GB2084577A - Secondary Amines - Google Patents

Abstract

A compound of formula (I): <IMAGE> wherein R<1> and R<2> are hydrogen or methyl, R<3> is hydroxy, hydroxyalkoxy, benzyloxy or X-Y-Z wherein (i) X is a bond or oxygen, Y is C1-6 straight or branched alkylene, and Z is hydrogen or carboxy; or (ii) X is a bond or moiety -O-CH2-, Y is C2-6 straight or branched alkenylene, and Z is carboxy; and R<4> is an optional substituent, and n is 1, 2, or 3, their esters, amides and salts, are anti-obesity, hypoglycaemic, anti-inflammatory and platelet aggregation inhibiting agents.

Description

SPECIFICATION Secondary Amines The present invention relates to derivatives of 2-(2-benzofuranyl)ethanolamine which have antiobesity, hypoglycaemic, anti-inflammatory and platelet-aggregation inhibiting activity, to processes for their production and to their use in medicine.

It has now been found that a series of 2-(2-benzofuranyl)ethanolamine derivatives have good hypoglycaemic, anti-inflammatory and platelet-aggregation inhibiting properties, increasing energy expenditure whilst having little cardiac stimulant activity.

Accordingly, the present invention provides a compound of formula (I)

or an ester, amide or salt thereof, where appropriate, wherein R' is hydrogen or methyl; R2 is hydrogen or methyl; R3 is hydroxy, hydroxy (C1~6) alkoxy, benzyloxy or a group X-Y-Z wherein: (i) X is a bond or oxygen, Y is Cie straight or branched alkylene, and Z is hydrogen or carboxy; or (ii) X is a bond or moiety -0-CH2-, Y is C26 straight or branched alkenylene and Z is carboxy.

R4 is selected from hydrogen, hydroxy, halogen, C16 alkyl and C16 alkoxy; and n is 1, 2 or 3.

In the case where the compound of formula (I) is an ester or amide, R3 is suitably a group X-Y COR5 in which R5 is C16 alkoxy or NR6R7 and P6 and R7 are the same or different and each is selected from hydrogen and C16 alkyl.

The C16 alkyl and C16 alkoxy groups mentioned above may each be straight or branched.

Suitably such alkyl and alkoxy groups have from 1 to 4 carbon atoms, particular examples being methyl, ethyl, methoxy and ethoxy groups.

Suitably Y is a C13 straight or branched alkylene, such as methylene or ethylene, or a C2 or C3 straight or branched alkenylene, such as ethenylene Preferably R1 and R2 are different, i.e. one is hydrogen and the other is methyl.

Most suitably R3 is methyl or a group X--YY-CORS wherein R5 is methoxy.

R4 may be in any position on the phenyl ring. Suitably it is in the meta position relative to the ethanolamine moiety. Most suitably R4 is a methyl or hydrogen substituent.

Preferably n is 1 or 2, most preferably 1.

Pharmaceutically acceptable salts of compounds of formula (I) include acid addition salts formed with a pharmaceutically acceptable acid such as hydrochloric acid, hydrobromic acid, orthophosphoric acid, sulphuric acid, methane sulphonic acid, toluenesulphonic acid, acetic acid, propionic acid, lactic acid, citric acid, fumaric acid, malic acid, succinic acid, salicylic acid or acetylsalicylic acid.

The salts and esters of compounds of formula (I) need not be pharmaceutically acceptable as they are also useful in the preparation of other compounds of formula (I) and in the separation of stereoisomers of compounds of formula (I) when the salt ion or ester radical is also optically active.

When R3 is a group X-Y-CO2H, the compounds of formula (I) may also be provided as pharmaceutically acceptable salts of the carboxylic acid. Such salts include alkali metal salts, alkaline earth metal salts and ammonium salts, preferably sodium, potassium, magnesium, calcium or ammonium salts.

Compounds of formula (I) have at least one asymmetric carbon atom, ie the one bearing the hydroxyl and benzofuranyl groups, and, when R' and R2 are different, the carbon atom bearing R1 and R2 is also asymmetric. The compounds may, therefore, exist in at least two and often four stereoisomeric forms. The present invention encompasses all stereisomers of the compounds of formula (I) whether free from other stereoisomers or admixed with other stereoisomers in any proportion and thus includes, for instance racemic mixtures of enantiomers.

Preferably, the carbon atom bearing the hydroxyl and benzofuranyl groups has the R configuration.

Preferably, the carbon atom bearing R' and R2, when these are different, has the R configuration.

The most potent compounds of formula (I) are those wherein R' and R2 are different and both asymmetric carbon atoms are in the R configuration.

The absolute configuration of any compound of formula (I) may be determined by conventional Xray crystallographic techniques.

It is believed that, in the '3C n.m.r. of compounds of formula (I) wherein one of R' and R2 is hydrogen and the other is methyl, the diastereoisomer having the greater anti-obesity activity is that for which the signal of the methyl group carbon atom appears at higher field (the lower numerical value when expressed in ppm) in d6DMSO solution. The paired resonances often appear at approximately 20 ppm (less active) and slightly below 20 ppm (more active) down field from tetramethylsilane. Other paired resonances can occur for the carbon atoms attached directly to the nitrogen atom and the carbon which carries the hydroxyl and benzofuranyl groups. Again the paired resonances of the more active diastereomer of the investigated compounds appear at the higher field position.

Certain compounds of formula (I) have an alkenyl moiety (in R3) and may, therefore, exist in both E and Z geometrical isomeric forms. The present invention encompasses both E and Z isomers of such compounds, whether in the isomerically pure state or admixed in any proportions.

Preferably, compounds of formula (I) having an alkenyl moiety in R3 are in the E configuration.

The present invention also provides a process for producing a compound of formula (I) by reducino a compound of formula (II)

wherein R', R4 and n are as defined in relation to formula (I); R8 is a group R3 as defined in relation to formula (I) or alkoxycarbonylalkoxy; R9 is a group R2 as defined in relation to formula (I) or together with R forms a bond; R'O is hydrogen, benzyl or together with R9 or P11 forms a bond; R1' is hydrogen or together with R12 forms an oxo-group or together with R'O forms a bond; R12 is hydrogen or together with R" forms an oxo-group;; R'3 is hydroxyl or together with R'4 forms an oxo-group; R'4 is hydrogen or together with R'3 forms an oxo-group, Provided that there is no more than one oxo-group and no more than one bond represented by any of R9 to P14, and optionally thereafter forming a salt, ester or amide of the compound of formula (I) so formed and/orconverting the compound of formula (I) so formed into a further compound of formula (I).

When there are two or more reducible moieties in the compound of formula (II) these may, generally, be reduced separately in any order or simultaneously. However, when R3 is an alkenylene group, or contains an alkenylene group, the double bond thereof may be reduced at the same time as any reducible moiety elsewhere in the molecule. When R8 is an alkoxycarbonylalkoxy group this may be reduced simultaneously with or separateiy to the reduction of other reducible moieties in the molecule.

The aforementioned reductions may be effected by conventional chemical or catalytic methods, such as chemical reduction using a complex hydride such as lithium aluminium hydride, sodium cyanoborohydride.or sodium borohydride or aluminium amalgam or by catalytic hydrogenation using catalysts such as palladium on charcoal, or platinum, for instance, as platinum oxide, except when R8 has an alkenylene group, as this will be reduced simultaneously.

Catalytic hydrogenation is conveniently effected using hydrogen gas at about 1 atmosphere pressure when platinum is used as catalyst and at medium to high pressure, conveniently 50 to 100 psi, when a palladium catalyst is used. Such hydrogenations may be conducted in conventional hydrogenation solvents such as a lower alkanol, for instance ethanol and at any convenient, nonextreme temperature. It is generally most suitable to use a slightly raised temperature such as 300C to 1 000C, for example 400C to 800 C.

The desired compound may be isolated from the reaction mixture by evaporation of the filtered solution. The initially obtained product may be purified by conventional means, for example by chromatography, crystallisation or the like.

Reduction by sodium borohydride is conveniently effected in a lower alkanolic solvent such as methanol. The reaction is generally carried out at a temperature of, for example, 20 to 300C.

Reduction by lithium aluminium hydride is conveniently effected in a dry, ether solvent such as diethyl ether or tetrahydrofuran at ambient or elevated temperature.

The desired compound may be obtained by hydrolysis of the reaction mixture, extraction into a suitable solvent such as ethyl acetate and evaporation. The initially obtained product may be purified as outline hereinbefore.

In particular aspects, the present invention provides processes for producing compounds of formula (I) by reducing a compound of formula (ill):

or reducing a compound of formula (lIB):

or reducing a compound of formula (IIC):

or the N-benzyl derivative thereof, or reducing a compound of formula (IID):

or reducing a compound of formula (IIE):

or reducing a compound of formula (IIF):

or reducing a compound of formula (lIG):

wherein R1, R2, R4, R5, R8, n, X and Z are as defined in relation to formulae (I) and (II); Y' is C18 straight or branched alkylene; and Y" is C28 straight or branched alkenylene.

The present invention also provides a process for producing a compound of formula (I) by reacting a compound of formula (Ill):

with a compound of formula (IV):

or a salt, ester or amide thereof wherein R', R2, R3, R4 and n are as defined in relation to formula (I); and optionally thereafter forming a salt, ester or amide of the compound of formula (I) so formed and/or converting the compound of formula (I) so formed into a further compound of formula (I).

This reaction is conveniently effected in a solvent such as a lower alkanol, preferably ethanol.

Esters, amides and salts of compounds of formula (I) may be produced directly using the appropriate compound of formula (II) or may be produced from the free acid of formula (I) by conventional means. Free acids of formula (I) may be obtained directly or by cleavage of the corresponding ester or amide, or from the corresponding salt by conventional means.

The compounds of formula (I) so produced may be purified by conventional means such as crystallisation and/or chromatography.

Those compounds of formula (I) having only one asymmetric carbon atom (i.e. when R' and R2 are the same) may, if desired, be resolved into enantiomers by conventional means, for example by the use of an optically active acid as a resolving agent. Those compounds of formula (I) having two asymmetric carbon atoms may be separated into diastereomeric pairs of enantiomers by, for example, fractional crystallisation from a suitable solvent such as ethyl acetate or benzene. The pair of enantiomers thus obtained may be separated into individual stereoisomers by conventional means such as by the use of an optical active acid as a resolving agent.

Suitable optically active acids which may be used as resolving agents are described in "Topics in Stereochemistry" Vol 6, Wiley Interscience, 1971; Allinger N Land Eliel, W. L. (Eds).

Any desired enantiomer of a compound of formula (I) may be obtained by stereospecific synthesis using optically pure starting materials of known configuration. Thus, by using single enantiomers of the compounds of formula (Ill) and (IV) a required enantiomer of the corresponding compound of formula (I) can be obtained. Similarly, the reaction of a single enantiomer of a compound of formula (V) with a single enantiomer of formuia (VIC) below will result in a single enantiomerofa compound of formula (IID) above. The latter may be reduced to a compound of formula (I) without altering the stereochemical configuration thereby affording a single enantiomer of the compound of formula (I).

Reaction of a compound of formula (V) with a single enantiomer of a compound of formula (VID) will give a single enantiomerof a compound of formula (i) directly. Thus, for instance, the R enantiomerofa compound of formula (VID) or (VIC), when reacted with the R enantiomer of a compound of formula (V) directly or indirectly affords the RR enantiomer of the desired compound of formula (I).

Many of the reductions described in relation to compounds of formula (II) directly involve the asymmetric, or potentially asymmetric carbon atoms and consequently result in the formation of mixtures of stereoisomers. Thus reduction of a single enantiomer of a compound of formula (ill), (lIB) or (IIC) will result in the formation of a pair of enantiomers of a corresponding compound of formula (I) whereas reduction of a racemic mixture of enantiomers of a compound of formula (IIA) (IIB) or (IIC) will result in the formation of a mixture of all four enantiomers of the corresponding compound of formula (I).Such mixtures may be separated into pairs of enantiomers and/or resolved into single enantiomers as described above.

Compounds of formula (il) may be produced by reacting a compound of formula (V):

or a salt, ester or amide thereof wherein R', R2, R4, R3 and n are as defined in relation to formulae (I) and (II) and R15 is hydrogen or benzyl with a compound of formula (VI):

wherein W is a reactive moiety which is capable of reacting with the amine of formula (V) thus forming a compound of formula (II). Typical examples of compounds of formula (VI) are:

or its hydrate or hemiacetal of a lower alkanol;

wherein V is a halogen atom, preferably bromine;

wherein O-L is a leaving group, preferably tosyloxy.

and

It will be appreciated that when R8 is a group R3 and R'5 is hydrogen, the reaction of a compound of formula (V) with the compound of formula (VID) or (III) produces a compound of formula (I) directly, the latter being identical to the reaction between compounds of formulae (Ill) and (IV) above.

Conventional conditions suitable for use with the particular compound of formula (Vl) may be used for this reaction. Thus the reaction of a compound of formula (VIA) with a compound of formula (V) is conveniently conducted at elevated temperature under conditions resulting in the removal of the water formed during the reaction. A particularly suitable method is to perform the reaction in a solvent such as benzene, under reflux and azeotropically to remove the water using a Dean and Stark trap.

The reaction of a compound of formula (VIB) with a compound of formula (V) is conveniently conducted in a polar organic solvent such as acetonitrile or butanone, at an elevated temperature, for instance under reflux.

The reaction of a compound of formula (VIC) with a compound of formula (V) is conveniently conducted under standard peptide formation reaction conditions.

The reaction of a compound of formula (VID) with a compound of formula (V) is conveniently conducted in a solvent such as dimethyl sulphoxide at elevated temperature, preferably 500C for about 3 days.

The reaction of a compound of formula (ill) with a compound of formula (V) is conveniently conducted in a solvent such as a lower alkanol, preferably ethanol.

Certain compounds of formula (II) may also be produced by reacting a compound of formula (VII):

with a compound of formula (VIII):

or a salt, ester or amide thereof wherein R', R3, R4 and n are as defined in relation to formula (i) R16 is a group R2 or together with R'7 forms a bond and R'7 is a group L such that O-L is a leaving group, preferably tosyloxy, or together with R15 forms a bond.

The reaction of a compound of formula (VII) with a ketone of formula (VIII) is conveniently effected under conditions which result in the removal of water formed during reaction. A particularly suitable method is to perform the reaction in a solvent, such as benzene, under reflux and azeotropically to remove the water using a Dean and Stark trap.

The reaction of a compound of formula (VII) with a compound of formula (VIII) wherein R17 is a group L is conveniently effected in a solvent such as dimethylsulphoxide at elevated temperature, preferably at about 500C for about two to three days.

It is often convenient to prepare the compound of formula (II) and then use it in situ without isolation to produce the required compound of formula (I).

The intermediates of formulae (III), (IV), (V), (VI) and (VII) may be produced by conventional methods.

In another aspect of the present invention there are provided the compounds of formula (II), (Ill), (Vl) or (VII) as hereinbefore defined. Such compounds are useful as intermediates in the production of compounds of formula (I).

A compound of formula (I), or pharmaceutically acceptable salt, ester or amide thereof, where appropriate, (hereinafter "the drug") may be administered as the pure drug, however, it is preferred that the drum be administered as a pharmaceutical composition also comprising a pharmaceutically acceptable carrier.

Accordingly, the present invention also provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt, ester or amide thereof, where appropriate, in association with a pharmaceutically acceptable carrier therefor.

As used herein the terms "pharmaceutical compositions" and "pharmaceutically acceptable" embrace compositions and ingredients for both human and/or veterinary use.

Usually the compositions of the present invention will be adapted for oral administration although compositions for administration by other routes, such as by injection are also envisaged. For use as anti-inflammatory agent compounds of the present invention are, preferably, formulated as topical compositions.

Particularly suitable compositions for oral administration are unit dosage forms such as tablets and capsules. Other fixed unit dosage forms, such as powders presented in sachets, may also be used.

In accordance with conventional pharmaceutical practice the carrier may comprise a diluent, binder, filler, disintegrant, wetting agent, lubricant, colourant, flavourant or the like.

Typical carriers may, therefore, comprise such agents as microcrystalline cellulose, starch, sodium starch glycollate, polyvinylpyrrolidone, polyvinylpolypyrrolidone, magnesium stearate, sodium lauryl sulphate, sucrose and the like.

Most suitably the composition will be provided in unit dose form. Such unit doses will normally comprise 0.1 to 500 mg, more usually 0.1 to 250 mg and favourably 0.1 to 100 mg. Such doses may be taken one to six times a day in a manner such that the total daily dose for a 70 kg adult will generally be about 0.1 to 1000 mg and more usually about 1 to 500 mg.

In addition to use in human medicine the compositions of this invention may be used to treat obesity, hyperglycaemia, inflammation and to inhibit platelet aggregation in domestic mammals such as dogs. In general, administration to domestic mammals may be by mouth and will usually take place one or two times a day at about 0.025 mg/kg to 2.5 mg/kg, for example 0.1 mg/kg to 2 mg/kg.

The present invention further provides a method for treating obesity in humans or domestic mammals comprising administering an effective, non-toxic amount of a compound of formula (I) or a pharmaceutically acceptable salt, ester or amide thereof, where appropriate, or of a composition thereof as hereinbefore defined to an obese human or domestic mammal.

The present invention also provides a method for treating hyperglycaemia in humans or domestic mammals comprising administering an effective. non-toxic amount of a compound of formula (I) or a pharmaceutically acceptable salt, ester or amide thereof, where appropriate, or of a composition thereof as hereinbefore defined, to a hyperglycaemic human or domestic mammal.

The present invention further provides a method for treating inflammation in humans and domestic mammals comprising administering an effective, non-toxic amount of a compound of formula (I) or a pharmaceutically acceptable salt, ester or amide thereof, where appropriate, or of a composition thereof as hereinbefore defined, to a human or domestic mammal suffering from inflammation.

The present invention also provides a method for inhibiting platelet aggregation in humans and domestic mammals in need of such treatment, comprising administering an effective, non-toxic amount of a compound of formula (I) or a pharmaceutically acceptable salt, ester or amide thereof, or of a composition thereof as hereinbefore defined.

The invention will now be illustrated by reference to the following Examples, which are not intended to limit the invention in any way. The preparation of intermediates is described in the Description.

Example 1 N-[2-(4-Methylphenyl)-1 -methylethyl]- 2-(2-benzofuranyl)-2-hydroxy Ethanamine A mixture of 2-(2-benzofuranyi)-2-hydroxy ethanamine (1.0 g) and 4-methylphenylacetone (0.76 g) in benzene (50 ml) was heated under reflux using a Dean and Stark head until the required amount of water had been collected. The solvent was evaporated, replaced with ethanol (50 ml) and the solution hydrogenated at atmospheric pressure over platinum oxide until the theoretical amount of hydrogen had been taken up. The reaction mixture was filtered through diatomaceous earth, the filtrate evaporated and the residue chromatographed on Kieselgel 60.Elution with 2% methanol-chloroform gave N-[2-(4-methylphenyl)-1 -methylethyl]-2-(2-benzof ura nyl)-2-hydroxy ethanamine, as an 80:20 mixture of diastereoisomers, m.p. 9298 (cyclohexane).

1H nmrT(CDCI3): 9.05 (3H, d, J=6Hz), 7.75 (3H, s), 6.9-7.4 (5H, m), 6.5-7.0 (2H, broad), 5.27 ( 1 H, t, J=6Hz), 3.3 (1 H, s), 3.0 (4H, s) 2.9-2.7 (2H, m) 2.4-2.6 (2H, m).

Example 2 N-[2-(4- [( E)-2-Carbomethoxyethenyl] phenyl )-1 -methylethyl]-2-(2-benzofuranyl )-2- hydroxyethanamine A mixture of 2-(2-benzofuranyl)-2-hydroxyethanamine (1.0 g) and 4-[(E)-2carbomethoxyethenyl]phenyl propan-2-one (1.13 g) was heated under reflux using a Dean and Stark head until the theoretical amount of water had been removed. The solvent was evaporated, the residue dissolved in methanol (50 ml) and sodium borohydride (0.5 g) added. The solvent was evaporated, the residue partitioned between water and ethyl acetate and the organic layer dried (magnesium sulphate).

Removal of the solvent gave an oil which was chromatographed on Kieselgel 60. Elution with 2% methanol-chloroform gave N-[2-(4-[(E)-2-carbomethoxyethenyl] phenyl)- 1 -methylethyl]-2-(2benzofuranyl)-2-hydroxyethanamine, as a 54:46 mixture of diastereoisomers, m.p. 85-89 (cyclohexane).

1H nmr T(CDCí3): 9.05 (3H, d, J=6Hz), 7.0-7.5 (5H, m), 6.75 (1 H, s replaceable with Do0),6.3 (3H, s), 5.3 (1 H, m), 4.5 (1 H, broad, replaceable with D2O), 3.5 (1 H, d, J=1 5Hz), 3.33 (1 H, s), 2.8 (4H, m), 2.5 (4H, m), 2.4 (1 H, d, J=1 5Hz).

Example 3 N-[2-(4-Carbomethoxymethoxyphenyl)-1 -methylethyl]-2(2-benzofuranyl)-2-hydroxyethanamine By a method exactly analogous to that described in Example 2 but using 2-(2-benzofuranyl)-2- hydroxyethanamine (1.3 g) and 4-carbomethoxymethoxyphenylpropan-2-one (1.63 g), N-t2-(4- carbomethoxymethoxyphenyl)- 1 -methylethyl]-2-(2-benzofura nyl)-2-hydroxyethana mine was prepared (0.25 g) as 55:45 mixture of diastereoisomers, m.p. 79-87 (hexane).

1 H nmr T(CDCI3): 8.95 (3H, d, J=6Hz), 6.5-7.8 (7H, m, 2H replaceable by D2O),6.18 (3H, s), 5.42 (2H, m), 5.2 (1 H, m), 3.4 (1 H, s), 2.3-3.5 (8H, m).

Example 4 N-[2-(4-(3-Carbomethoxypropoxy)phenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2hydroxyethanamine By a method analogous to that described in Example 2 but using 2-(2-benzofuranyl)-2hydroxyethanamine (4.54 g) and 1 -(4-[3-carbomethoxypropoxy]phenyl)propan-2-one (6.41 g), N-[2 (4-(3-carbomethoxyphenoxy)phenyl)-1 -methylphenyl]2-(2-benzofuranyl)-2-hydroxyethanamine was prepared, m.p. 63-700C (eft20) as a 37:63 mixture of diastereoisomers.

1 H nmr T(CDCI3): 8.95 (3H, d), 6.8-8.2 (11 H, complex), 6.35 (3H, s), 6.1 (2H, t), 5.2 (1 H, m), 2.35-3.5 (9H, complex).

Example 5 Preparation of (RR,SS) and (RS,SR) (N-[2-(4-methylphenyl)-1-methylethyl]-2-(2-benzofuranyl)-2hydroxyethanamine A mixture of 2-benzofuran glyoxal (10.44 g) and 2-amino-3-'(4-methylphenyl)propane (8.94 g) was refluxed in benzene using a Dean and Stark head until the theoretical amount of water had been removed. The solvent was evaporated, replaced with methanol and sodium borohydride (5 g) added.

The methanol was evaporated, the residue partitioned between water and ether and the ether layer dried. Filtration and evaporation gave an oil which was chromatographed on Kieselgel 60. Elution with 2% methanol-chloroform gave N-[2-(4-methylphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2- hydroxyethanamine (14 g).

Recrystallisation of this material twice from benzene yielded the (RS,SR) diastereoisomer in 96% diastereomeric purity (2.4 g), m.p. 114-120. Evaporation of the original mother liquor and recrystallisation of the solid three times from hexane gave 1.3 g, m.p. 88--1000, of 72% (RR,SS) material. Recrystallisation of this from benzene gave the (RR,SS) diastereoisomer (0.52 g) m.p. 102- 1050 in 90% diastereomeric purity.

1 H nmr identical with that described in Example 1.

Example 6 N-[2-(4-Methylphenyl)ethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine By a method analogous to that described in Example 5 but using 2-(4-methylphenyl)ethylamine (3.39 g) and 2-benzofuranlyoxal (3.08 g), N-[2-(4-methylphenyl)ethyl]-2-(2-benzofuranyl)-2- hydroxyethanamine m.p. 112--1130 (ethyl acetate) was prepared.

1H nmrT(CDCI3): 7.7 (3H, s), 7.5 (2H, broad, disappears with D2O), 7.05-7.4 (4H, m), 6.95 (2H, d, J=6Hz), 5.2 (1 H, t, J=6Hz), 3.4 (1 H, s), 2.95 (4H, s), 2.4-2.9 (4H, m).

Example 7 N-[3-(4-Methylphenyl)-1 -methylpropyl]-2-(2-benzofuranyl)-2-hydroxyethana mine By a method analogous to that described in Example 2 but using 2-(2-benzofuranyl)-2hydroxyethanamine (2.03 g) and 4-(4-methylphenyl)butan-2-one (2.04 g), N-[3-(4-methylphenyl)-1 methylpropyl]-2-(2-benzofuranyl)-2-hydroxyethanamine, m.p. 83--840 (hexane) was prepared as a 1:1 mixture of diastereoisomers.

1 H nmr T(CDC3): 8.9 (3H, d, J=6Hz), 8.15-8.65 (2H, m), 7.7 (3H, 5), 7.1--7.6 (5H, m, includes 2H replaceable by D2O), 7.0 (2H, m), 5.2 (1 H, t, 4=6Hz) 3.35 (1 H, s), 2.9 (4H, s), 2.4-2.9 (4H, m).

Example 8 N-[3-(4-Methylphenyl)-1 1 -dimethylpropyl]-2(2-benzofuranyl)-2-hydroxyethanami ne By a method analogous to that described in Example 5 but using 2-benzofuranyl glyoxal (2.65 g) and 4-(4-methylphenyl)-2-amino-2-methylbutane (3.0 g), N-[3-(4-methylphenyl)-1 ,1 -dimethylpropyl]- 2-(2-benzofuranyl)-2-hydroxyethanamine, m.p. 121--1220 (ether) was prepared.

1H nmrT(CDCI3): 8.9 (6H, s), 8.3-8.6 (2H, m), 7.8 (3H, s) 7.3-7.65 (2H, m), 7.0-8.0 (2H, disappears with D2O), 7.0 (2H, d, J=6Hz), 5.3 (1 H, t, J=6Hz), 3.4 (1 H, s), 2.9 (4H, s), 2.4-2.9 (4H, m).

Example 9 N-[2-(4-Methylphenyl)-1 1 -dimethylethyl]-2-(2-benzofuranyl )-2-hydroxyethanamine By a method analogous to that described in Example 5 but using 2-benzofuranyl glyoxal (3.2 g) and 3-(4-methylphenyl)-2-amino-2-methylpropane (3.0 g), N-[2(4-methylphenyl)-1 , 1 -dimethylethyl]- 2-(2-benzofuranyl)-2-hydroxyethanamine, m.p. 95-1 000C (cyclohexane) was prepared.

1H nmrT(CDCI3): 8.9 (3H, s), 8.85 (3H, s), 7.3 (3H, s), 7.4 (2H, s), 6.7-7.5 (2H, broad), 6.95 (2H, d, J=5Hz), 5.25 (1 H, t, J=6Hz), 3.35 (1 H, s), 2.95 (4H, s), 2.4-2.85 (4H, m).

Example 10 N-[3-(4-Methylphenyl)propyl]-2-(2-benzofuranyl )-2-hydroxyethana mine A mixture of 2-(2-benzofuranyl)-2-hydroxyethanamine (1.75 g), 3-(4-methylphenyl)-1 -(4methylphenylsulphonyloxy) propane (3.0 g) and triethylamine (1.5 g) was stirred in dimethylsulphoxide for 2 days at ambient temperature. The mixture was poured into water, extracted with ether and the ether layers dried. Removal of the solvent gave an oil which was crystallised and recrystallised from ether to give N-[3-(4-methylphenyl)propyl]-2-(2-benzofuranyl)-2-hydroxyethanamine m.p. 11 8- 1190.

1H nmrT(CDCI3): 8.0-8.35 (2H, m), 7.7 (3H, s), 7.1-7.7 (6H, m, including 2H replaceable with D2O), 6.95 (2H, d, J=6Hz), 5.15 (1 H;t, J=6Hz), 3.35 (1 H, s), 2.95 (4H, s) 2.4-2.9 (4H, m).

Example 11 N-[2-(4-Hydroxyethoxyphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine A mixture of 1-(4-carbomethoxymethoxyphenyl)-propan-2-one (1 g) and 2-(2-benzofuranyl)-2hydroxyethanamine (0.8 g) in benzene (80 ml) was boiled under reflux for one hour, with azeotropic removal of water, using a Dean and Stark head. The solution was evaporated, the residue dissolved in methanol (80 ml), cooled in ice, and excess sodium borohydride added. The solution was stirred at ambient temperature for 1 hour, heated under reflux for one hour, the methanol evaporated and the residue partitioned between water and ethyl acetate. The dried organic extract was evaporated to give an oil which was chromatographed on silica gel in 4% methanol/dichloromethane.The resulting oil was treated with ethereal hydrogen chloride to give the title compound as the hydrochloride salt hemihydrate, isolated as a 50:50 mixture of diastereoisomers. (mpt 5665 ) (Ethyl Acetate-Ether).

1 H nmr T(CDCI3)Free Base 8.9 (3H, d, J=6Hz), 6.85-7.85 (7H, m, 2H replaceable by D2O), 6.0 (4H, s), 5.15 (1 H, m), 2.33-3.35 (9H, m).

Example 12 N-[2-(4-Carbomethoxymethoxy-3-methylphenyl )-1 -methylethyl]-2-(2-benzofuranyl )-2hydroxyethanamine By a method analogous to that described in Example 1 but using 2-(2-benzofuranyl)-2hydroxyethanamine (0.75 g) and 1-(4-carbomethoxymethoxy-3-methylphenyl)propan-2-one (1.0 g), N-[2-(4-carbomethoxymethoxy-3-methylphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2hydroxyethanamine was prepared, m.p. 11 5-30 (Et2O) as a 38:62 mixture of diastereoisomers.

1H nmrT(CDCI3): 8.9 (3H, d), 7.8 (3H, s), 6.8-7.7 (7H, m), 6.25 (3H, s) 5.4 (2H, s), 5.2 (1 H, m), 2.2-3.5 (8H, complex).

Example 13 N-[2-(4-Hydroxyphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine N-[2-(4-Benzoyloxyphenyl)-1 methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine (2 g) in ethyl acetate (150 ml) was hydrogenated over 5% palladium on charcoal at atmospheric pressure. After uptake of hydrogen had ceased the mixture was filtered and the filtrate evaporated to dryness.

Chromatography of the residual oil on Kieselgel 60 (5% methanol in dichloromethane) gave the title compound, m.p. 135--80. (EtOAc-ether), as a 94:6 mixture of diastereoisomers.

1 H nmr T(DMSO d6): 9.05 (3H, d), 6.8-7.9 (8H, complex), 5.25 (1 H, m), 2.3-3.5 (9H, complex).

Example 14 N-[2-(4-Benzyloxyphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine This was prepared in an identical manner to the compound described in Example 2 using 2-(2 benzofuranyl)-2-hydroxyethanamine (3.51 g) and 1 -(4-benzyloxyphenyl)propan-2-one (4.75 g).

Chromatography of the residual oily solid on Kieselgel 60 (4% methanol in dichloromethane) gave the title compound, m.p. 1 1 1--1220, as a 20:80 mixture of diastereoisomers.

1H nmr T(CDcl3): 8.95 (3H, d), 6.7-7.6 (7H, m), 4.9-5.35 (3H, s supedmposed on m), 2.3-3.5 (14H, complex).

Example 15 N-[2-(4-Methoxyphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-1 -hydroxyethanamine This compound was prepared in an identical manner to the compound described in Example 2 using 2-(2-benzofuranyl)-2-hydroxyethanamine (1.65 g) and 1 -(4-methoxyphenyl)propan-2-one (1.53 g). Chromatography of the residual oil on Kieselgel 60 (4% methanol in dichloromethane) gave the title compound. m.p. 75--850 (Et2O-hexane) as a 44:56 mixture of diastereoisomers.

1 H nmr T(CDCI3): 8.95 (3H, d), 6.8-7.6 (7H, complex), 6.25 (3H, s), 5.2 (1 H, m), 2.35--3.5 (9H, complex).

Description 1 2-(2-benzofuranyl)-2-hydroxyethanamine Trimethylsilylcyanide (1.63 g, 2 ml) was added to a solution of 2-formylbenzofuran (2.0 g), (prepared as described in French Patent No 1.537.206) and a trace of zinc iodide in dry ether (50 ml) at 0 under nitrogen. The reaction mixture was stirred under nitrogen at ambient temperature for 10 h.

This solution was then added dropwise to a suspension of lithium aluminium hydride (0.63 g) in dry ether under nitrogen. The mixture was heated under reflux for 1 h at the end of the addition. The reaction mixture was cooled; water (0.63 ml),2M sodium hydroxide (0.63 ml) and more water (1.89 ml) added, the reaction mixture filtered, the residue washed with chloroform and the combined solvents evaporated to give 2-(2-benzofuranyl)-2-hydroxyethanamine, (1.58 g).

1H nmr T(CDCI3): 7.9 (3H, broad, replaceable with D2O), 6.85 (2H, broad), 5.27 (1 H, t, J=5Hz), 3.4 (1 H, s), 2.9- 2.4 (4H, m).

Demonstration of Effectiveness of Compounds I) Anti-Obesity Activity The compounds were administered by oral gavage in water or carboxymethyl-cellulose suspension to genetically obese mice daily for 28 days. At the end of the time the carcass composition was determined. The results obtained were as follows: Compound of Dose g Lipid/Mouse Example No. mg/kg p.o. Treated Control *1 4.8 13.36 16.25 5mp102-5 4.8 16.16 21.10 10 8.6 23.13 19.72 *15 days only II) Effect on Energy Expenditure The effect of the compounds on the energy expenditure of mice was demonstrated by means of the following procedure: Female CFLP mice each weighing approximately 24 g were given food and water ad lib before and during the experiment. The compounds were dissolved in water by addition of one mole of hydrochloric acid per mole of compound and these solutions were administered orally to each of 1 2 mice. A further 12 mice were dosed orally with water. The mice were placed in boxes through which air was drawn and the oxygen content of the air leaving the boxes was measured. The energy expenditure of the mice was calculated for 21 hours after dosing from the volume of air leaving the boxes and its oxygen content following the principles described by J. B. de V. Weir, J. Physiol. (London 109, 1-9, (1949). The food intake of the mice was measured over this same period of 21 hours. The results are expressed as a percentage of the mean food intake or rate of energy expenditure of the mice dosed with water.

Mean Energy Compound of Dose Expenditure Mean Food Example No. (mg/kg po) lO/ol In take /O/o/ O-3h 0-21 h Control 100 100 100 1 17 175 134 107 2 21 152 115 107 3 21 174 120 88 4 22.9 135 105 70 Smpt 114--20 8.6 139 110 93 5mpt102-5 8.6 153 123 91 6 16.4 156 105 103 7 17.9 138 120 113 8 18.8 130 105 108 9 17.9 117 109 102 10 17.2 140 118 90 11 22.2 143 108 92 12 22.1 144 117 95 13 21.2 137 106 91 14 22.3 118 103 72 15 18.1 128 110 105 III) Cardiac Activity Rat hearts were perfused by the Langendorff procedure.

Hearts were dissected free within 30 seconds of death and reverse perfused via the aorta and coronary vessels with Krebs-Ringer bicarbonate solution (pH 7.4, CC) gassed with 95% oxygen: 5% carbon dioxide at a flow rate between 8-1 2 cm3/minute. Responses were observed after injection of drug dissolved in isotonic saline into the perfusion media. Heart rate and tension were displayed on a Ormed MX2P recorder via a tension transducer and heat ratemeter.

Results are expressed as a percentage of the maximum response due to salbutamol.

Compound of Dose added Heart Heart Example No. to Perfusate {,ug) Tension Rate Salbutamol 100 100 1 30 0 33 2 30 5 57 3 30 14 36 4 30 40 88 5mp114-20 30 0 0 5mp102-5 30 25 0 6 30 10 0 7 30 11 33 8 30 10 0 9 30 20 0 10 30 10 0 11 30 90 0 12 30 8 0 IV) Hypoglycaemic Activity Female CFLP mice, weighing approximately 25 9, were fasted for 24 hours prior to the study. The compounds under study were administered orally as an aqueous solution to each of 8 mice. 30 minutes later a blood sample (20 ism3) was obtained from the tail for the analysis of blood glucose.

Immediately after taking this blood sample, glucose (1 g/kg body weight) was administered subcutaneously to each mouse. 8 mice were given water as a control. Blood samples were then obtained from each mouse at 30.minute intervals for 120 minutes.

Compounds that produced a significant (P < 0.05) reduction on blood glucose, compared with control mice given water, at any time, interval, were considered active. The area under the blood glucose curve over the 2 hour period after the administration of the glucose was calculated for each compound and compared with the value for control animals.

Compound of Dose Reduction in Area Under Example No. (y mol/kg) Blood Glucose Curve ( /0) 2 2.6 11 3 2.6 56 4 1 18 11 1 41 12 1 28 13 12.5 45 14 12.5 35 15 2.5 27 V) Anti-lnflammatory Activity The method used is based on that described by G. Tonelli et al (Endocrinology, 77, 625-634, 1965). An inflammation is induced in the rat ear by the application of 50yl of a 1% solution of croton oil in tetrahydrofuran, test compounds being dissolved in the irritant vehicle. After 6 hours the inflammation is assessed by killing the animals and weighing the ears. Topical anti-inflammatory activity of a compound is generally considered to be shown when a significant (5% level) reduction in ear weight is seen compared to non-drug treated control.

Compound of Dose Example No. mg/rat ear Activity 5 mp 102-5 2.0 Active VI) Platelet Aggregation Inhibition Activity Male CFLP mice (ca 20 g, n=8) were dosed orally with compound or vehicle (controls) after an overnight fast. Two hours later each mouse received an intravenous dose of collagen (400 yg/kg, pH 6-6.6). Exactly 30 sec. after injection of collagen, each mouse was placed in a chamber of CO2 until respiration ceased. Blood platelet concentration was determined (Ultra-Flo 100 whole blood platelet counter, Clay Adams) in blood samples (3 ,ul) taken immediately from the inferior vena cava. Each concentration was expressed as a per cent of that obtained in a tail blood sample taken immediately before injection of collagen. Results are given in the table below.

Dose p.o. % Inhibition of re Compound ,umolrmg)/kg sponse to collagen, Aspirin 600(108) 29p < 0.05 Example 3 5(1.92) 29p=0.01

Claims (12)

Claims

1. A compound of formula (I):

or an ester, amide or salt thereof, where appropriate wherein R' is hydrogen or methyl; R2 is hydrogen or methyl; R3 is hydroxy, hydroxy (C,~6)alkoxy, benzyloxy or a group X-Y-Z wherein: (i) X is a bond or oxygen, Y is C18 straight or branched alkylene, and Z is hydrogen or carboxy; or (ii) X is a bond or moiety -O-CH2-, Y is C28 straight or branched alkenylene and Z is carboxy.

R4 is selected from hydrogen, hydroxy, halogen, C18 alkyl and C18 alkoxy; and n is 1,2, or 3.

2. A compound as claimed in claim 1 wherein one of R1 and R2 is hydrogen and the other is methyl.

3. A compound as claimed in claim 1 or claim 2 wherein R3 is methyl or a group X--Y--COR5 wherein R5 is methoxy.

4. N-[2-(4-n-.ethylphenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxy ethanamine N-[2-(4-[(E)-2-carbomethoxyethenyljphenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2hydroxyethanamine N-[2(4-carbomethoxymethoxyphenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine N-[2-(4-(3-Carbomethoxypropoxy)phenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2hydroxyethanamine (RR,SS) and (RS,SR) N-[2-(4-methylphenyl)-1 -methylethyl]-2-(2-benzofuranyl)-2hydroxyethanamine N-[2-(4-Methylphenyl)ethyl]-2-(2-benzof uranyl)-2-hydroxyethanamine N-[3-(4-Methylphenyl)-1 -methylpropyl]-2-(2-benzofuranyl)-2-hydroxyethanamine N-[3-(4-Methylphenyl)-1 , 1 -dimethylpropyl]-2-(2-benzofuranyl)-2- hydroxyethanamine N-[2-(4-Methylphenyl)-1 , 1 dimethylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine N-[3-(4-Methylphenyl)propyl]-2-(2-benzof ura nyl)-2-hydroxyethana mine N-[2-(4-Hydroxyethoxyphenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine N-[2-(4-Carbomethoxymethoxy-3-methylphenyl)- 1 -methylethyl]2-(2-benzofuranyl )-2- hydroxyethanamine N-[2-(4-Hydroxyphenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethana mine N-[2-(4-Benzyloxyphenyl)- 1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethana mine and N-[2-(4-Methoxyphenyl )- 1 -methylethyl]-2-(2-benzofuranyl)-2-hydroxyethanamine and salts thereof.

5. A process for producing a compound of formula (I) as defined in claim 1 which process comprises either (a) reducing a compound of formula (all):

wherein R1, R4 and n are as defined in relation to formula (I); R8 is a group R3 as defined in relation to formula (I) or alkoxycarbonylalkoxy; R9 is a group R2 as defined in relation to formula (I) or together with R'O forms a bond; R'O is hydrogen, benzyl or together with R9 or P11 forms a bond; R1' is hydrogen or together with R12 forms an oxo-group or together with R10 forms a bond;; R12 is hydrogen or together with R11 forms an oxo-group; R13 is hydroxyl or together with R14 forms an oxo-group; R14 is hydrogen or together with R13 forms an oxo-group, provided that there is no more than one oxo-group and no more than one bond represented by any of R9 to R14, or (b) reacting a compound of formula (III):

with a compound of formula (IV):

or a salt, ester or amide thereof wherein R1, R2, R3, R4 and n are as defined in relation to formula (I); and optionally thereafter forming a salt, ester or amide of the compound of formula (I) so formed and/or converting the compound of formula (I) so formed into a further compound of formula (I).

6. A compound useful in the production of a compound of formula (I) and characterised by formula (II) or(lll) as defined in claim 5 or formula (VI):

wherein W is a reactive moiety which is capable of reacting with a compound of formula (V):

wherein R1, R2, R4 and n are as defined in relation to formula (I) R8 is as defined in relation to formula (II) and R'5 is hydrogen or benzyl, thus forming a compound of formula (II), or formula (VII):

7. A pharmaceutical composition comprising a compound of formula (I) as defined in claim 1, or a pharmaceutically acceptable ester, amide or salt thereof, in association with a pharmaceutically acceptable carrier therefor.

8. A composition as claimed in claim 7 in unit dose form comprising from 0.1 to 500 mg of the compound of formula (I) or the ester, amide or salt thereof, per unit dose.

9. A process for producing a pharmaceutical composition as defined in claim 7 or claim 8, which process comprises admixing the compound of formula (I), or the ester, amide or salt thereof, with the carrier therefor.

10. A compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable ester, amide or salt thereof, for use in the treatment of the human or animal body.

11. A compound as claimed in claim 1 and substantially as hereinbefore described with reference to any one of Examples 1 to 5.

12. A process for producing a compound of formula (I) as claimed in claim 6 and substantially as hereinbefore described with reference to Examples 1 to 1 5.

1 3. A composition as claimed in claim 8 and substantially as hereinbefore described.