 hours 10 ± 6 and 0.3 ± 0.7 ng/ml, respectively.

The surprisingly quick onset of the lowering of the blood sugar level by AG-EE 62 3 ZW, compared with AG-EE 388 ZW, is particularly advantageous for diabetics, since the rapid onset results in optimum control of the disease.

Thus, compared with the administration of AG-EE 388 ZW, the surprising advantage of the administration of AG-EE 623 ZW is that unnecessarily high and long-lasting levels of the substance in the body are avoided, which IE 912519 is of major importance in long term therapy, such as that of diabetic mellitus.

Human studies have shown that the new (S)-enantiomer, namely (S)(+)-2-ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]aminocarbonylmethyl]-benzoic acid, as a vehicle of blood sugar-lowering activity, is far superior to AG-EE 388 ZW, due to its surprisingly rapid elimination from the blood, which was not foreseeable in view of its relatively long duration of activity. Such superior qualities go far beyond the "normal" advantage of an enantiomer over its racemate, namely that of halving the dose.

Thus, according to one aspect the present invention provides the new compound (S)(+)-2-ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]- aminocarbonylmethyl]-benzoic acid or an (S)(+)-2-ethoxy-4-[N-[l-(2-piperidino-phenyl)-3-methyl-l-butyl]-aminocarbonylmethyl]-benzoic acid which is substantially optically pure, e.g. having an optical purity of at least ee = 95%, preferably 98 to 100%, and the addition salts thereof, and more particularly for pharmaceutical use the physiologically acceptable addition salts thereof with inorganic or organic acids or bases.

According to a further aspect the invention also provides a process for the preparation of the compound of the invention, said process comprising at least one of the following steps: a) reacting the (S)-amine of formula I !E 912519 ch3 ch5 ch c / h n h •N (i) with a carboxylic acid of formula II (II) (wherein W represents an optionally protected carboxy group) or with a reactive derivative thereof, optionally prepared in the reaction mixture and, if necessary, subsequently cleaving any protecting group used; b) cleaving an (S)-compound of formula III IE 912519 (mi (wherein A represents a group which may be converted into a carboxy group by hydrolysis, thermolysis or hydrogenolysis); c) reacting an (S)-compound of formula IV (IV) (wherein W1 represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group) with a compound of formula V Z - CH2 - CH3 (V) (wherein Z represents a nucleophilic leaving group such as a IE 912519 7 halogen atom or a sulphonyloxy group, or, together with the adjacent hydrogen atom represents a diazo group) optionally followed by hydrolysis or hydrogenolysis; d) enantioselectively reducing a compound of formula VI (wherein W' represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group, and Y represents a group of formula (VI) optionally followed by hydrolysis; e) oxidising an (S)-compound of formula VII ch (VII) iE 912519 (wherein W" represents a group which may be converted into a carboxy group by oxidation); f) separating a mixture comprising an amount of the (S)-enantiomer of formula VIII (VIII) and an amount of the (R)-enantiomer of formula (IX) 3 .CHj 0CH,CH, (IX) (wherein W represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group), preferably a 50/50 mixture thereof, via the diastereomeric adducts, complexes or salts thereof, and followed if necessary by hydrolysis or hydrogenolysis; g) converting an (S)-enantiomer thus obtained, having an optical purity of, preferably, at least 90%, into an 912519 (S)-enantiomer having an optical purity of at least 95%, preferably 98 to 100%, by fractional crystallisation; and h) converting an (S)-enantiomer thus obtained into an addition salt thereof or an addition salt of the (S)-enantiomer into the free (S)-enantiomer.

Reactive derivatives of a compound of formula II include, for example, the esters thereof such as the methyl, ethyl and benzyl esters, the thioesters thereof such as the methylthio and ethylthioesters, the halides thereof such as acid chloride, and the anhydrides and imidazolides thereof.

The reaction of step (a) may conveniently be carried out in a solvent such as methylene chloride, chloroform, carbon tetrachloride, ether, tetrahydrofuran, dioxane, benzene, toluene, acetonitrile or dimethylformamide, optionally in the presence of an acid-activating agent or a dehydrating agent, e.g. in the presence of ethylchloro-formate, isobutylchloroformate, thionylchloride, phosphorus trichloride, phosphorus pentoxide, N,N'-dicyclohexylcarbodiimide, N,N1 -dicyclohexylcarbodi-imide/N-hydroxysuccinimide, N,N'-carbonyldiimidazole, N,N1-thionyldiimidazole or triphenylphosphine/carbon tetrachloride, or an agent which activates the amino group, e.g. phosphorus trichloride, and optionally in the presence of an inorganic base such as sodium carbonate or a tertiary organic base such as triethylamine or pyridine which may simultaneously serve as solvent, at temperatures between -25 and 250°C, preferably at temperatures between -10°C and the boiling temperature of the solvent used. The reaction may also be carried out without a solvent and moreover any water formed during the reaction may be removed by azeotropic distillation, e.g. by heating with 912519 toluene using a water separator, or by the addition of a drying agent such as magnesium sulphate or a molecular sieve.

If necessary, the subsequent cleaving of a protecting group used in step (a) is preferably carried out by hydrolysis, conveniently either in the presence of an acid such as hydrochloric, sulphuric, phosphoric, trifluoroacetic or trichloroacetic acid or in the presence of a base such as sodium hydroxide or potassium hydroxide, in a suitable solvent such as water, methanol, methanol/water, ethanol, ethanol/water, water/isopropanol or water/dioxane at temperatures between -10 and 120°C, e.g. at temperatures between ambient temperature and the boiling temperature of the reaction mixture.

A tert.-butyl group used as protecting group may also be cleaved thermally, optionally in an inert solvent such as methylene chloride, chloroform, benzene, toluene, tetrahydrofuran, dioxane or glacial acetic acid and preferably in the presence of a strong acid such as trifluoroacetic, hydrobromic, p-toluenesulphonic, sulphuric, phosphoric or polyphosphoric acid.

A benzyl group used as protecting group may also be cleaved hydrogenolytically in the presence of a hydrogenation catalyst such as palladium/charcoal in a suitable solvent such as methanol, ethanol, ethanol/water, glacial acetic acid, ethyl acetate, dioxane or dimethylformamide.

For reagents of formula III used in step (b), examples of hydrolysable groups include functional derivatives of the carboxy group such as optionally substituted amides, esters, thioesters, orthoesters, iminoethers, amidines and anhydrides, nitrile and tetrazolyl groups, and 912519 optionally substituted 1,3-oxazol-2-yl and 1,3-oxazolin-2-yl groups, examples of thermolytically cleavable groups include esters with tertiary alcohols, e.g. tert.butylester, and examples of hydrogenolytically cleavable groups include aralkyl groups, e.g. a benzyl group.

The hydrolysis of step (b) may conveniently be carried out either in the presence of an acid such as hydrochloric, sulphuric, phosphoric, trifluoroacetic or trichloroacetic acid or in the presence of a base such as sodium hydroxide or potassium hydroxide, in a suitable solvent such as water, water/methanol, ethanol, water/ethanol, water/isopropanol or water/dioxane at temperatures between -10 and 12 0°C, preferably at temperatures between ambient temperature and the boiling temperature of the reaction mixture.

If A in a compound of formula III represents a nitrile or aminocarbonyl group, these groups may be converted into a carboxy group by means of 100% phosphoric acid at temperatures between 100 and 180°C, preferably at temperatures between 120 and 160°C, or using a nitrite, e.g. sodium nitrite, in the presence of an acid such as sulphuric acid, whilst the latter may conveniently be used as solvent at the same time, at temperatures between 0 and 50°C.

If A in a compound of formula III represents, for example, a tert.butyloxycarbonyl group, the tert.butyl group may also be cleaved thermally, optionally in an inert solvent such as methylene chloride, chloroform, benzene, toluene, tetrahydrofuran, dioxane or glacial acetic acid and preferably in the presence of a strong acid such as trifluoroacetic acid, hydrobromic acid, p-toluenesulphonic acid, sulphuric acid, phosphoric acid or polyphosphoric acid, at temperatures between 0 and IE 912519 100°C, preferably at temperatures between 20°C and the boiling temperature of the solvent used.

If A in a compound of formula III represents, for example, a benzyloxycarbonyl group, the benzyl group may also be cleaved hydrogenolytically in the presence of a hydrogenation catalyst such as palladium/charcoal in a suitable solvent such as methanol, ethanol, methanol/water, ethanol/water, glacial acetic acid, ethyl acetate, dioxane or dimethylformamide, preferably at temperatures between 0 and 50°C, e.g. at ambient temperature and under a hydrogen pressure of from 1 to 5 bar.

The reaction of step (c) may conveniently be carried out with a corresponding halide, sulphonic acid ester or sulphuric acid diester, e.g. with ethyl bromide, ethyl iodide, diethylsulphate, ethyl p-toluenesulphonate or ethyl-methanesulphonate, or with diazoethane, optionally in the presence of a base such as sodium hydride, potassium carbonate, sodium hydroxide, potassium tert.butoxide or triethylamine, preferably in a suitable solvent such as acetone, diethylether, tetrahydrofuran, dioxane, pyridine or dimethylformamide at temperatures between 0 and 100°C, preferably at temperatures between 20 and 50°C.

If W in a compound of formula IV represents a carboxy group, this can be converted into the corresponding ester compound.

If necessary, the subsequent hydrolysis of step (c) is carried out either in the presence of an acid such as hydrochloric, sulphuric, phosphoric, trifluoroacetic or trichloroacetic acid or in the presence of a base such as sodium hydroxide or potassium hydroxide in a suitable solvent such as water, methanol, methanol/water, 912519 ethanol, ethanol/water, water/isopropanol or water/dioxane at temperatures between -10 and 120°C, e.g. at temperatures between ambient temperature and the boiling temperature of the reaction mixture.

The subsequent hydrogenolysis may also be carried out in the presence of a hydrogenation catalyst such as palladium/charcoal in a suitable solvent such as methanol, ethanol, ethanol/water, glacial acetic acid, ethyl acetate, dioxane or dimethylformamide under a hydrogen pressure of from 1 to 10 bar.

The reduction of step (d) is preferably carried out with hydrogen in the presence of a chiral hydrogenation catalyst in a solvent such as methanol, ethanol, isopropanol, ethyl acetate, dioxane, tetrahydrofuran, methanol/tetrahydrofuran, methanol/methylene chloride, ethanol/methylene chloride of isopropanol/methylene chloride at temperatures between 0 and 100"C, but preferably at temperatures between 20 and 50°C, under a hydrogen pressure of between 1 and 1000 bar, preferably between 5 and 100 bar, and conveniently with the addition of 0.1 to 5%, preferably 0.3 to 1%, of titanium(IV)tetraisopropoxide, preferably with the exclusion of oxygen from the surrounding atmosphere. The reduction is preferably carried out with the (Z)— form of a compound of formula VI.

Examples of chiral hydrogenation catalysts which may be used in step (d) include the corresponding metal ligand complexes such as Ru(OCO-CH3) 2[(S)-BINAP], Ru2C14[(S)~ BINAP]2 x N(C2H5)3, Rh[ (S)-BINAP-NBD]C104 or Rh[(-)-N0RPH0S-C0D]BF4. During the catalytic hydrogenation, a benzyloxycarbonyl group may simultaneously be reduced and converted into the carboxy group.

If necessary, the subsequent hydrolysis of step (d) may IE 912519 be carried out either in the presence of an acid such as hydrochloric, sulphuric, phosphoric, trifluoroacetic or tri-chloroacetic acid or in the presence of a base such as sodium hydroxide or potassium hydroxide in a suitable solvent such as water, methanol, methanol/water, ethanol, ethanol/water, water/isopropanol or water/dioxane at temperatures between -10 and 120°C, e.g. at temperatures between ambient temperature and the boiling temperature of the reaction mixture.

For the reagent of formula VII used in step (e), examples of oxidisable W" groups include the formyl group and the acetals thereof, the hydroxymethyl group and the ethers thereof, and optionally substituted acyl groups such as acetyl, chloroacetyl, propionyl, malonic acid-(l)-yl and malonic ester-(l)-yl groups.

The reaction of step (e) may be carried out with an oxidising agent in a suitable solvent such as water, glacial acetic acid, methylene chloride, dioxane or glycoldimethylether at temperatures between 0 and 100°C, preferably at temperatures between 20°C and 50°C. However, the reaction is preferably carried out with silver oxide/sodium hydroxide solution, manganese dioxide/acetone or methylene chloride, hydrogen peroxide/sodium hydroxide solution, bromine or chlorine/sodium or potassium hydroxide solution, chromium trioxide/pyridine or pyridinium chlorochromate.

The separation of step (f) is preferably carried out using column or HPL chromatography by forming the diastereomeric adducts or complexes on a chiral phase.

If necessary, the subsequent hydrolysis of step (f) may be carried out either in the presence of an acid such as hydrochloric, sulphuric, phosphoric, trifluoroacetic or trichloroacetic acid or in the presence of a base such IE 912519 as sodium hydroxide or potassium hydroxide in a suitable solvent such as water, methanol, methanol/water, ethanol, ethanol/water, water/isopropanol or water/dioxane at temperatures between -10 and 120°C, e.g. at temperatures between ambient temperature and the boiling temperature of the reaction mixture.

The subsequent hydrogenolysis may also be carried out in the presence of a hydrogenation catalyst such as palladium/charcoal in a suitable solvent such as methanol, ethanol, ethanol/water, glacial acetic acid, ethyl acetate, dioxane or dimethylformamide under a hydrogen pressure of from 1 to 10 bar.

A compound obtained in step (f) may, if necessary, be converted by recrystallisation into a compound with a higher enantiomeric purity, crystallisation from ethanol/water (2/1 by volume) producing the high melting form with a melting point of 130-131°C, and crystallisation from petroleum ether/toluene (5/3 by volume) producing the low-melting form with a melting point of 99—101°C.

The (S)-enantiomer obtained according to the invention may, if desired, be converted into the addition salts thereof, more particularly, for pharmaceutical use, into the physiologically acceptable salts thereof with inorganic or organic acids or bases. Examples of suitable acids for this purpose include hydrochloric, hydrobromic, sulphuric, phosphoric, lactic, citric, tartaric, succinic, maleic and fumaric acids and examples of suitable bases include sodium hydroxide, potassium hydroxide, calcium hydroxide, cyclohexylamine, ethanolamine, diethanolamine, triethanolamine, ethylenediamine and lysine.

Some of the compounds of formulae I to IX used as IE 912519 starting materials are known from the literature. Otherwise these compounds may be obtained by methods known per se.

The (S)-amine of formula I may, for example, be obtained from the corresponding racemic amine: by racemate cleaving, e.g. by means of fractional crystallisation of the diastereomeric salts with suitable optically active acids, preferably with N-acetyl-L-glutamic acid, and if necessary recrystallisation and subsequent decomposition of the salts, or by column or HPL-chromatography on chiral phases, optionally in the form of an acyl derivative, or by forming diastereomeric compounds, then separating and subsequently cleaving them.

Additionally, the (S)-amine of formula I may be prepared: by enantioselective reduction using hydrogen in the presence of a suitable chiral hydrogenation catalyst, starting from a corresponding N-acyl-ketimine or enamide, conveniently with the addition of 0.1 to 5% titanium tetraisopropoxide, optionally with subsequent cleaving of the acyl group such as the formyl or acetyl group, or by diastereoselective reduction of a corresponding ketimine or hydrazine chirally substituted at the nitrogen atom, using hydrogen in the presence of a suitable hydrogenation catalyst, conveniently with the addition of 0.1 to 5% titanium tetraisopropoxide, and optionally followed by cleaving of the chiral auxiliary IE 912519 group, e.g. the (S)-1-phenethyl group, by catalytic hydrogenolysis, or by diastereoselective addition of a corresponding organometallic compound, preferably a Grignard or lithium compound, to a corresponding aldimine chirally substituted at the nitrogen atom, optionally with the addition of 0.1 to 10% titanium tetraisopropoxide, subsequent hydrolysis and optional separation of the resulting diastereomers and subsequent cleaving of the chiral auxiliary group, e.g. the (R)-1-phenethyl group by catalytic hydrogenolysis, and if necessary the (S)-amine may be obtained in a higher enantiomeric purity by salt formation with suitable optically active acids, preferably with N-acetyl-L-glutamic acid, and if necessary single or multiple recrystallisation and subsequent decomposition of the salt.

Compounds of formulae III, IV and VII used as starting materials may be obtained by reacting the (S)-amine of formula I with a corresponding carboxylic acid or a reactive derivative thereof and optionally subsequently splitting off any protecting group used.

The compounds of formula VI used as starting materials may be obtained by acylating corresponding imino compounds or the organometallic complexes thereof with a corresponding carboxylic acid or with a reactive derivative thereof with optional subsequent cleaving of an ester group.

The new (S)-enantiomer is virtually non-toxic; for example, after a single administration of 1000 mg/kg p.o. (suspension in 1% methylcellulose) to 5 male and 5 female rats, no animals died within the observation 912519 period of 14 days.

In view of its pharmacological and pharmacokinetic properties, the (S)-enantiomer prepared according to the invention (AG-EE 623 ZW) and the physiologically acceptable salts thereof are suitable for the treatment of diabetes mellitus. For this purpose, AG-EE 623 ZW or the physiologically acceptable salts thereof, optionally combined with other active substances, may be incorporated in conventional galenic preparations such as plain or coated tablets, capsules, powders, suppositories, suspensions or injectable solutions. The single dose for adults is 0.1 to 20 mg, preferably 0.25 to 5 mg, especially 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 or 5.0 mg, once, twice or three times a day.

Thus in a further aspect the present invention provides a pharmaceutical composition comprising as active ingredient the (S)-enantiomer or a physiologically acceptable addition salt thereof together and at least substantially free from other isomers of said active ingredient with at least one pharmaceutical carrier or excipient.

In a still further aspect the present invention provides the use of the (S)-enantiomer or a physiologically acceptable addition salt thereof for the manufacture of a therapeutic agent for the treatment of diabetes mellitus.

In a still yet further aspect the present invention provides a method of treatment of the human or non-human animal body to combat diabetes mellitus, said method comprising administering to said body the (S)-enantiomer or a physiologically acceptable addition salt thereof.

In another aspect the present invention provides new IE 912519 compounds of formulae I, III, IV and VII which are valuable intermediate products for preparing the new (S)-enantiomer, and the addition salts thereof with inorganic or organic acids.

The following non-limiting Examples are provided to illustrate the invention. Unless otherwise specified all percentages and ratios given are by weight.

Example A (S)-1-(2-Piperidino-phenyl)-3-methyl-l-butylamine A stirred solution of 122 g (0.495 mol) of racemic l-(2-piperidino-phenyl)-3-methyl-l-butylamine in 1000 ml of acetone is mixed with 93.7 g (0.495 mol) of N-acetyl-L-glutaminic acid. The mixture is refluxed over a vapour bath and methanol is added in batches (a total of about 80 ml) until a clear solution is obtained. After this has been left to cool and stand overnight at ambient temperature, the crystals obtained are removed by suction filtering, washed twice with 200 ml of cold acetone at -15°C and then dried. The product obtained [98.9 g; melting point: 163-166°C; [a]p° = + 0.286° (c = 1 in methanol)] is recrystallised from 1000 ml of acetone with the addition of 200 ml of methanol, thereby producing the (S)-1-(2-piperidino-phenyl)-3-methyl-l-butylamine as the addition salt of N-acetyl-L-glutaminic acid.

Yield: 65.1 g (60.4% of theory), Melting point: 168-171°C Calculated: C 63.42 H 8.56 N 9.65 Found: 63.64 8.86 9.60 [a]j;0= + 0.357° (c = 1 in methanol) The free amine is obtained as an oil by liberation, for example, with a sodium hydroxide or ammonia solution, IE 912519 extraction with, for example, toluene, ether, ethylacetate or methylene chloride, and drying, filtering and evaporation of the extract _in vacuo.

The (S)-configuration of the amine was demonstrated as follows: Reaction of the amine with (S')-1-phenethylisocyanate in ether to obtain the corresponding urea derivative [melting point: 183-184°C; [a]p° = - 2.25° (c = 1 in methanol)], growing crystals from ethanol/water (8/1 by volume) and subsequent X-ray structural analysis showed the (S,S1)-configuration for the urea derivative and consequently the (S)-configuration for the amine used.

Enantiomeric purity was determined as follows: 1. Acetylation of a sample of the amine with 1.3 equivalents of acetic anhydride in glacial acetic acid at 20°C overnight. 2. Investigation of the N-acetyl derivative (melting point: 128-132°C) by HPLC on a chiral phase HPLC column made by Baker, in which (S)-N-(3,5-dinitrobenzoyl)-2-phenyl-glycine is covalently bonded to aminopropyl silica gel (particle size 5 nm, spherical, pore size 60 A; column length: 250 mm with internal diameter 4.6 mm; eluant: n-hexane/isopropanol (100/5 by volume); flow rate: 2 ml/minute; temperature: 20°C; UV-detection at 254 nm.) Found: peak 1(R): peak 2(S) = 0.75%: 99.25%, ee (enantiomeric excess) = 98.5% (S) .

The (S)-amine may be converted into the dihydrochloride hydrate thereof using ethereal hydrogen chloride solution.

Melting point: 135-145°C (decomposition) Calc. (x H20) : C 56.99 H 8.97 N 8.31 Cl 21.02 Found: 56.85 8.93 8.38 21.25 [a]p° = + 26.1° (c = 1 in methanol) 912519 Example B N-Acetyl-N-[1-(2-piperidino-phenyl)-3-methyl-l-buten-l-yl]-amine At ambient temperature, 4.7 ml (81.8 mMol) of glacial acetic acid, 25.7 g (98.2 mMol) of triphenylphosphine, 34.2 ml (245 mMol) of triethylamine and 7.9 ml (81.8 mMol) of carbon tetrachloride are added to a solution of 20 g (81.8 mMol) of freshly prepared isobutyl-(2-piperidino-phenyl)-ketimine in 200 ml of acetonitrile and the resulting mixture is stirred for 18 hours at ambient temperature. It is then evaporated down in vacuo and distributed between ethyl acetate and water. The organic extract is dried and filtered and evaporated down rn vacuo. The evaporation residue is purified by column chromatography on silica gel (toluene/ethyl acetate = 10/1 by volume), eluting first the (E)-form and then the (Z)-form. fE)-form: Yield: 6.1 g (26% of theory), Melting point: 135-137°C (ethylacetate/petroleum ether) Calculated: C 75.48 H 9.15 N 9.78 Found: 75.47 9.35 9.70 (Z)-form: Yield: 3.1 g (13% of theory), Melting point: 140-143"C (ethylacetate) Calculated: C 75.48 H 9.15 N 9.78 Found: 75.56 9.30 9.79 912519 Example C N-Acetyl-N-[1-(2-piperidino-phenyl)-3-methyl-l-buten-l-yl ]-amine 17 ml (0.18 mol) of acetic anhydride are added dropwise, at an internal temperature of 0°C, to a stirred solution of 44 g (0.18 mol) of freshly prepared isobutyl-(2-piperidino-phenyl)-ketimine in 440 ml of toluene. The mixture is stirred for a further 3 hours at 0°C and for 15 hours at ambient temperature, then evaporated down in vacuo, the evaporation residue is dissolved in ethyl acetate and extracted several times with aqueous sodium hydrogen carbonate solution. The organic phase is dried, filtered and evaporated down in vacuo. The evaporation residue is purified by column chromatography on silica gel (toluene/ethyl acetate = 5/1 by volume), eluting first the (E)-form and then the (Z)-form. CE)-form: Yield: 3.0 g (5.8% of theory), (Z)-form: Yield: 17.8 g (34.5% of theory), Melting point: 139-141°C (ethyl acetate) Calculated: C 75.48 H 9.15 N 9.78 Found: 75.68 8.99 9.86 Example D N-Acetyl-N-[(S)-1-(2-piperidino-phenyl)-3-methyl-l-butyl ]-amine 0.57 g (1.99 mMol) of (Z)-N-acetyl-N-[1-(2-piperidino-phenyl) -3-methyl-l-buten-l-yl] -amine, melting point 139 — 141°C, are dissolved in 10 ml of degassed solvent mixture (methanol/methylene chloride = 5/1 by volume) under an Argon atmosphere and added to a solution of 16.8 mg (1 mol %) of the NOYORI-catalyst Ru(0-acetyl)2[(S)-BINAP] (prepared from [Ru(COD)Cl2]n with (S)-BINAP [= (S)-2 , 2 1-bis (diphenylphosphino)-1, l-i-binaphthyl], triethylamine and sodium acetate), and 3.4 mg (0.5 mol %) of titanium tetraisopropoxide in 10 ml of degassed solvent mixture (methanol/methylene chloride = 5/1 by volume). The reaction mixture is drawn into an autoclave which is evacuated at 10"2 mbar. It is flushed several times with hydrogen at 4 bar and the mixture is then hydrogenated at 30°C under 100 bar until the hydrogen uptake has ceased (170 hours). Then the reddish-brown solution is evaporated down in vacuo. the evaporation residue is refluxed with 3 0 ml of n-hexane and filtered hot to remove any insoluble matter. When the filtrate cools, crystallisation occurs.

Yield: 0.31 g (54% of theory), Melting point: 127-131°C enantiomeric purity: ee = 82% (S) [HPLC method: see Example A]. 14% of the racemic N-acetyl-amine of melting point 154-156°C can be obtained from the insoluble matter obtained when boiling with 30 ml of n-hexane, by further decoction with n-hexane, filtration and crystallisation from the hexane solution.

Example E (S)-1-(2-Piperidino-phenyl)-3-methyl-l-butylamine 1 g (3.47 mMol) of N-acetyl-N-[(S)-1-(2-piperidino-phenyl )-3-methyl-l-butyl]-amine (melting point: 128-133°C; ee = 99.4%] are refluxed in 10 ml of concentrated hydrochloric acid for 5.5 hours, then cooled and poured into a mixture of concentrated ammonia and ice. The mixture is extracted twice with ethyl acetate, the organic phase is washed with water, dried 912519 and filtered and then evaporated down in vacuo.

Yield: 0.84 g (98.8% of theory) oily amine.

By re-acetylation with 0.42 ml (1.3 equivalents)-of acetic anhydride in 8.4 ml of glacial acetic acid overnight at ambient temperature, evaporation in vacuo. distribution of the evaporation residue between ethyl acetate and saturated aqueous sodium bicarbonate solution then drying, filtering and evaporation of the organic extract in vacuo. 0.83 g (84.7% of theory) of N-acetyl-N-[(S)-1-(2-piperidino-phenyl)-3-methyl-l-butyl]-amine are obtained (melting point: 130-132°C; ee = 99.4%).

Example F Ethyl 2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-1-buten-l-yl)-aminocarbonylmethyl]-benzoate Prepared from isobutyl-(2-piperidino-phenyl)-ketimine and 3-ethoxy-4-ethoxycarbonyl-phenylacetic acid analogously to Example B. Purification by column chromatography on silica gel (toluene/acetone = 10/1 by volume), eluting first the (E)-form and then the (Z)-form.

(E)-form: Yield: 4% of theory, Melting point: 101-103°C Calculated: C 72.77 H 8.00 N 5.85 Found: 72.74 7.78 5.86 (Z)-form: Yield: 28.1% of theory, Melting point: 124-127°C (petroleum ether/toluene = 5/1 by volume) Calculated: C 72.77 H 8.00 N 5.85 Found: 72.90 7.86 5.83 912519 Example G N-[(S1)-1-phenethyl]-N-[(S)-l-(2-piperidino-phenyl)-3-methyl-l-butyl]-amine 17 g (49 mMol) of N-[(S')-1-phenethyl]-isobutyl-(2-piperidino-phenyl)-ketimine, boiling point 150-155 ° C/0.3 torr [prepared from isobutyl-(2-piperidino-phenyl)-ketone and (S')-1-phenethyl-amine (made by Fluka, ee = 99.6%) in toluene + triethylamine by dropwise addition of a solution of titanium tetrachloride in toluene] are dissolved in 170 ml of anhydrous ethanol. 1.7 g of titanium tetraisopropoxide and 8 g of Raney nickel are added and the mixture is hydrogenated at 50°C under 2 00 bar of hydrogen. After 2 0 hours a further 8 g of Raney nickel are added and the mixture is hydrogenated for a further 52 hours under the same conditions. The catalyst is filtered off over a layer of Celite on a G3-frit and the filtrate is evaporated down iri vacuo.

Yield: 13.1 g (76.6% of theory), Boiling point: 152°C/0.2 torr Calculated: C 82.23 H 9.78 N 7.99 Found: 82.00 10.03 7.74 [a]p°= - 55.3° (c = 1.1 in methanol) The diastereomeric purity is determined by HPLC on a Lichrosorb RP18 HPLC column made by E. Merck (Germany); column length: 2 50 mm with an internal diameter of 4 mm; particle size: 7 urn. Eluant: methanol/dioxane/0.1% aqueous sodium acetate solution, adjusted to pH 4.05 with acetic acid (135/60/5 by volume); temperature: 2 3°C; UV-detection at 2 54 nm.

Found: peak 1(S,S'): peak 2(R,S') = 98.4%: 1.4%, de (diastereomeric excess) = 97.0% (S,S').

IE 912519 Example H (S)-1-(2-Piperidino-phenyl)-3-methyl-l-butylamine 12.5 g (36 mMol) of N-[(S')-1-phenethyl]-N-[(S)-1-(2-piperidino-phenyl)-3-methyl-l-butyl]-amine with a de of 97.0% (S,S') are dissolved in 125 ml of water and 3.6 ml of conc. hydrochloric acid. 1.3 g of (10%) palladium/charcoal are added and the mixture is hydrogenated at 50°C under 5 bar of hydrogen. After the hydrogen uptake has ended (10 hours) the mixture is filtered over a layer of Celite to remove the catalyst. The filtrate is made alkaline with conc. ammonia with the addition of ice and extracted with ethyl acetate. The organic extract is dried and filtered and evaporated down in vacuo.

Yield: 6.4 g (72.1% of theory), Boiling point: 115-117°C/0.4 torr Enantiomeric purity: ee = 93.5% (S) [HPLC method (after previous acetylation): see Example A].

Example I N-[(R1)-1-phenethyl]-N-[(S)-1-(2-piperidino-phenyl)-3-methyl-l-butyl]-amine A solution of 2 g (6.84 mMol) of N-[(R1)-1-phenethyl]-(2-piperidino-benzaldimine) [prepared from equimolar amounts of 2-piperidino-benzaldehyde and (R')-l-phenethylamine by standing overnight at ambient temperature and subsequent drying with sodium sulphate in ether solution] in 2 0 ml of anhydrous tetrahydrofuran is added dropwise to a solution of 27.4 mMol (4 equivalents) of isobutyl-magnesium bromide in 22 ml of anhydrous tetrahydrofuran, which is stirred in a bath at 60°C. After 18 hours the bath temperature is increased 912519 to 80°C and a further 2 equivalents of isobutyl-magnesium bromide in 11 ml of tetrahydrofuran are added. After 12 hours stirring at 80°C 2 equivalents of isobutyl-magnesium bromide solution are added onee again. After about 90 hours at 80°C the mixture is cooled, excess conc. hydrochloric acid is added and the resulting mixture is evaporated to dryness in a water jet vacuum. The evaporation residue is dissolved in water and made alkaline with conc. ammonia. It is extracted with ether, the organic extract is dried over sodium sulphate, filtered and evaporated in vacuo. The evaporation residue is purified by column chromatography on silica gel (toluene/acetone = 95/5 by volume).

Yield: 0.20 g (8.3% of theory), Melting point: < 20°C The diastereomeric purity is determined by HPLC as in Example G.

Found: peak 1(R,R'): peak 2(S,R') = 4.4%:95.6%, de (diastereomeric excess) = 91.2% (S,R').

In an analogous mixture with 2.0 g of the Schiff's base and a total of 6 equivalents of isobutyl-magnesium bromide in toluene/tetrahydrofuran (4/1 by volume) and with the addition of 5% titanium(IV)-tetraisopropoxide and heating for 60 hours at 100°C in a glass tank, a yield of 5% was achieved with a de of 97.6% (S,R').

Example K (S)-1-(2-Piperidino-phenyl)-3-methyl-l-butylamine A solution of 0.15 g (0.428 mMol) of N-[(R')-1-phenethyl]-N-[(S)-1-(2-piperidino-phenyl)-3-methyl-1-butyl]-amide (de = 91.2%), 0.47 ml (0.47 mMol) of 1N-hydrochloric acid and 1.5 ml of water is hydrogenated in the presence of 20 mg of 10% palladium/charcoal for 5 hours at 50°C under 3.4 bar of hydrogen. The mixture is 912519 filtered over kieselguhr, made alkaline with conc. ammonia and extracted with ethyl acetate. The extract is dried, filtered and evaporated in vacuo.

Yield: 0.066 g (62.8% of theory), Melting point: < 20°C Enantiomeric purity: ee = 87.6% (S) [HPLC method (after previous acetylation): see Example A].

Example 1 Ethyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate 0.48 g (1.91 mMol) of 3-ethoxy-4-ethoxycarbonyl-phenylacetic acid, 0.60 g (2.29 mMol) of triphenyl-phosphine, 0.80 ml (5.73 mMol) of triethylamine and 0.18 ml (1.91 mMol) of carbon tetrachloride are added successively to a solution of 0.47 g (1.91 mMol) of (S)-3-methyl-l-(2-piperidino-phenyl)-1-butylamine (ee = 98.5%) in 5 ml of anhydrous acetonitrile and the resulting mixture is stirred for 20 hours at ambient temperature. It is then evaporated down in vacuo and distributed between ethyl acetate and water. The organic extract is dried and filtered and evaporated down in vacuo. The evaporation residue is purified by column chromatography on silica gel (toluene/ethyl acetate = 10/1 by volume).

Yield: 0.71 g (77.3% of theory), Melting point: 110-112°C Calculated: C 72.47 H 8.39 N 5.83 Found: 72.29 8.42 5.80 The enantiomeric purity is determined by HPLC on a chiral phase HPLC column made by Baker, in which (S)-N-3,5—dinitrobenzoyl-leucine is covalently bound to aminopropyl silica gel (particle size: 5 fim, spherical, 60 A pore size; column length: 250 mm with an internal IE 912519 diameter of 4.6 mm; eluant: n-hexane/tetrahydro-furan/methylene chloride/ethanol (90/10/1/1 by volume); flow rate: 2 ml per minute; temperature: 20°C; UV detection at 242 nm).

Found: peak 1(R): peak 2(S) = 0.75%: 99.25%, ee = 98.5% (S).

Example 2 Ethyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate 2.77 g (11 mMol) of 3-ethoxy-4-ethoxycarbonyl-phenylacetic acid are added at ambient temperature to a solution of 2.71 g (11 mMol) of anhydrous (S)-3-methyl-1-(2-piperidino-phenyl)-1-butylamine (ee = 98.5%) in 30 ml of absolute toluene and the mixture is stirred until dissolved. Then 2.38 g (11.55 mMol) of N,N'-dicyclohexyl-carbodiimide are added and the mixture is stirred at ambient temperature. After 24 hours a further 0.54 g (2.14 mMol) of 3-ethoxy-4-ethoxycarbonyl-phenylacetic acid and 0.48 g (2.33 mMol) of N,N'~ dicyclohexylcarbodiimide are added and the mixture is stirred overnight. It is then cooled to an internal temperature of +5°C and suction filtered to separate the precipitate, which is washed once with 5 ml of toluene. The combined toluene filtrates are evaporated down in vacuo to a volume of about 10 ml. The resulting solution is heated over the steam bath and petroleum ether is added in batches thereto (total of 55 ml) until the turbidity remains. It is cooled in ice, whereupon crystallisation takes place. It is suction filtered and dried at 75°C/4 torr. The product obtained (4.57 g; melting point 111-112°C; ee = 98.9%) is suspended in 50 ml of petroleum ether. The mixture is heated over the steam bath and sufficient toluene is added in 912519 batches (8 ml in total) until a solution is obtained.

This is then cooled in ice and suction filtered to separate the crystals, which are dried at 75°C/4 torr.

Yield: 3.93 g (74.3% of theory), Melting point: 117-118°C Calculated: C 72.47 H 8.39 N 5.83 Found: 72.44 8.43 5.93 [a]p°= + 9.4° (c = 1.01 in methanol) Enantiomeric purity: ee = 99.9% [HPLC method: see Example 1] Example 3 (S)-2-Ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl )-aminocarbonylmethyl]-benzoic acid A solution of 3.79 g (7.88 mMol) of ethyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate (ee = 99.9%) in 37 ml of ethanol is stirred in a bath at 60°C and 10 ml (10 mMol) of IN sodium hydroxide solution are added. After 4 hours stirring at 60°C, 10 ml (10 mMol) of 1N-hydrochloric acid are added in the warm and the mixture is left to cool to ambient temperature. After inoculation and standing overnight, the mixture is cooled for a further hour in ice, with stirring. The crystals are separated by suction filtering and washed twice with 5 ml of water. They are then dried at 75°C up to a final temperature of l00°C/4 torr in a vacuum drying cupboard over phosphorus pentoxide.

Yield: 3.13 g (87.7% of theory), Melting point: 130-131°C (high-melting form) Calculated: C 71.64 H 8.02 N 6.19 Found: 71.48 7.87 6.39 [a]p°= + 7.45° (c = 1.06 in methanol) The enantiomeric purity is determined by HPLC on a IE 912519 chiral phase HPLC column made by ChromTech (Sweden) with an AGP(al-acid glycoprotein) phase; internal diameter: 4.0 mm; length: 100 mm; particle diameter: 5 jum. Temperature: 20°C; eluant: 0.1% aqueous KH2P04 solution (=A) + 20% acetonitrile (=B), gradient increase within 4 minutes to 4 0% (B); flow rate: 1 ml per minute; UV detection at 240 nm. Retention time (S)-enantiomer: 2.7 minutes; retention time (R)-enantiomer: 4.1 minutes. Found: (S):(R) = 99.85%: 0.15%, ee = 99.7% (S).

When a sample is recrystallised from ethanol/water (2/1 by volume) the melting point does not change. When a sample is heated in petroleum ether/toluene (5/3 by volume) the undissolved portion is filtered (melting point: 130—131°C) and the filtrate is rapidly cooled, the low melting form of the title compound is obtained, melting point 99-101°C.

Calculated: C 71.64 H 8.02 N 6.19 Found: 71.66 7.97 6.44 The low melting form and the high melting form differ in their infra-red KBr spectra but not in their infra-red solution spectra (methylene chloride).

If a sample of the low melting form is heated beyond its melting point a second melting point is observed at 127-13 0 ° C.

If a sample of the low-melting form is recrystallised from ethanol/water (2/1 by volume), the high melting form is obtained.

The high melting form and the low melting form were investigated by Differential Scanning Calorimetry (DSC) [Mettler apparatus, TA-300 system; measuring cell: DSC 20; made by Mettler, CH-8306 Greifensee, Switzerland] with the following results: IE 912519 Compound of Heating rate 10°K/min. Heating rate 3°K/min. Example 3 High melting Uniform melting peak form with melting tempera ture of 133 ° C; melting enthalpy: 100 J/g Uniform melting peak with melting tempera-of 132 ° C; melting enthalpy: 99.1 J/g Low melting form 1st peak at 57°C (very weak) 2nd peak at 78°C (weak) 3rd endothermic peak at 107°C; melting enthalpy: 55 J/g 4th endothermic peak at 132 ° C melting enthalpy: 2 5 J/g 1st peak at 54°C (very weak; endothermic) 2nd endothermic peak at 104 ° C. melting temperature 102 °C, melting enthalpy 52 J/g 3rd exothermic path of the base line by crystallisation of the substance melting at 104 ° C 4th endothermic peak at 131° C, melting temperature 130°C melting enthalpy 52 J/g Example 4 Ethyl (S)-2-ethoxy-4-[N-(l-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate 0.79 g (1.65 mMol) of ethyl (Z)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-buten-l-yl)-aminocarbonylmethyl] -benzoate, melting point 124-127"C, are dissolved in 10 ml of degassed solvent mixture (methanol/methylene chloride = 5/1) under an Argon atmosphere and added to a solution of 17 mg of the NOYORI-catalyst Ru(0- 912519 acetyl)2[ (S)-BINAP] (prepared from [Ru(COD)Cl2]n with (S)-BINAP [= (S)-2 , 21-bis-(diphenylphosphino)-1,1' -binaphthyl], triethylamine and sodium acetate) and 3 mg of titanium tetraisopropoxide in 10 ml of degassed solvent mixture (methanol/methylene chloride = 5/1 by volume). The reaction mixture is drawn into an autoclave evacuated at 10"2 mbar. This is flushed five times with hydrogen at 5 bar and finally hydrogenated at 30°C and 100 bar until the hydrogen uptake has ceased (154 hours). The reddish-brown solution is evaporated down in vacuo, the evaporation residue is dissolved in 80 ml of ether, filtered off from the undissolved brown flakes by means of activated charcoal and the resulting clear, bright yellow filtrate is evaporated down in vacuo. The evaporation residue (0.60 g) is refluxed in 60 ml of n-hexane and filtered hot to separate it from the insoluble matter. The filtrate is left to stand overnight at ambient temperature. The crystals which are precipitated are filtered off.

Yield: 0.45 g (56.7% of theory), Melting point: 131-133°C (after sintering from 120°C) Enantiomeric purity: ee = 39% (S) [HPLC method: see Example 1].

Example 5 Ethyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate 0.05 g (1.15 mMol) of 55% sodium hydride in oil are added to a solution of 0.68 g (1.15 mMol) of ethyl (S)-2-hydroxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl ) -aminocarbonylmethyl ] -benzoate [melting point: 125-126°C; [a]20 = + 12.87° (c = 1.01 in methanol)] in ml of anhydrous dimethylformamide and the mixture is stirred for 0.5 hours at ambient temperature. Then a solution of 0.12 ml (1.15 mMol) of ethyliodide in 2.5 ml IE 912519 of anhydrous dimethylformamide is added dropwise thereto and the mixture is stirred for 5 hours at ambient temperature. It is evaporated down rn vacuo. the residue is distributed between dilute sodium hydroxide solution and chloroform, the organic extract is dried, filtered and evaporated down in vacuo. The evaporation residue is purified by column chromatography on silica gel (toluene/ethyl acetate = 10/1 by volume).

Yield: 0.48 g (67% of theory), Melting point: 110-112°C Calculated: C 72.47 H 8.39 N 5.83 Found: 72.61 8.54 5.97 Enantiomeric purity: ee = 98.5% (S) [HPLC method: see Example 1].

Example 6 Ethyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate Prepared from (S)-2-hydroxy-4-[N-(1-(2-piperidino-phenyl) -3-methyl-l-butyl)-aminocarbonylmethyl]-benzoic acid analogously to Example 5 using 2 equivalents of sodium hydride and 2 equivalents of ethyl iodide. Yield: 42% of theory, Melting point: 110-112°C Calculated: C 72.47 H 8.39 N 5.83 Found: 72.61 8.54 5.99 Enantiomeric purity: ee = 98.3% (S) [HPLC method: see Example 1]. 912519 Example 7 Ethyl (S)( + )-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate and Ethyl (R)(-)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate 920 mg of ethyl (±)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl) -3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate are separated, in single doses of 10 mg, on a preparative chiral phase HPLC column made by Baker, in which (S)-N-3,5-dinitrobenzoyl-leucine is covalently bonded to aminopropyl-silica gel (particle size: 40 /xm; column length: 250 mm with an internal diameter of mm; eluant: n-hexane/tetrahydrofuran/ethanol/ methylene chloride (180/20/3/2 by volume); flow rate: 21.25 ml per minute; temperature: 27°C; UV-detection at 285 nm), in which first the (R)(-)-enantiomer (peak 1) and then the (S)(+)-enantiomer (peak 2) is eluted.

After evaporation in vacuo, the following are obtained from the correspondingly cut and collected fractions: Peak 1 fraction (R): 423 mg (crude), Peak 2 fraction (S): 325 mg (crude).

In order to remove any impurities (including the stabiliser 2,6-di-tert.butyl-4-methyl-phenol contained in the tetrahydrofuran) the two fractions are each purified by column chromatography on silica gel (toluene/acetone = 10/1).

(R)(-)-enantiomer: Yield: 234.5 mg (51% of theory), Melting point: 122-124"C (petroleum ether + acetone) Calculated: C 72.47 H 8.39 N 5.83 Found: 72.40 8.18 5.71 [a]p°= - 8.3° (c = 1 in methanol) (S)-enantiomer: Yield: 131.2 mg (28.5% of theory), 912519 Melting point: 122-124°C (petroleum ether/acetone = 8/1) Calculated: C 72.47 H 8.39 N 5.83 Found: 72.28 8.44 5.70 [a]p°= + 8.3° (c = 1 in methanol) A chiral cell OD column made by Daicel is also suitable for separating the enantiomers. The (R)-enantiomer is eluted after 6.8 minutes and the (S)-enantiomer after 8.5 minutes on a column 250 mm long with an internal diameter of 4.6 mm (eluant: absolute ethanol/(n-hexane + 0.2% diethylamine = 5/95 by volume); temperature: 40°C; UV-detection at 245 nm).

Example 8 (R)(-)-2-Ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl) -aminocarbonylmethyl ] -benzoic acid x 0.4 H20 Prepared from 150 mg (0.312 mMol) of ethyl (R)(-)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonyl-methyl]-benzoate [melting point: 122-124 ° C; [a]20= - 8.3° (c = 1 in methanol)] by saponification with IN sodium hydroxide solution in ethanol analogously to Example 3.

Yield: 95.8 mg (66.7% of theory), Melting point: 103-105°C (toluene/petroleum ether) Calc. (X 0.4 H20) : C 70.51 H 8.01 N 6.09 Found: 70.88 7.79 5.81 Molecular peak M+: Calculated: 452 Found: 4 52 [a]p°= - 6.5° (c = 1 in methanol) Enantiomeric purity: ee = 99.7% (R) [HPLC method: see Example 3]. 912519 Example 9 (S)(+)-2-Ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl ) -aminocarbony lmethyl ] -benzoic acid x 0.4-H20 Prepared from 89 mg (0.198 mMol) of ethyl (S)(+)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl]-benzoate [melting point: 122-124°C; [a]p°= + 8.3° (c = 1 in methanol)] by saponification with IN sodium hydroxide solution in ethanol analogously to Example 3.

Yield: 44.5 mg (48.8% of theory), Melting point: 102-103°C (toluene/petroleum ether) Calc.: (x 0.4 H20) C 70.51 H 8.01 Found: 7 0.80 8.06 [a]p°= + 6.7° (c = 1 in methanol) Enantiomeric purity: ee = 99.6% (S) [HPLC method: see Example 3].

Example 10 (S)-2-Ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl) -aminocarbonylmethyl]-benzoic acid 0.26 g (0.47 mMol) of benzyl (S)-2-ethoxy-4-[N-(1-(2-pipieridino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl ] -benzoate (melting point: 91-92°C; [a]p°= + 9.5°; c = 1.05 in methanol) are hydrogenated in 10 ml of ethanol using 0.12 g of (10%) palladium/charcoal at 50°C and 5 bar of hydrogen. After hours the catalyst is filtered off over kieselguhr and evaporated down in vacuo. The evaporation residue is crystallised from ethanol/water (2/1 by volume).

Yield: 0.15 g (70% of theory), Melting point: 130-131°C Calculated: C 71.64 H 8.02 N 6.19 912519 Found: 71.76 8.12 6.05 Enantiomeric purity: ee = 99.6% [HPLC method: see Example 3].

Example 11 (S)-2-Ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl) -aminocarbonylmethyl]-benzoic acid 102 mg (0.20 mMol) of tert.butyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl ] -benzoate (melting point: 122-123°C; [a]p° = + 8.7°; c = 1 in methanol) are refluxed in 5 ml of benzene together with a few crystals of p-toluenesulphonic acid hydrate, for half a day. The desired product is then obtained, according to thin layer chromatography, according to the Rf value and mass spectrum.

Melting point: 129-131°C Molecular peak M+: Calc.: 452 Found: 452 Example 12 (S)-2-Ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl )-aminocarbonylmethyl]-benzoic acid 200 mg (0.395 mMol) of tert.butyl (S)-2-ethoxy-4-[N-(1-(2-piperidino-phenyl)-3-methyl-l-butyl)-aminocarbonylmethyl ] -benzoate (melting point: 122-123°C; [a]p°= + 8.7°; c = 1 in methanol) are stirred into 2 ml of methylene chloride together with 0.45 g (3.95 mMol) of trifluoroacetic acid overnight at ambient temperature. The mixture is evaporated down in vacuo and the evaporation residue is distributed between aqueous sodium hydrogen carbonate solution and ethyl 912519 acetate. The organic extract is dried, filtered and evaporated down in vacuo. The evaporation residue is crystallised from ethanol/water (2/1).

Yield: 115 mg (64.7% of theory), Melting point: 126-128°C Calculated: C 71.64 H 8.02 N 6.19 Found: 71.39 7.91 6.06 [a]p°= + 6.97° (c = 0.975 in methanol) Enantiomeric purity: ee = 99.8% [HPLC method: see Example 3].

Example 13 Tablets containing 0.25 mg of AG-EE 623 ZW Each tablet comprises: (1) 0.250 mg of active substance (2) 0.12 5 mg of N-methylglucamine (3) 0.038 mg of polyvinylpyrrolidone (4) 0.07 5 mg of polyoxyethylenepolyoxypropylene polymer (5) 0.150 mg of microcrystalline cellulose (6) 24.862 mg of sodium carboxymethyl starch (7) 24.000 mg of microcrystalline cellulose (8) 0.500 mg of magnesium stearate 50.000 mg Total weight The active substance and excipients (2) to (4) are dissolved in water at 90°C and the microcrystalline cellulose (5) is suspended therein. The dispersion is evaporated down in vacuo and the dry mass is screened to a mesh size of 1 mm. Ingredients (6) to (8) are then added to the dried granules.

Round, biplanar tablets weighing 50 mg and measuring 5 mm in diameter are compressed from this mixture. 912519 Example 14 Tablets containing 0.5 mg of AG-EE 623 ZW Each tablet comprises: (1) 0.500 mg of active substance (2) 0.250 mg of N-methylglucamine (3) 0.075 mg of polyvinylpyrrolidone (4) 0.150 mg of polyoxyethylenepolyoxypropylene polymer (5) 0.300 mg of microcrystalline cellulose (6) 24.225 mg of sodium carboxymethyl starch (7) 24.000 mg of microcrystalline cellulose (8) 0.50 0 mg of magnesium stearate 50.000 mg Total weight Round, biplanar tablets weighing 50 mg and measuring 5 mm in diameter are produced analogously to those of Example 13.

Example 15 Tablets containing 1.0 mg of AG-EE 623 ZW Each tablet comprises: (1) 1.00 mg of active substance (2) 0.50 mg of N-methylglucamine (3) 0.15 mg of polyvinylpyrrolidone (4) 0.03 mg of polyoxyethylenepolyoxypropylene polymer (5) 0.60 mg of microcrystalline cellulose (6) 23.22 mg of sodium carboxymethyl starch (7) 24.00 mg of microcrystalline cellulose (8) 0.50 mg of magnesium stearate 50.00 mg Total weight Round, biplanar tablets weighing 50 mg and measuring 5 mm in diameter are produced analogously to those of 912519 Example 13.

Example 16 Tablets containing 1.5 mg of AG-EE 623 ZW Each tablet comprises: (1) 1.500 mg of active substance (2) 0.750 mg of N-methylglucamine (3) 0.225 mg of polyvinylpyrrolidone (4) 0.04 5 mg of polyoxyethylenepolyoxypropylene polymer (5) 0.900 mg of microcrystalline cellulose (6) 23.080 mg of sodium carboxymethyl starch (7) 23.000 mg of microcrystalline cellulose (8) 0.500 mg of magnesium stearate 50.000 mg Total weight Round, biplanar tablets weighing 50 mg and measuring 5 mm in diameter are produced analogously to those of Example 13.

Example 17 Tablets containing 2.0 mg of AG-EE 623 ZW Each tablet comprises: (1) 2.00 mg of active substance (2) 1.00 mg of L-lysine (3) 1.00 mg of polyvinylpyrrolidone (4) 1.00 mg of polyoxyethylenepolyoxypropylene polymer (5) 4.00 mg of microcrystalline cellulose (6) 20.35 mg of microcrystalline cellulose (7) 20.00 mg of sodium carboxymethyl starch (8) 0.65 mg of magnesium stearate 50.00 mg Total weight 912519 The ingredients (1) to (4) are dissolved in water at 90°C and the microcrystalline cellulose (5) is suspended therein. The dispersion is processed in a spray dryer and ingredients (6) to (8) are then added.

Round, biconvex tablets weighing 50 mg and measuring 5 mm in diameter are compressed from this mixture and are given a flavour-masking coating of hydroxypropyl-methylcellulose.

Example 18 Tablets containing 2.5 mg of AG-EE 623 ZW Each tablet comprises: (1) 2.50 mg of active substance (2) 1.25 mg of L-lysine (3) 1.25 mg of polyvinylpyrrolidone (4) 1.2 5 mg of polyoxyethylenepolyoxypropylene polymer (5) 4.10 mg of microcrystalline cellulose (6) 19.50 mg of microcrystalline cellulose (7) 19.50 mg of sodium carboxymethyl starch (8) 0.65 mg of magnesium stearate 50.00 mg Total weight Round, biconvex tablets weighing 50 mg and measuring 5 mm in diameter are produced analogously to those in Example 17 and given a flavour-masking coating of hydroxypropylmethyl cellulose.

Example 19 Tablets containing 3.0 mg of AG-EE 623 ZW Each tablet comprises: (1) 3.0 mg of active substance 912519 (2) 1.5 mg of L-lysine (3) 1.5 mg of polyvinylpyrrolidone (4) 1.5 mg of polyoxyethylenepolyoxypropylene polymer (5) 21.5 mg of microcrystalline cellulose (6) 21.0 mg of sodium carboxymethyl starch 50.0 mg Total weight The ingredients (1) to (4) are dissolved in water at 90°C and the solution is processed in a spray dryer. Then, ingredients (5) and (6) are added.

Round, biconvex tablets weighing 50 mg and measuring 5 mm in diameter are compressed from this mixture and given a flavour-masking coating of hydroxypropylmethyl cellulose.

Example 20 Tablets containing 5 mg of AG-EE 623 ZW Each tablet comprises: (1) 5.0 mg of active substance (2) 2.5 mg of L-lysine (3) 2.5 mg of polyvinylpyrrolidone (4) 2.5 mg of polyoxyethylenepolyoxypropylene polymer (5) 19.0 mg of microcrystalline cellulose (6) 18.5 mg of sodium carboxymethyl starch 50.0 mg Total weight Round, biconvex tablets weighing 50 mg and measuring 5 mm in diameter are produced analogously to those in Example 19 and given a flavour-masking coating of hydroxypropylmethyl cellulose.

IE 912519

Claims (14)

Claims:

1. (S)(+)-2-Ethoxy-4-[N-[1-(2-piperidino-phenyl)-3-methyl-l-butyl]aminocarbonylmethyl]-benzoic acid-in at least substantially optically pure form or an addition salt thereof.

2. A compound as claimed in claim 1 which is substantially optically pure.

3. A compound as claimed in claim 2 having an optical purity of at least ee = 95%.

4. A compound as claimed in claim 2 having an optical purity of at least ee = 98%.

5. A compound as claimed in any one of claims 1 to 4 being a physiologically acceptable addition salt.

6. A process for the preparation of a compound as claimed in claim 1, said process comprising at least one of the following steps: a) reacting the (S)-amine of formula I IE 912519 - 45 - CH3 CHj ch / h n h N with a carboxylic acid of formula II hoocch och2ch3 (I (wherein W represents an optionally protected carboxy group) or with a reactive derivative thereof, optionally prepared in the reaction mixture, and subsequently, necessary, cleaving any protecting group used; b) cleaving an (S)-compound of formula III IE 912519 - 46 - CH j CH CH N H I 1 0 C 2 H 5 (III) (wherein A represents a group which may be converted into a carboxy group by hydrolysis, thermolysis or hydrogenolysis); (IV) (wherein W' represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group) with a compound of formula V Z - CH2 - CH3 (V) (wherein Z represents a nucleophilic leaving group or, together with the adjacent hydrogen atom represents a diazo group) and subsequently, if necessary, hydrolysing or IE 912519 - 47 - hydrogenolysing a compound thus obtained; d) enantioselectively reducing a compound of formula VI (wherein W represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group, and Y represents a group of formula and subsequently, if necessary, hydrolysing a compound thus obtained; e) oxidising an (S)-compound of general formula VII 0 C H 2 C H j •W ' (VI) (wherein W" represents (VII) a group which can be converted into a IE 912519 - 48 - carboxy group by oxidation); f) separating a mixture comprising an amount of the (S)-enantiomer of formula VIII c H 3 C H , \ / CH V ■ NH W • (VIII) and an amount of the (R)-enantiomer of formula IX 0 C H 2 C H i (IX) (wherein W1 represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group); g) converting an (S)-enantiomer obtained in any one of steps (a) to (f), having an optical purity of at least 90%, into an (S)-enantiomer having an optical purity of at least 95% by fractional crystallisation; and h) converting an (S)-enantiomer thus obtained into an addition salt thereof or an addition salt of the (S)- IE 912519 - 49 - enantiomer into the free (S)-enantiomer.

7. A pharmaceutical composition comprising an (S)-enantiomer as claimed in any one of claims 1 to 4 at least substantially free from other isomers thereof, or a physiologically acceptable addition salt thereof together with at least one pharmaceutical carrier or excipient.

8. Use of a compound as claimed in any one of claims 1 to 4 or a physiologically acceptable addition salt thereof for the manufacture of a therapeutic agent for the treatment of diabetes mellitus.

9. A method of treatment of the human or non-human animal body to combat diabetes mellitus, said method comprising administering to said body an (S)-enantiomer as claimed in any one of claims 1 to 4 at least substantially free from other isomers thereof, or a physiologically acceptable addition salt thereof.

10. Compounds of formulae I, III, IV and VII IE 912519 - 50 - (I) [(S)-3-Methyl-l-(2-piperidino-phenyl)-l-butylamine] CH3 CH, CH IX ■NH oc2h5 (III) (IV) IE 912519 51 CH CH \ / CH 0 •W" OCHjCHj (VII) (wherein A represents a group which can be converted into a carboxy group by hydrolysis, thermolysis or hydrogenolysis; W' represents a carboxy group or an alkoxycarbonyl group having a total of 2 to 5 carbon atoms and in which the alkoxy group may additionally be substituted by a phenyl group; and W" represents a group which may be converted by oxidation into a carboxy group) and the addition salts thereof.

11. A compound as claimed in any one of claims 1 to 4 or a pharmaceutical composition thereof substantially as herein disclosed in any one of the Examples.

12. Each and every novel compound, composition, process, use and method as herein disclosed.

13. A process for the preparation of a compound as claimed in claim 1 substantially as described herein with reference to the Examples and/or the accompanying drawings.

14. A compound as claimed in claim 1 whenever prepared by a process as claimed in claim 6 or 15. Dated this the 18th day of July, 1991. BY: TOMKINS & CO. (Signed)