WO1991007378A1 - Cycloalkyl-substituted glutaramide diuretic agents - Google Patents

Abstract

Compounds of formula (I), wherein A completes a 4 to 7 membered carbocyclic ring which may be saturated or mono-unsaturated and which may optionally be fused to a further saturated or unsaturated 5 or 6 membered carbocyclic ring; B is (CH2)m wherein m is an integer of from 1 to 3; each of R and R4 is independently H, C¿1?-C6 alkyl, benzyl or an alternative biolabile ester-forming group; R?1¿ is H or C¿1?-C4 alkyl; R?2 is C¿1-C6 alkyl substituted by C1-C4 alkoxy, aryl or aryloxy and R5 is defined to include a range of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and substituted alkyl groups including in particular methoxyethyl, 2-methoxyethoxymethyl, N2-substituted-S-lysylaminomethyl, R-alanylaminomethyl and (2-amino-2-methyl-propanoyl) aminomethyl; are atriopeptidase inhibitors of utility in the treatment of hypertension, heart failure, renal insufficiency and other disorders.

Description

Cycloalkyl-substituted Glutaramide Diuretic Agents

This invention relates to a series of cycloal kyl-substituted glutaramide derivatives which are diuretic agents having utility in a variety of therapeutic areas inclnding the treatment of various cardiovascular disorders such as hypertension, heart failure and renal insufficiency.

According to the specification of our European patent applications EP-A-0274234 and EP-A-0343911 we describe and claim certain cycloalkyl-substituted gluterainide derivatives as diuretic agents. The present invention provides further related compounds having an extended substituent group in the

aminocycloalkanecarboxylate ring.

The compounds are inhibitors of the zinc-dependent, neutral endopeptidase E.C.3.4.24.11. This enzyme is involved in the breakdown of several peptide hormones, including atrial

natriuretic factor (ANF), which is secreted by the heart and which has potent vasodilatory, diuretic and natriuretic activity. Thus, the compounds of the invention, by iuihibiting the neutral endcpeptidase E.C.3.4.24.11, can potentiate the biological effects of ANF, and in particular the compounds are diuretic agents having utility in the treatment of a number of disorders, including hypertension, heart failure, angina, renal insufficiency, premenstrual syndrome, cyclical oedema, Menières disease, hyperaldosteronism (primary and secondary) pulmonary oedema, ascites, and hypercalciuria. In addition, because of their ability to potentiate the effects of ANF the compounds have utility in the treatment of glaucoma. As a further result of their ability to inhibit the neutral endopeptidase E.C.3.4.24.11 the compounds of the invention may have activity in other therapeutic areas including for example the treatment of asthma, inflammation, pain, epilepsy, affective disorders, dementia and geriatric confusion, obesity and gastrointestinal disorders

(especially diarrhoea and irritable bowel syndrome), the

modulation of gastric acid secretion and the treatment of hyperreninaemia and leukemia.

The compounds of the present invention are of the formula:

wherein A com pletes a 4 to 7 mem bered carbocyclic ring which may be saturated or mon o-unsaturated and which may optionally be fused to a further saturated or un saturated 5 or 6 membered carbocyclic ring ;

B is (CH₂) _m wherein m is an integer of from 1 to 3;

each of R and R⁴ is independently H, C₁-C₆ alkyl, benzyl or an alternative biolabile ester-forming group;

R¹ is H or C₁-C₄ alkyl; R² is C₁-C₆ alkyl substituted by C₁ -C₄ alkoxy, aryl or aryloxy;

and R⁵ is C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl,

C₃-C₇ cycloalkyl, or C₃-C₇ cycdoalkenyl,

or R⁵ is C₁-C₆ alkyl substituted by halo, hydroxy, C₁-C₆ alkoxy, C₁-C₆ alkoxy(C₁-C₆)alkoxy, C₃-C₇ cycloalkyl, C₃-C₇ cydoalkenyl, aryl, aryloxy, heterocyclyl, -NR⁶R⁷ ,

-NR⁸COR⁹, -NR⁸SO₂R¹⁰, -CONR⁶R⁷ or R⁶R⁷N-(C₁-C₆)alkoxy; or R⁵ is C₁-C₆ alkyl substituted by a group of the formula:

R

wherein R⁶ and R⁷ are each independently H, C₁-C₄ alkyl, C₃-C₇ cycloalkyl, aryl, aryl(C₁-C₄)alkyl, C₂-C₆ alkoxyalkyl, or heterocyclyl; or the two groups R⁶ and R⁷ are taken together with the nitrogen to which they are attached to form a pryrrolidinyl, piperidino, morpholino, piperazinyl or N-(C₁-C₄)alkyl-piperazinyl group;

R⁸ is H or C₁-C₄ alkyl;

R⁹ is C₁-C₄ alkyl, CF₃, aryl, aryl(C₁-C₄)alkyl, aryl(C₁-C₄)alkoxy, heteorcyclyl, C₁-C₄ alkoxy or NR ⁶R⁷ wherein R⁶ and R⁷ are as previcusly defined;

R¹⁰ is C₁-C₄ alkyl, C₃-C₇ cycloalkyl, aryl or heterocyclyl;

R¹¹ is H, C₁-C₆ alkyl, aryl or C₃-C₇ cycloalkyl;

R¹² is R¹¹ CONR¹¹-, R¹¹SO₂NR¹¹-, R¹⁶R¹⁷N-(CH₂)_p -, or

R¹¹0-, wherein each R¹¹ is as previously defined above; R¹³ and R¹⁴ are each independently H or C₁-C₆ alkyl; or R¹³ is H and R¹⁴ is C₁ -C₆ alkyl which is substituted by

OH, C₁-C₄ alkoxy, SH, SCH₃, NH₂, aryl(C₁-C₆)alkyl-

OCONH-, NH₂CO-, CO₂H, guanidino, aryl, or heterocyclyl; or the two groups R¹³ and R¹⁴ are joined together to form, with the carbon atom to which they are attached, a

5 or 6 membered carbocyclic ring which may be saturated or mono -unsaturated and which may optionally be substituted byC₁-C₄ alkyl or fused to a further 5 or 6 membered saturated or unsaturated carbocyclic ring; or R¹³ is H, and R¹² and R¹⁴ are linked to form a

2-(N-COR¹¹-4-aminopyrrolidinyl) group;

R¹⁵ is R¹⁶R¹⁷NCO-, R¹¹OCO-, R¹¹OCH₂- or heterocyclyl, wherein R¹¹ is as previously defined above; R¹⁶ and R¹⁷ are each independently H or C₁-C₆ alkyl; and p is 0 or an integer of from 1 to 6;

and pharmaceutically acceptable salts thereof and bioprecursors therefor.

In the above definition, unless otherwise indicated, alkyl groups having three or more carbon atoms may be straight or branched-chain. The term aryl as used herein means an aromatic hydrocarbcai group such as phenyl, naphthyl or biphenyl which may optionally be substituted with one or more OH, CN, CF₃ , C₁-C₄ alkyl, C₁-C₄ alkoxy groups or halo atoms. Halo means fluoro, chloro, bromo or iodo.

The term heterocyclyl means a 5 or 6 membered nitrogen, oxygen or sulphur containing heterocyclic group which, unless otherwise stated, may be saturated or unsaturated and which may optionally include a further oxygen or one to three nitrogen atoms in the ring and which may optionally be benzofused or substituted with for example, one or more halo, C₁-C₄ alkyl, hydroxy, carbamqyl, benzyl, oxo, amino or mono or di-(C₁-C₄ alkyl)amino or (C₁-C₄ alkancyl)amino groups. Particular examples of heterocycles include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, furanyl,

tetrahydrofuranyl, tetrahydropyranyl, dioxanyl, thienyl, oxazolyl, isoxazolyl, thiazolyl, indolyl, isoindolinyl, quinolyl,

quinoxalinyl, quinazolinyl and benzimidazolyl, each being optionally substituted as previously defined.

The compounds of formula (I) may contain several asymmetric centres and thus they can exist as enantiomers and diastereomers. The invention includes both mixtures and the separated individual isomers. The substituents R², and CO₂R⁴ may have cis or trans geometry relative to the amide attachment.

The pharmaceutically acceptable salts of the compounds of formula (I) containing an acidic centre are those formed with bases which form non-toxic salts. Examples include the alkali metal salts such as the sodium, potassium or calcium salts or salts with amines such as diethylamine. compounds having a basic centre can also form acid addition salts with pharmaceutically acceptable acids. Examples include the hydrochloride

hydrobromide, sulphate or bisulphate, phosphate or hydrogen phosphate, acetate, citrate, fumarate, gluconate, lactate. maleate, succinate and tartrate salts.

The term bioprecursor in the above definition means a pharmaceutically acceptable biologically degradable derivative of the compound of formula (I) which, upon administration to an animal or human being, is converted in the body to produce a ccnpound of the formula (I).

A preferred group of compounds of the formula (I) are those wherein A is (CH₂)₄, R¹ is H and B is (CH₂)₂, i.e. compounds of the formula (II) below wherein R, R², R⁴ and R⁵ are as previously defined for formula (I) :

Also preferred are those compounds of formulae (I) and (II) wherein R and R⁴ are both H (diacids) as well as biolabile mono and di-ester derivatives thereof wherein one or both of R and R⁴ is a biolabile ester-forming group.

The term biolabile ester-forming group is well understood in the art as meaning a group which provides an ester which can be readily cleaved in the body to liberate the corresponding diacid of formula (I) wherein R and R⁴ are both H. A number of such ester groups are well known, for example in the penicillin area or in the case of the ACE-inhibitor antihypertensive agents.

In the case of the compounds of formulae (I) and (II) such biolabile pro-drug esters are particularly advantageous in providing compounds of the formula (I) suitable for oral

administration. The suitability of any particular ester-foming group can be assessed by conventional animal or in vitro enzyme hydrolysis studies. Thus, desirably for optimum effect, the ester should only be hydrolysed after absorption, accordingly, the ester should be resistant to hydrolysis before absorption by digestive enzymes but should be readily hydrolysed by, for example, liver enzymes. In this way the active diacid is released into the bloodstream following oral absorption.

In addition to lower alkyl esters (particularly ethyl) and benzyl esters, suitable biolabile esters include alkanoyloxyalkyl esters, including alkyl, cycloalkyl and aryl substituted

derivatives thereof, aryloxyalkyl esters, aroyloxyalkyl esters, arylalkyloxyalkyl esters, arylesters, aralkylesters, and haloalkyl esters wherein said alkancyl or alkyl groups have from 1 to 8 carbon atoms and are branched or straight chain and said aryl groups are phenyl, naphthyl or indanyl optionally substituted with one or more C₁-C₄ alkyl or C₁-C₄ alkoxy groups or halo atoms.

Thus examples of R and R⁴ when they are biolabile

ester-forming groups other than ethyl and benzyl include:

1-(2,2-diethylbutyryloxy)ethyl, 2-ethylpropionyloxymethyl,

1-(2-ethylpropionyloxy)ethyl, 1-(2,4-dimethylbenzcyloxy)ethyl, 1-

(benzoyloxy)benzyl, 1-(benzoyloxy)ethyl, 2-methyl-1-prcpionyloxyprcpyl, 2,4,6-trimethylbenzcyloxymethyl, 1-(2,4,6-trimethyl benzyloxy)ethyl, pivaloyloxymethyl, phenethyl, pherpropyl, 2,2,2- trifluoroethyl, 1- or 2-naphthyl, 2,4-dimethylphenyl, 4-t-butyl- phenyl, [5-(4-methyl-1,3-dioxolen-2-onyl)]methyl and 5-indanyl.

Compounds of the formulae (I) and (II) wherein R is benzyl or t-butyl and R⁴ is ethyl are valuable intermediates for the preparation of the diacids wherein R and R⁴ are both H.

In a further preferred group of compounds R⁵ is methylene substituted by a group of the formula -NHCOCR¹²R ¹³R¹⁴'

particularly where R¹² is NH₂, R¹¹CONH- or R¹¹SO₂NH-, R¹³ is H and R¹⁴ is -(CH₂)₄NH₂. Particularly preferred are such groups derived from S-lysine; thus especially preferred R⁵ substitutents of this type include N²-acetyl-S-lysylaminomethyl, N²-methanesulphonyl-S- lysyl-aminomethyl, N²-phenylsulphonyl-S-lysyl-aminomethyl andN²-cyclobutylcarbonyl-S-lysyl-aminomethyl.

In further groups of preferred compounds R⁵ is C₁-C₆ alkyl substituted by C₁-C₈ alkoxy, particularly methαxyethyl; or R⁵ is

C₁-C₆ alkyl substituted by C₁-C₆ alkoxy(C₁-C₆)alkoxy, particularly 2-methyoxyethoxymethyl; or wherein R is C₁-C₆ alkyl substituted by -NHCDCR¹²R¹³R¹⁴ wherein R¹² is NH₂, R¹³ is CH₃ and R¹⁴ is H or

CH₃ inclviding in particular R-alanyl-aminomethyl and (2-amino-2- methylprcpanoyl)aminomethyl.

R² is preferably phenyl, benzyl, phenethyl, methoxypropyl or ethoxypropyl.

Particularly preferred individual compounds of the invention include:

2S-(N²-methanesulphonyl-S-lysylaminome thyl)-3-{1-[cis-4- carboxy-3-cis{3-ethoxypropyl}-cyclohexyl)carbamoyl]cyclopentyl}- propanoic acid. 2-(N²-methanesulphoryl-S-lysylaminomethyl)-3-{1-[(cis-4- carboxy-3-cis-phenesthyl-cyclohexyl)carbamoyl]cyclopentyl}propanoic acid,

2S-(2-methoxyethoxymethyl)-3-{1-[(cis-4-carboxy-3-cis-{3- ethoxypropyl}cyclohexyl)carbamoyl]cyclopentyl}propanoic acid and

2S-(2-methoxyethoxymethyl)-3-{1-[(cis-4-carboxy-3-cis-{3- methoxypropyl}-cyclohexyl)carbamoyl]cyclopentyl}propanoic acid, and biolabile ester derivatives thereof.

The compounds of formula (I) are prepared by a number of different processes. The basic procedure involves the synthesis of a partially protected cycloalkyl-substituted glutaric acid derivative which is coupled to an amine to give the desired glutaramide. The carboxylic acid group in the amine, if free, or any reactive groups m R⁵, may require protection during the coupling step and such protecting groups are removed in the final stage of the process.

The synthetic route is illustrated in scheme 1 wherein A, B,

R¹ and R² are as previously defined, R^5' is as defined for R⁵ with any reactive group therein protected if necessary and R¹⁸ and R¹⁹ are as defined for R and R⁴ excluding H, or they are conventional carboxylic acid protecting groups: Scheme 1

The reaction of the compounds of formula (III) and (IV) is achieved using conventional amide coupling techniques. Thus in one process the reaction is achieved with the reactants dissolved in an organic solvent, e.g. dichlorotnethane, using a diimide condensing agent, for example 1-ethyl-3-(dimethylaminopropyl)- carbodiimide, or N,N'-dicyclohexylcarboodiimide, advantageously in the presence of 1-hydroxybenzotriazole and an organic base such as N-methylmorpholine. The reaction is generally complete after a period of from 12 to 24 hours at room temperature and the product is then isolated by conventional procedures, i.e. by washing with water or filtration to remove the urea biproduct and evaporation of the solvent. The product may be further purified by crystallisation or chromatography, if necessary. The compounds of formula (V) include compounds of formula (I) wherein R and R⁴ are C₁-C₆ alkyl or benzyl.

In some cases the coupled product, in protected form, may be subjected to conventional chemical transformation reactions to allcw preparation of further compounds of formula (V). Thus for example compounds of formula (V) wherein R^5' contains an ester group may be hydrolysed or hydrogenated to generate the carboxylic acid which may be further reacted, for example with an amine, to give amide derivatives.

Similarly compounds wherein R^5' contains a subs tituted or protected amino group (for example a benzylamino, dibenzylamino, benzyloxycarbonylamino or t-butyloxycarbonylamino group) may be converted to the free amines by hydrogenation or protonolysis as appropriate. The amines produced may be further reacted, thus for example reaction with a sulphonyl halide yields the corresponding sulphonamides, acylaticn with an acid chloride or anhydride yields the corresponding amides, reaction with an isocyanate yields urea derivatives and reaction with a chlorofornate yields the alkoxycarbonylamino and products respectively. All these

transformations are entirely conventional and appropriate

conditions and reagents for their performance will be well known to those skilled in the art as will other variations and

possibilities.

The diesters of formula (V) may be further reacted to give the monoester of diacid derivatives of formula (I) wherein one or both of R and R⁴ are H. The conditions used will depend on the precise nature of the groups R¹⁸ and R¹⁹ present in the compound of formula (V) and a number of variations are possible. Thus for example when both of R¹⁸ and R¹⁹ are benzyl, hydrogenation of the product will yield the diacid of formula (I) wherein R and R⁴ are both H. Mternatively if one of R¹⁸ and R¹⁹ is benzyl and the other is alkyl, hydrogenation will yield a monoester product.

This can be hydrolysed, if desired, again to yield the diacid product. When one of R¹⁸ and R¹⁹ is t-b tyl, treatment of the compound of formula (V) with trifluoroacetic acid yields the corresponding acid. The diester product wherein R¹⁸ and R¹⁹ are benzyl or lower alkyl can also be treated with trimethylsilyl iodide to produce the dicarboxylic acid product. If some other carboxylic acid protecting group is used for R¹⁸ or R¹⁹ then clearly appropriate conditions for its removal must be employed in the final step to give the ester or diacid product of formula (I). In the case where the ring A or the substituent R⁵ is unsaturated, the deprotectiαn must be effected by non-reductive methods, thus for example if either of R and R⁴ is benzyl, they may be removed by treatment with trimethylsilyl iodide.

As well as removing any protecting group which may be present in R^5', a number of chemical transformation reactions are possible on the final mono-ester or diacid products as previously

described. In each case the product may be obtained as the free carboxylic acid or it may be neutralised with an appropriate base and isolated in salt form. In a variant of the above procedure, compounds of the formula

(I) wherein R⁵ is C₁-C₆ alkyl substituted by -NR⁸COR⁹, -NR⁸SO₂R¹⁰, -NR¹¹COCR¹²R¹³R¹⁴ or -NR¹¹SO₂CR¹²R¹³R¹⁴ are prepared by a procss which involves acylating or sulphonylating a compound of the formula:

wherein R²⁰ is as defined for R⁸or R¹¹, R¹⁸ and R¹⁹ are as previously defined and Y is a C₁-C₆ alkyl group; by reaction with an acid of the formula R⁹CO₂H, R¹⁰SO₃H, R¹²R¹³R¹⁴CCO₂H, or

R¹²R¹³R¹⁴CSO₃H, or an activated derivative thereof. The resulting amide or sulphonamide product is then d-protected if required and the diester product cleaved to yield the carboxylic acids of formula (I) wherein R and R⁴ are each H as previously described.

The ccmpcunds of formula (VI) are prepared following the procedures shown in scheme 1 but using a compound of formula (III) having R^5' as a protected amine derivative. Thus, for example R^5' can contain a bis-(1S)-phenylethylamino substituent.

Hydrogennation of the coupled product gives the corresponding free amine of formula (VI) wherein R²⁰ is H and Y is CH₂. This route is of particular value for the preparation of compounds having

2(S) stereochemistry in the glutaramide backbone. The starting cycloalkyl-substituted glutaric acid mono esters of formula III may be prepared as described in cur European patent applications EP-A-0274234, 89305180.5 and 89304698.7.

The amines of formula (IV) are generally novel compounds (particularly when the substituents have defined stereochemistry) and they are prepared by appropriate synthetic procedures in accordance with literature precedents. Thus in one procedure the corresponding ketone is converted to the amine via reduction of the oxime. In an alternative process the corresponding alcohol is reacted with methyl toluenesulphonate in the presence of diethyl diazodicarboxylate and triphenylphosphine; the resulting

4-methyIbenzenesulphonyloxy derivative is reacted with sodium azide and the product reduced to yield the amine. These

procedures are illustrated in the Preparations give hereafter.

Appropriate coupling and protecting methods for all of the above steps and alternative variations and procedures will be well known to those skilled in the art by reference to standard text books and to the examples provided hereafter.

As previously mentioned, the compounds of the invention are potent inhibitors of the neutral endcpeptidase (E.C.3.4.24.11). This enzyme is involved in the breakdown of a number of peptide hormones and, in particular it is involved in the breakdown of atrial natriuretic factor (ANF). This hormone consists of a family of related natriuretic peptides, secreted ry the heart, of which the major circulating form in humans is known to be the 28 amino-acid peptide referred to as α-hANP. Thus, by preventing the degradation of ANF, by endopeptidase E.C.3.4.24.11, the compounds of the invention can potentiate its biological effects and the compounds are thus diuretic and natriuretic agents of utility in a number of disorders as previously described.

Activity against neutral endopeptidase E.C.3.4.24.11 is assessed using a procedure based on the assay described by J.T. Gafford, R.A. Skidgel, E.G. Erdos and L.B. Hersh, Biochemistry, 1983, 32, 3265-3271. The method involves determining the concentration of compound required to reduce by 50% the rate of release of radiolabelled hippuric acid from hippuryl-L- pheιylalanyl-L-argjnine by a neutral endcpeptidase preparation from rat kidney.

The activity of the compounds as diuretic agents is

determined by measuring their ability to increase urine output and sodium ion excretion in saline loaded conscious mice. In this test, male mice (Charles River CDl, 22-28 g) are acclimatised and starved overnight in metabowls. The mice are dosed intravenously via the tail vein, with the test compound dissolved in a volume of saline solution equivalent to 2.5% of body weight. Urine samples are collected each hour for two hours in pre-weighed tubes and analysed for electrolyte concentration. Urine volume and sodium ion concentration from the test animals are compared to a control group which received only saline.

For administration to man in the curative of prophylactic treatment of hypertension, congestive heart failure or renal insufficiency, oral dosages of the compounds will generally be in the range of from 4-800 mg daily for an average adult patient (70 kg). Thus for a typical adult patient, individual tablets or capsules contain from 2 to 400 mg of active compound, in a suitable pharmaceutically acceptable vehicle or carrier for administration singly, or in multiple doses, once or several times a day. Dosages for intravenous administration would typically be within the range 1 to 400 mg per single dose as required. In practice the physician will determine the actual dosage which will be most suitable for an individual patient and it will vary with the age, weight and response of the particular patient. The above dosages are exemplary of the average case but there can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention. For human use, the compounds of the formula (I) can be administered alone, but will generally be administered in

admixture with a pharmaceutical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. For example, they may be administered orally in the form of tablets contai ning such excipients as starch or lactose, or in capsules or ovules either alone or in admixture with excipients, or in the form of elixirs or suspensions containing flavouring or colouring agents. They may be injected

parenterally, for example, intravenously, intramus cularly or subcutaneously. For parenteral administration, they are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or glucose to make the solution isotonic with blood.

The compounds may be administered alone but may also be administered together with such other agents as the physician shall direct to optimise control of blood pressure or to treat congestive heart failure, renal insufficiency or other disorders in any particular patient in accordance with established medical practice. Thus the compounds can be co-administered with a variety of cardiovascular agents, for example with an ACE inhibitor such as captopril or enalapril to facilitate the control of blood pressure in treatment of hypertension; or with digitalis, or another cardiac stimulant or with an ACE inhibitor, for the treatment of congestive heart failure. Other possibilities include co-administration with a calcium antagonist (e.g. nifedipine, amlodopine or diltiazem) a beta-blocker (e.g.

atenolol) or an alpha-blocker (e.g. prazosin or doxazosin) as shall be determined by the physician as appropriate for the treatment of the particular patient or condition involved.

In addition to the above, thecompounds may also be

admmistered in conjunction with exogenous ANF, or a derivative thereof or related peptide or peptide fragment having

diuretic/natriuretic activity or with other ANF-gene related peptides (e.g. as described by D. L. Vesely et al, Biochem.

Biophys. Res. Comm., 1987, 143, 186).

Thus in a further aspect the invention provides a

pharmaceutical composition comprising a compound of the formula (I), or a pharmaceutically acceptable salt thereof or bioprecursor therefor, together with a phar macoutically acceptable diluent or carrier.

The invention also includes a compound of the formula (I), or a pha rmacoutically acceptable salt thereof or bicprecursor therefor, for use in medicine, particularly for use as a diuretic agent for the treatment of hypertension, congestive heart failure or renal insufficiency in a human being.

The invention further includes the use of a compound of the formula (I) for the manufacture of a medicament for the treatment of hypertension, heart failure, angina, renal insufficiency, preinenstrual syndrome, cyclical oedema, Menieres disease, hyperaldosteronism, pulmonary oedema, ascites, hyperoaciuria, glaucoma, asthma, inflammation, pain, epilepsy, affective disorders, dementia and geriatric confusion, obesity. gastrointestinal disorders (including diarrhoea), hyperreninaemia, leukemia, and the modulation of gastric acid secretion.

The preparation of the compounds of the invention will now be more particularly illustrated by reference to the following experimental examples, in which Preparations 1-8 describe preparation of the starting amines of formula (IV) and Examples 1-45 describe preparations of compounds of the formula (I). The purity of compounds was routinely monitored by thin layer chromatography using Merck Kieselgel 60 F₂₅₄ plates. Solvent system ss-1 was a mixture of dichloromethane, methanol and glacial acetic acid (90:10:1), ss-2 was the upper phase of a mixture consisting of methyl iso-butyl ketone, glacial acetic acid and water (2:1:1), and ss-3 was a mixture of ethyl acetate and hexane (1:1). ¹H-Nuclear magnetic reasonance spectra were recorded using a Nicolet QE-300 spectrometer and were in all cases consistent with the proposed structures.

PREPARATION 1 c-4-Amino-c-2-(2-phenylethyl)cyclohexane-r-1-carboxylic acid ethyl ester hydrochloride i. 4-Oxo-2-(2-phenylethyl)cyclohex-2-ene carboxylic acid ethyl ester

An 80% dispersion of sodium hydride in oil (307 mg, 10 mmole) was added under nitrogen to an ice cold stirred mixture of

3-oxo-5-phenyl pentanoic acid ethyl ester (28.4 g , 129 mmole) and absolute ethanol (1 ml). Methyl vinyl ketone (10.7 ml, 129 mmole) was then added dropwise over half an hour with continued ice cooling and, after stirring for an hour at room temperature, acetic acid (1.4 ml), pyrrolidine (775 mg), ethanol(17 ml) and water (2 ml) were added. After refluxing for 2 hours, the solvent was evaporated under vacuum and the residue dissolved in diethyl ether. Washing sequentially with 2N hydrochloric acid, water, saturated aqueous sodium bicarbonate and water, drying over MgSO₄ and evaporation gave a yellow liquid (34.6 g). Chromatography on silica gel (600 g) eluting with a mdxture of diethyl ether and hexane (1:3 by volume) gave the required enone as a clear liquid (18.54 g,) Rf 0.35 (1:1 diethyl ether:hexane). Found: C,74.88; H,7.40. C₁₇H₂₀O₃ requires C,74.97; H,7.40%. ii. 4-Oxo-cis-2-(2-phenylethyl)cyclohexanecarboxylic acid ethyl ester

The enone (18.44 g, 6.76 mmole) from part (i) in ethanol (80 ml) containing 2N hydrochloric acid (3 ml) was hydrogenated over 5% palladium on charcoal catalyst (500 mg) at 50 p.s.i. (3.45 bar) pressure. After three hours a further amount of catalyst (250 mg) was added and reduction was continued for a further two hours. The suspension was filtered through Avicel and the filtrate evaporated under vacuum. The residual oil was dissolved in diethyl ether, washed with saturated aqueous sodium bicarbonate and water, dried over MgSO₄ and evaporated to give a clear liquid (18.52 g). Chromatography on silica gel (600 g), eluting with an increasing proportion of diethyl ether in hexane (2:8 - 4:6) gave the required ketone as a liquid. (16.78 g,90%). Rf 0.4 (1:1 diethyl ether:hexane).

iii. 4-Methoxyimino-cis-2-(2-phenylethyl)cyclohexane carboxylic acid ethyl ester

The above ketone (3.02 g, 11 mmole), methoxylamine

hydrochloride (1.19 g, 14.3 mmole) and sodium acetate (1.17 g; 14.3 mmole) were refluxed for five hours in ethanol (50 ml). the solvent was evaporated under vacuum, the residue taken up in diethyl ether and washed with saturated aqueous sodium bicarbonate followed by water. Drying over MgSO₄ and evaporation under vacuum gave the 0-methyl oxime as an oil (3.32 g, 99%) Rf 0.55 and 0.66 (1:1 diethyl ether, hexane). Found: C,71.23; H,8.33; N,4.88. C₁₈H₂₅NO₃ requires C,71.26; H,8.30; N,4.62%. iv. c -4-Butoxycar bonylamino-c-2-(2-phenylethyl)-cyclohexane- r-1-carboxylic acid ethyl ester

Trifluroacetic acid (4.2 ml, 54 mmole) in dry tetrahydrofuran (10 ml) was added dropwise with ice cooling to a stirred

suspension of sodium borohydride (2.04 g, 54 mmole) in dry tetrahydrofuran. The temperature was kept between 5 and 10°C and after stirring for fifteen minutes the 0-methyloxime from part (iii) (3.28 g; 10.8 mmole) in tetrahydrofuran (10 ml) was added dropwise over ten minutes. The temperature rose to 20ºC and, after stirring for five hours, water was very carefully added with ice cooling and the mixture was partitioned between ethyl acetate and water. The aqueous layer was extracted twice with ethyl acetate, the combined organic extracts washed with saturated salt solution, dried over MgSO₄ and evaporated to give a gum (3.25 g). The crude amine was dissolved in methylene chloride (50 ml)

N-methylmorpholine (2.2 g, 21.6 mmole) and di-t-butyl dicarbonate (4.7 g, 21.6 mmole) were added and the mixture allowed to stand at room temperature for 48 hours. The solvent was evaporated under vacuum, the residue partitioned between diethyl ether and water and the organic extract washed sequentially with 0.5N hydrochloric acid, water, saturated aqueous sodium bicarbonate and water.

Drying over MgSO₄ and evaporation gave a gum (3.9 g). The required cis- compound was separated from the minor more polar trans-isomer by chromatography on silica gel (400 g). Elution with a mixture of diethyl ether in hexane (3:7 by volume) gave the protected amine as an oil (1.94 g, 48%). Rf 0.35 (3:7 diethyl ether:hexane). Found: C,70.43; H,8.75; N,3.45. C₂₂H₃₃ NO₄ requires C,70.37; H,8.86; N,3.73%. v. c-4-Amino-c-2-(2-phenylethyl)cyclohexane-r-1-carboxylic acid ethyl ester hydrochloride

An ice cold stirred solution of the above ester (1.94 g, 5.17 mm ole) in diethyl ether was saturated with hydrogen chloride. After three hours the solvent was blown off with nitrogen and the residue triturated with diethyl ether and collected by filtration giving the title amine salt as a white solid (1.44 g, 89%). m.p. 213-214°C. Rf 0.5 (ss-1). Found; C,65.84; H,8.74; N,4.43.

C₁₇H₂₅NO₂.HCl requires C,65.48; H,8.40; N,4.49%.

PREPARATION 2

c-4-Amino-c-2-(3-methoxypropyl)cyclohexane-r-1-carboxylic acid ethyl ester hydrochloride

The procedure of Preparation 1 was followed but using

3-oxo-6-roethoxy-hexanoic acid ethyl ester as the starting material in part (i) to give the title amine as white solid, m.p.

206-208°C. Rf 0.2 (ss-1). Found: C,55.15; H,9.11; N,5.34.

C₁₃H₂₅NO₃. HCl, 0.2 H₂O requires C,55.09; H,9.39; N,5.94%.

PREPARATION 3

c-4-Amino-c-2-(3-ethoxypropyl)cyclohexane-r-1-carboxylic acid ethyl ester hydrochloride

The procedure of Preparation 1 was followed but using

3-oxo-6-ethoxyhexanoic acid ethyl ester as the starting material in part (i) to give the title amine as a white solid, m.p.

201-203°C. Rf 0.2 (ss-1). Found: C,55.50; H,9.52; N,4.33.

C₁₄ H₂₇NO₃.HCl.0.5H₂O requires C,55.52; H,9.65; N,4.63%. PREPARATION 4

c-4-Amino-c-2-(2-phenylethyl)cyclohexane-r-1-carboxylic acid methyl ester hydrochloride

A solution of the ethyl ester from Preparation 1 (1.4 g; 4.48 mmole) in dry methanol (50 ml) was saturated with hydrogen chloride and heated at 55 to 60°C for four days and then refluxed for a further 3 days. Hydrogen chloride was periodically introduced to maintain saturation. The solution was evaporated to dryness under vacuum, the residue dried azexstropically with methylene chloride, and the residue triturated with diethyl ether to give the methyl ester as a white pcwder (1.29 g, 97%) m.p. 202-4°C. Rf 0.15 (ss-1). Found: C,63.70; H,8.13; N,4.74.

C₁₆H₂₃NO₂. HCl.0.25 H₂O requires C,63.56; H,8.17; N,4.63%. PREPARATlON 5

c-4-Amino-t-2-(2-thenylethyl)cyclohexane-r-1-carboxylic acid ethyl ester i. cis-7-(2-Phenylethyl)-1,4-dioxaspiro[4,5] decane-8- carboxylic acid ethyl ester

The ketone of Preparation 1 part ii (10.97 g; 40 mmole) , ethylene glycol (2.73 g, 44 mmole) and 4-toluenesulphonic acid (100 mg) were refluxed in benzene (80 ml) using a Dean-Stark water trap. After eigh t hours the solution was cooled, diluted with diethyl ether and washed sequentially with saturated aqueous sodium bicarbonate and water. Drying over MgSO₄ and evaporation under vacuum gave a clear liquid (12.22 g, 96%) Rf 0.32 (3:7, diethyl ether, hexane) . Found: C,71.45; H,8.30. C_{1 9}H₂₆O₄ requires C,71.67; H,8.23%.

ii. trans-7-(2-Phenylethyl)-1,4-dioxaspiro[4,5]decane-8

carboxylic acid ethyl ester

Potassium t-butoxide (1.9 g, 17 mmole) was added to a solution of the above ester (12.17g, 38.2 mmole) in dry t-butanol (90 ml) and the mixture refluxed under nitrogen for forty eight hours. Neutralisation with 2N hydrochloric acid and evaporation under vacuum gave a light brown oil which was dissolved in diethyl ether and washed with water. Drying over MgSO₄ and evaporation gave an oil (12.09 g) which was chromatographed on silica gel (600 g). Elutions with a mixture of diethyl ether and hexane (3:7 by volume) gave the required trans-isomer as an oil (8.44 g, 69%). Rf 0.29 (3:7 diethyl ether, hexane). Found: C,71.60; H,8.14.

C₁₉H₂₆O₄ requires C,71.67; H,8.23%. iii. 4-Oxo-trans-2-(2-phenylethyl)cyclohexanecarboxylic acid ethyl ester

The above ester (8.40 g, 26.4 mmole) was refluxed in IN sulphuric acid (50 ml) amd ethanol (70 ml). After three hcurs most of the ethanol was evaporated off under vacuum, water was added and the suspension extracted with diethyl ether. The organic extract was washed sequentially with water, saturated aqueous sodium bicarbonate and water, dried over MgSO₄ and evaporated under vacuum to give a clear oil (6.46 g, 89%) Rf 0.38 (1:1 diethyl ether, hexane). Found: C,74.25; H,8.07. C₁₇ H₂₂O₃ requires C,74.42; H,8.08%. iv. t-2-(2-Phenylethyl)-c-4-phenylmethylamino-cyclohexane-r- 1-carboxylic acid ethyl ester

3A molecular sieve (3 g) was added to a stirred solution of the ketone from part iii (3.2 g, 11.66 mmole) and benzylamine (1.27 ml, 11.66 mmole) in ethanol (15 ml). After three and a half hours at room temperature, the solution was pipetted off into a dry hydrogenation vessel washing the sieves with a little ethanol (2x5 ml). Platinum oxide (500 mg) was added and the reduction completed in three hours at 50 p.s.i. (3.45 bar). The mixture was filtered through arbacel, evaporated under vacuum and the residual liquid chromatographed on silica gel (200 g). Elution with increasing proportions of ethyl acetate in hexane (7:3 - 1:1 by volume) gave the required cis-isomer as a clear oil (3.17 g, 74%) Rf 0.3 (ss-3) Found: C,78.85; H,8.53; N,4.86. C₂₄H₃₁NO₂ requires C,78.86; H,8.55; N,3.83%.

v. c-4-Amino-t-2-(2-phenylethyl)cyclohexane-r-1-carboxylic acid ethyl ester

A solution of the above amine (3.13 g, 8.56 mmole) in ethanol (80ml) containing IN hydrochloric acid (9.42 ml, 9.42 mmole) was hydrogenated over 20% palladium hydroxide and charcoal catalyst (600 mg) at 50 p.s.i. (3.45 bar) pressure. Further amounts of catalyst (500 mg) were added after six and twenty four hours. After a further twenty two hours the suspension was filtered through arbacel and the filtrate evaporated to dryness under vacuum. The residue was recrystallised from a mixture of ethanol and diethyl ether to give the required amine as a white solid (2.03 g, 76%) m.p. 175-7°C. Rf 0.25 (ss-1) . Found: C,64.42; H,8.50; N,4.52. C₁₇H₂₅NO₂. HCl.0.25H₂O requires C,64.54; H,8.44; N,4.43%.

PREPARATION 6

c-4-Ami no-c-2-p henylcyclohexane-r-1-carboxylic acid methyl ester hydrochloride

i. 4-Oxo-2-pherylc ycloh ex-2-ene-carboxylic acid methyl ester

2-Hydro xy-4-oxo-2-pherylcyclohexane carboxylic acid methyl ester (17.5 g, 70.48 mmole) [J. Org. Chem. , 39 2427 (1974) ] was stirred for 15 minutes at 80º C with polyphosphoric acid (17.5 g) . On cooling the mixture was partitioned between ethyl acetate and water. The organic extract was washed sequentially with water, saturated aqueous sodium bicarbonate and water, dried over MgSO₄ and on evaporation gave an oil. c hromatography on silica gel eluting with increasing proportions of ethyl acetate in hexane

(2:8 - 3:7 by volume) gave the required compound as a golden oil

(9.0 g, 56%) Rf 0.5 (ss-3) . ii. 4-Oxo-2-pherylcyclohexanecarbooxylic acid mether ester

The enone of part 1 (9.0 g, 39.08 mmole) in methanol (40 ml) containing 2N hydrochloric acid (1.5 ml) was hydrogenated over 5% palladium on charcoal catalyst at 50 p.s.i. (3.45 bar). After three hours the suspension was filtered through Arbacel and evaporated to dryness under vacuum. The residual oil was chromatographed on silica gel (400 g). Elution with increasing proportions of ethyl acetate in hexane (2:8 - 4:6 by volume) gave the required ketone as a white solid (4.04 g, 49%) Rf 0.55 (ss-3) Found: C,72.39; H,6.95. C₁₄H₁₆O₃ requires C,72.39; H,6.94%.

iii. c-4-Hydroxy-c-2-phenylcyclohexane-r-1-carboxylic acid methyl ester

Sodium borohydride (2.33 g, 61.51 mmole) was added in small portions to a stirred solution of the ketone of part ii (3.78 g, 16.27 mmole) in methanol (80 ml), keeping the temperature below 5ºC. After fifteen minutes the solvent was evaporated under vacuum, the residue dissolved in methylene chloride and washed with saturated salt solution. Drying over MgSO₄ and evaporation under vacuum gave a white solid. Chromatography on silica gel (250 g) eluting with diethyl ether in hexane (1:1 by volume) gave the required ester as a foam (2.93 g, 77%). Found: C,71.84;

H,7.82. C₁₄H₁₈O₃ requires C,71.77; H,7.74%. iv. t-4-(4-Methylbenzene ulphonyloxy)-c-2-phenylcyclohexane-r-1 carboxylic acid methyl ester

Diethyl diazodicarboxylate (4.08 g, 23.47 mmole) in

tetrahydrofuran (10 ml) was added under nitrogen to a stirred solution of the ester of part iii (4.4 g, 18.78 mmole),

triphenylphosphine (6.16 g, 23.47 mmole) and methyl 4-toluene sulphonate (4.37 g, 23.47 mmole) in tetrahydrofuran (60 ml) keeping the temperature between 5 and 10 C. After stirring overnight at room temperature the mixture was re-cooled to 0°C and further amounts of triphenylphosphine (1.23 g, 4.7 mmole) and methyl 4-toluene sulphonate (874 mg, 4.7 mmole) were added followed by diethyl diazodicarboxylate (816 mg, 4.7 mmole). After stirring at room temperature for a further four hours, the mixture was evaporated to a small volume, the residue redissolved in methylene chloride and applied directly to a silica gel (400 g) chromatography column. Elution with increasing proportions of ethyl acetate in hexane (1:9 - 3:7 by volume) gave the required 4-toluenesulphonate as an oil (3.45g, 47%). Rf 0.45 (4:1 ethyl acetate, hexane) Found: C,64.71; H,6.26. C₂₁H₂₄O₅S requires;

C,64.93; H,6.23%. v. c-4-Azido-c-2-phenylcyclohrxane-r-1-carboxylic acid methyl ester

Sodium azide (1.16 g, 17.76 mmole) was added to a stirred solution of the 4-toluenesulphonate from part iv (3.45 g, 8.88 mmole) in dimethylformamide, and the mixture was stirred at 60°C for eighteen hours. On cooling water was added and the suspension extracted with diethyl ether. The organic extract was washed with water, dried over MgSO₄ and evaporation gave a clear oil which was chromatographed on silica gel (300 g). Elution with increasing proportions of ethyl acetate in hexane (1:20 - 1:4 by volume) gave the azide as waxy solid (2.11 g, 92%). Rf 0.55 (4:1 hexane, ethyl acetate). Found: C,65.20; H, 6.60; N,15.32. C₁₄H₁₇ N₃O₂ requires C, 64.85; H,6.61; N,16.20%. vi. c-4-Amino-c-2-phenylcyclohexane-r-1-carboxylic acid methyl ester hydrochloride

The azide from part v (2.1 g, 8.1 m mmole) in methanol (50 ml) was hydrogenated over 10% palladium on charcoal catalyst (210 mg) at 50 p.s.i. (3.45 bar). After two and a quarter hours the mixture was filtered through a short arbacel column and evaporated under vacuum. The residue was dissolved in ethyl acetate and acidified with IN hydrogen chloride in diethyl ether. The precipitated salt was filtered and washed with ethyl acetate to give the title amine salt as a white solid (1.88 g, 94%) m.p. 255-6°C (dec). Rf 0.2 (ss-1). Found: C,62.64; H,7.74; N,5.74. C₁₄H₁₉NO₂.HCl requires C,62.33; H,7.47; N,5.19%.

PREPARATION 7

c-3-Amino-c -5-phen ylmethylcycolohexane-r-1-carboxylic acid methyl ester hydrochloride

i. ci s-5-tert -Bu tyldimethylsilyloxy cyclohexane-cis-1,3- dicarboxylic acid dimethyl ester

t-Butyldimethylsilyl chloride (16.58 g, 110 mmole) in dry methylene chloride (65 ml) was added dropwise ever half an hour to a stirred solution of cis-3-hy droxycycloh exane-cis-1,3- dicarboxylic acid dimethyl ester (21.5 g, 99 nmole) [J. Org.

Chem. , 38, 1726 [1973] , triethylcunine (11.13 g, 110 mmole and 4-dimethylamin nopyridine (488 mg, 4 mmole) in methylene chloride (80 ml) , with ice cooling keeping the temperature between 5 and 10º C. After standing overnight at room temperature further amounts of t- bityldimethylsilyl chloride (1.6 g) , triethylamine (1.1 g) and dimethylaminopyridine (450 mg) were added and stirring continued for sixty-eight hours. The mixture was then washed sequentially with water, satxirated aqueous ammonium chloride and water, dried over MgSO₄ and evaporated under vacuum to give a liquid (34.4 g) which was chro matographed on silica gel (600 g) . Elution with a mixture of diethyl ether in hexane (1:3 by volume) gave the required product as a liquid (32.6 g, 99%) Rf 0.3

(1:3 diethyl ether, hexane) . Found: C,57.89; H,9.20. C_{1 6}H₃₀O₅Si requires C,58.15; H,9.15%. ii cis -5-tert-Butyldimethylsilyloxycyclohexane-cis-1,3- dicarboxylic acid mono-methyl ester

IN Sodium hydroxide (94 ml) was added to an ice cooled solution of the above diester (30.87 g, 93.4 mmole) in methanol

(500 ml). The mixture was stirred at 5°C for 3 hours and then allowed to stand at room temperature for eighteen hours. Most of the solvent was evaporated off under vacuum, water was added and the suspension extracted with diethyl ether to recover unreacted diester (3.86 g). The aqueous phase was acidified with 2N hydrochloric acid, extracted with diethyl ether, and the organic extract washed with water, dried over MgSO₄ and evaporated under vacuum to give a clear gum (25.5 g). Chromatography on silica gel

(500 g) eluting with a mixture of diethyl ether in hexane (7:3 by volume) gave the required mono-ester as thick oil (20.0 g, 68%). Rf 0.75 (diethyl ether). Found: C,56.75; H,8.71. C₁₅H₂₈O₅Si requires C,56.93; H,8.92%. iii c-3-teart-Butyldimrethylsilyloxy-c-5-hydroxymethyl-cyclohexane- r-1-carboxylic acid methyl ester

A 1M solution of diborane in tetrahydrofuran (59 ml) was added dropwise under nitrogen to a stirred solution of the mono ester from part ii (17.0 g, 53.72 mmole) in tetrahydrofuran keeping the temperature at -5ºC. The mixture was allowed to warm up to room temperature and after four hours a further amount of lM diborane solution (10.7 ml) was added and the mixture allowed to stand for eighteen hours. The solvent was evaporated under vacuum, diethyl ether was added and the solution washed

sequentially with saturated salt solution, saturated aqueous sodium bicarbonate solution and again with saturated salt

solution. Drying over MgSO₄ and evaporation under vacuum gave a clear oil which was chromatographed on silica gel (500 g).

Elution with a mixture of ethyl acetate and hexane (1:1 by volume) gave an oil (15.18 g, 93%). Rf 0.42 (ss-3). Found: C,59.24;

H,9.67. C₁₅ H₃₀O₄Si requires C,59.56; H,10.0%.

iv. c-3-tert-Butyldimethylsilyloxy-c-5-(4-methylbenzenesulphhonyl- oxymethyl)cyclohexane-r-1-carboxylic acid methyl ester

4-Methyl benzenesulphonyl chloride (14.18 g, 74.39 mmole) was added to an ice cold stirred solution of the ester from part iii (15.0 g, 49.59 mmole) in dry pyridine (130 ml). After stirring at room tenperature for twenty four hours the mixture was poured onto ice, extracted with diethyl ether and the extract washed

sequentially with 2N hydrochloric acid, water, saturated aqueous sodium bicarbonate solution and water. Drying over MgSO₄ and evaporation under vacuum gave an oil (22.0 g) which was

Chromatographed on silica gel (600 g). Elution with increasing proportions of ethyl acetate in hexane (1:9 - 1:4 by volume) gave the required product as an oil (21.78 g, 96%). Rf 0.3 (4:1 hexane, ethyl acetate. Found: C,57.66; H,7.96. C ₂₂H₃₆O₆ SSi requires C,57.86; H,7.95%. v. c- 3-tert -Butyldimethylsilyloxy-c-5-phenylmethyl

cyclohexane-r-1-carboxylic acid methyl ester

2M Phenyl lithium in cyclohexane-ether (7:3) (24.5 ml, 49 mmole) was added under nitrogen to a stirred suspension of cuprous iodide (4.67 g, 24.5 mmole) in dry diethyl ether (50 ml) keeping the temperature belcw 5°C. The resulting dark green solution was stirred at room temperature for one and three quarters of an hour, cooled to -70ºC and a solution of the ester from part iv (3.7 g, 8.1 mmole) in ether (10 ml) and cyclchexane (40 ml) added dropwise. The temperature was maintained below -60°C during the addition, and then reduced to -70°C for fifteen minutes. The mixture was then allowed to warm up to room temperature, stirred for an hour and the reaction quenched with saturated aqueous ammonium chloride with ice cooling. The organic phase was washed with saturated salt solution, dried over MgSO₄ and on evaporation under vacuum gave an oil. Chromatography on silica gel, eluting with increasing proportions of diethyl ether in hexane (1:20 - 1:10 by volume) gave the required title product (1.4 g, 48%) Rf 0.2 (1:9 diethyl ether, hexane).

vi. t-3-(4Methylbenzenesulphonyloxy)-c-3-phenylmethyl

cyclohexane-r-1-carboxylic acid methyl ester

40% Aqueous hydrofluoric acid (0.5 ml, 10 mmole) was added to a stirred solution of the above ester (3.6 g, 9.93 mmole in acetonitrile (40 ml). After an hour the solution was diluted with diethyl ether, washed with saturated aqueous sodium bicarbonate solution and water, dried over MgSO₄ and evaporated under vacuum to give the required alcohol as a clear oil (2.36 g, 96%). Rf 0.2 (1:1 diethyl ether hexane). The product (2.39 g, 9.62 mmole) was treated as described in Preparation 6, part iv to give the

trans-4-methylbenzene sulphonate title compound as a pale yellow gum (2.44 g, 63%). Rf 0.4 (1:1 diethyl ether hexane). Found: C,65.59; H,6.54; C₂₂H₂₆O₅S requires C,65.65; H,6.51%. vii c-3-Amino-c-5-phenylmethylcyclohexane-r-1-carboxylic acid methyl ester hydrochloride

The trans-4-methylbenzenesulphonate from part iv (2.41 g, 5.99 mmole) was treated with sodium azide as described in

Preparation 6, part v to give the corresponding azide as an oil (1.44 g, 88%) , Rf 0.72 (1:1 diethyl ether, hexane). The azide (1.41 g, 5.16 mmole) was then reduced as described in Preparation 6, part vi to give the required amine salt as a foam (1.44 g, 99%), Rf 0.2 (ss-1). Found: C,63.31; H,7.76; N,4.56.

C₁₅H₂₁NO₂.HCl requires C,63.48; H,7.81; N,4.94% PREPARATION 8

cis and trans-3-Amino-c -4-phenylmethylcyclohexane-r-1- carboxylic acid methyl ester hydrochloride

i 3-Oxo-4-phenylmethylenecyclchexanecarboxylic acid methyl ester

A mdxture of ethyl(-trimethylsilyl) acetate (16.01 g,

99.9 mmole) and 3-oxocyclohexanecar boxylic acid methyl ester (13.0 g, 83.24 mmole) was slcwly added dropwise under nitrogen to a stirred solution of 1.0M tetrabutylamm onium fluoride in tetrahydrofuran (2.78ml) keeping the temperature between 0 and 10 C. The resulting pale brown solution was stirred at room tempeaature for seventeen hours, further amounts of

tetrabutylammonium fluoride (0.3 ml) and ethyl(trimethylsilyl) acetate (5 ml) were added and after three hours the reaction was shewn to be completed by n.m.r. The mixture was diluted with n-4ιexane (50 ml), stood over 3A molecular sieves for an hour, filtered and the solvent evaporated under vacuum to give the silylenol ether as a golden oil (19.97 g, 100%). The silylenol ether product in dry methylene chloride (50 ml), was added dropwise under nitrogen to a stirred suspension of titanium tetrachloride (9.15 ml, 83.24 mmole) in benzaldehyde (9.31 ml, 91.56 mmole) and dry methylene chloride (250 ml) at -70°C.

The mixture was allowed to warm up to room temperature over eighteen hours and quenched with water (100 ml) with ice cooling. The organic phase was washed with water, dried over MgSO₄ and evaporated under vacuum. The residue was chromatograpahed on silica gel, eluting with increasing proportions of ethyl acetate in hexane (1:4 - 3:7 by volume) to give the required product as a pale solid (6.89 g, 34%) m.p. 73-5°C. Rf 0.25 (4:1 hexane, ethyl acetate). Found: C,73.20; H,6.54. C₁₅H₁₆ O₃. 0.1H₂O requires C,73.21; H,6.63%. ii. 3-Oxo-cis-4-phenylmethylcyclohexanecarboxylic acid methyl ester

The enone from part i (6.55 g, 26.8 mmole) in methanol (152 ml) and water (8 ml) was hydrogenated over 5% palladium on charcoal catalyst (750 mg) at 20 p.s.i. (1.4 bar). After three hours the suspension was filtered and on evaporation under vacuum the residue was chromatographed on silica gel (600 g). Elution with increasing proportions of ethyl acetate in hexane (1:4 - 3:7 by volume) gave the trans-isomer as a white solid m.p. 54-5°C. Rf 0.35 (1:4 ethyl acetate, hexane). Found: C,73.11; H,7.46.

C₁₅H₁₈O₃ requires C,73.15; H,7.37%. Further elution gave the more polar cis-isomer as a white solid m.p. 71-2°C. Rf 0.25 (1:4 ethyl acetate, hexane). Found: C,72.8l; H,7.41. C_{1 5}H₁₈O requires: C,73.15; H,7.37%. iii. 3-Methoxyiminio-cis-4-phenylmethylcyclohexane carboxylic acid methyl ester

The cis-isomer from part ii above (1.9 g, 7.71 mmole) on treatment with methoxylamine hydrochloride as described in

Preparation 1 part iii gave the title required 0-methyloxime as a clear oil (2.0 g, 94%). Rf 0.4 and 0.45 (4:1 hexane, ethyl acetate). Found: C,69.53; H,7.69; N,4.94. C₁₆H₂₁HO₃ requires C,69.79; H,7.69; N,5.09%. iv. c and t-3-(tert-Butoxycarbonylamdno)-c-4-phenylmethyl cyclohexane-r-1-carboxylic acid methyl ester

The 0-methyl oxime from part iii (1.97 g, 7.15 mmole) on treatment as described in Preparation 1, part iv gave the title product as a mixture of cis and trans-isomers which were separated by chromatography on silica gel (300 g) eluting with increasing proportions of ethyl acetate in hexane (1:3 - 3:7 by volume). The trans-isomer was obtained as a gum (680 mg, 27%). Rf 0.5 (1:4, hexane, ethyl acetate). Found: C,68.84; H,8.17; N,3.91.

C₂₀H₂₉NO₄ requires C,69.14; H,8.41; N,4.03%. The cis-isomer was also obtained as a gum (345 mg, 14%). Rf 0.45 (1:4 hexane, ethyl acetate). Found: C,67.55; H,8.08; H,3.80, C₂₀H₂₉NO₄.0.5 H₂O requires C,67.39; H,8.48; N,3.93%. v. t-3-Amino-c-4-phenyImethylcyclohexane-r -1-carboxylic acid methyl ester hydrochloride

The trans-isomer from part iv (650 mg, 1.87 mmole) on treatment with HCl as described in Preparation 1, part v gave the title salt as a gum (533 mg, 99%). Rf 0.25 (ss-1). Found:

C,62.41; H,7.78; N,4.77. C₁₅H₂₁NO₂. HCl.0.25 H₂O requires C,62.49; H,7.87; N,4.86%. vi. c-3-Amino-c-4-phenylmethylcyclohexane-r-1-carboxylic acid methyl ester hydrochloride

The cis-isomer from part iv (325 mg, 0.94 mmole) on treatment with HCl as described in Preparation 1, part v, gave the title salt as a gum (263 mg, 99%). Rf 0.25 (ss-1). Found: C,59.45; H,7.44; N,4.77. C₁₅H₂₁NO₂. HCl. H₂O requires C,59.69; H,8.01; N,4.64% EXAMPLE 1

3-{1-[(cis-4-Ethoxycarbonyl-cis-3-{2-phenylethyl}cyclohexyl)- carbamoyl]cyclopentyl}-2-(2-methoxyethyl)prooanoic acid benzyl ester

1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride

(460 mg, 2.4 mmole) was added to an ice cold stirred solution of 3-(1-carboxycyclopentyl)-2-(2-methyoxyethyl)propanoic acid benzyl ester (EP-A-0274234) (401 mg, 1.2 mmole), c-4-amdno-c-2-(2- phenylethyl)cyclohexane-r-1-carboxylic acid ethyl ester

hydrochloride (343 mg, 1.1 mmole), 1-hydroxybenzotriazole (162 mg, 1.2 mmole) and N-methyl-morpholine (354 mg, 3.5 mmole) in dry methylene chloride (15 ml). After half an hour the mixture was allowed to attain room temperature and stirred for twenty hours. The solvent was evaporated under vacuum and the residue

partitioned between diethyl ether and water. The organic extract was washed sequentially with water, 2N hydrochloric acid, water, saturated aqueous sodium bicarbonate and water. Drying (MgSO₄) and evaporation under vacuum gave an oil (640 mg) , which was chromatographed on silica gel (50 g) eluting with a mixture of diethyl ether and hexane (7:3 by volume) to give the required diester as a colourless oil (550 mg, 85%). Rf 0.32 (7:3 diethyl ether, hexane). Found: C,73.23; H,8.37; N,2.12. C₃₆H₄₉NO₆ requires C,73.07; H,8.35; N,2.37%. EXAMPLES 2-5

The following compounds were prepared following the piocsdure of Example 1 using the appropriate amine of formula (IV) .

EXAMPLES 6-7

The following compounds were prepared following the proc edure of Example 1 but using 3-(1-carboxycyclopentyl)-2 (S)-(2-methoxy- ethoxymethyl)proparιoic acid t-butyl ester (EP application no. 89304698.7) as the starting material and coupling with the appropriate amine of formula (IV) .

EXAMPL ES 8-12

The following compounds were prepared following the procedure of Example 1 but using 2S-(N²-benzyloxycarbonyl-N⁶-t-butyloxy- catbonyl-S-lysylaminomethyl)-3-[1-(1-carboxycyclopentyl)]propanoic acid t-butyl ester (EP application 89305180) as the starting material and coupling with the appropriate amine of formula (IV).

EXAMPLE 13

2(S)-(N⁶ -t-Butoxycarbonyl-S-lysyl-aminomethyl)-3-{1-[cis-4 ethoxycarbonyl-cis-3-{3-ethoxypropyl}cyclchexyl)carbamoyl] cyclopentyl}propanoic acid t-butyl ester

The diester of Example 8 (734 mg, 0.85 mmole) in methanol (18 ml) and water (2 ml) was hydrogenated at room temperature for three hours over 5% palladium on charcoal catalyst (75 mg) at 50 p.s.i. (3.45 bar) pressure. The suspension was filtered tihrcugh arbacel, and evaporation of the solvent under reduced pressure gave the title product as a white foam (630 mg, 100%). Rf 0.66 (ss-1). Found: C,63.22; H,9.73; H,7.17. C₃₈H₁₀N₄O₉ requires C,62.78; H,9.70; 7.71%.

EXAMPLES 14-17

The following compounds were prepared from Examples 9-12 by hydrogenation following the piocedure of Example 13.

EXAMPLE 18

2S-(N²-Methanesulphonyl-N⁶-t-butoxycarboryl-S-lysyl-aminomethyl)-3-{1-[(cis-4-ethoxycarbonyl-cis-3-{3-ethoxypropyl}cyclohexyl)carbamoyl]cyclopentyl}propanoic acid t-butyl ester

Methanesulphonyl chloride (0.14 ml, 1.8 mmole) was added dropwise to an ice cold stirred solution of the amine from Example 13 (601 mg; 0.83 mmole) and N-methyilmorpholine (0.2 ml, 1.8 mmole) in dry methylene chloride (8 ml). The solution was stirred at 10ºC for 3 hours and the reaction mixture then quenched with saturated aqueous sodium hydrogencarbonate. The organic phase was separated, the aqueous phase extracted with methelene chloride and the combined extracts dried over MgSO₄. Evaporation under vacuum gave a gum which was chromatographed on silica gel (100 g) eluting with increasing proportions of ethyl acetate in hexane starting with a 1:1 mixture and finally with neat ethyl acetate.

Evaporation of relevant fractions gave the required product as a foam (576 mg, 87%). Rf 0.56 (ss-1). Found: C,58.66; H,8.91; N,6.65. C₃₉H₇₂N₄O₁₁S requires C,58.18; H,9.01; N,6.96%.

EXAMPLES 19-23

The following compounds were prepared in a similar manner to Example 18, using the appropriate amine of Examples 14 to 17 and reacting with the appropriate sulphonyl chloride or acyl chloride to yield the N²-substituted-lysyl derivative.

o

EXAMPLE 24

2S-{bis-(1S)-Phenylethyl]aminomethyl}-3-{1-[cis-4-ethoxy- carbonyl-cis-3-(3-methoxypropyl)cyclohexyl)carbamoyl] cyclopentyl}- propanoic acid t-butyl ester

2S-{bis-[1S)-Pherylethyl]aminomethyl}-3-(1-carboxy- cyclope n tyl)propanoic acid and c-4-amino -c -2-(3-methoxypropyl)- cyclohexane-r-1-carboxylic acid ethyl ester (from Preparation 2) were coupled as described in Example 1 to give the title diester as a gum. Rf 0.1 (4:1 hexane, ethyl acetate) Found: C,73.19;

H,9.13; N,4.01. C₄₃H₆₄N₂O₆ requires C,73.26; H,9.15; N,3.97%.

EXAMPLE 25

2S-{bis[ (1S)-Phenylethyl]amin omethyl}-3-{1[ (cis-4-ethoxy- carbonyl-cis-3-(2- phenylethyl)cyclohexyl)carbamoyl]cyclopentyl}- propanoic acid t-butyl ester

The title compound was prepared as described in Example 24 above using c -4-amdno-c -2-(2-pherylethyl)cyc lo hexane-r-1- carboxylic acid ethyl ester hydrochloride (from Preparation 1) as the amine component to yield the product as a white foam. Rf 0.55 (ss-3) . Found: C,76.11; H,8.74; N,4.25. C₄₇H₆₄N₂O₅, 0.25H₂O requires C,76.12; H,8.77; N,3.77%. EXAMPLE 26

2S-(Amdnomethyl)-3-{1-[(cis-4-ethoxycarbonyl-cis-3-{3-methoxy- propyl}cyclohoexyl)carbanoyl]cyclopentyl}propanoic acid t-butyl ester

The diester from Example 24 above (992 mg, 1.4 mmole) in ethanol (20 ml) was hydrogenated over 20% palladium hydroxide on charcoal catalyst at 60 p.s.i. (4.1 bar) pressure. After twenty four hours the suspension was filtered through a short arbacel column and the solvent was evaporated under vacuum. The residue was dried azeotropically with methylene chloride to give the title amine as a thick oil. (690 mg, 99%) Rf 0.35 (ss-1) Found:

C,65.69 H,9.88; N,5.19. C₂₇H₄₈N₂O₆ requires C,65.29; H,9.74; N,5.64%.

EXAMPLE 27

2S-(Aminomethyl)-3-{1-[(cis-4-ethoxycarbonyl-cis-3-(2-phenylethyl)cyclohexyl)carbamoyl]cyclopentyl}propanoic acid t-butyl ester

The product of Example 25 was hydrogenated as described in Example 26 above to yield the title compound as a gum. Rf 0.35 (ss-1) Found: C,69.00; H,8.80; N,4.88. C₃₁H₄₈N₂O₅. 0.6 H₂O requires C,69.00; H,9.19; N,5.19. EXAMPLE 28

2S-(N²-Methanesulphonyl-N⁶-t-butoxycarbonyl-S-lysyl-aminomethyl) 3-{1-[ (cis-4-ethoxycarbonyl-cis-3-{3-methoxypropyl}cyclohexyl)carbamoyl]cy clopentyl}propanoic acid t-butyl ester

N-methylmorpholine (0.34 ml, 3.06 mmole) was added to an ice cooled stirred mixture of the product from Example 26 (690 mg, 1.39 mmole) N² -methanesulphonamido- N⁶-t-butoxycarb onyl-S-lysin e (406 mg, 1.39 mmole) , 1-hydroxybenzotxiazole (188 mg, 1.39mmole) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride

(586 mg, 3.06 mmole) in dry methylene chloride (10 ml) . After six hours the mixture was diluted with methylene chloride (20 ml) washed with water and dried over MgSO ₄. Evaporation of the solvent under vacuum and c hromatography on silica gel, eluting with increasing proportions of ethyl acetate in hexane (50 - 90%) and finally with 5% ethanol in ethyl acetate gave the required product as a cream foam (880 mg, 81%) . Rf 0.2 (ss-3) Found:

C,58.07; H,9.06; N,6.74. C₃₉H₇₀N₄O_{1 1}S requires C,58.33; H,8.79; N,6.98%.

EXAMPLE 29

2S-(N-t-Butyloxycarbonyl-R-alanylaminomethyl)-3-{1-[(cis-4- ethoxycarbonyl-cis-3-(2-phenylethyl)cyclohexyl)carbamoyl]cyclopentyl}propanoic acid t-butyl ester

The procedure of Example 28 was followed starting with the amine of Example 27 and coupling with N-t-butyloxycarbonyl-R- alanine to yield the title product as a foam. Rf 0.5 (ss-1).

Found: C,67.22; H,8.86; N,5.66. C₃₉H₆₁N₃O₈ requires C,66.92;

H,8.78; N,6.00%.

EXAMPLE 30

2-[N-(2-t-Butyloxycarbonylamdno-2-m ethylpropanoyl) amdnomethyl]-3-{1-[ (cis-4-ethoxycarbonyl-cis-3-(2-phenylethyl)cyclohexyl)carbamoyl]cyclop entyl}propanoic acid t-butyl ester

The procedure of Example 28 was followed starting with the amine of Example 27 and coupling with 2-t-butyloxycarbonyl amino-

2-methyl-propanoic acid to give the title product as a foam. Rf

0.48 (ss-1) . Found: C,67.06; H,8.94; N,5.81. C₄₀H₆₃N₃O₆ requires

C,67.29; H,8.89; N,5.89%

EXAMPLE 31

2S-(N²-Methanesulphonyl-S-lysyl-aminomethyl)-3-{1-[(cis-4- carboxy-cis-3-{2-phenylethyl}cyclohexyl)carbamoyl]cyclopentyl}- propanoic acid

Trifluoroacetic acid (5 ml) was added to an ice cold solution of 2S-(N²-methanesulphonyl-N⁶-t-butoxycarbonyl-S-lysyl-amino- methyl)-3-{1-[(cis-4-ethoxycarboιyl-cis-3-(2-phenylethyl)cycle- hexyl)carbamoyl]cyclopenyl}propanoic acid-t-butyl ester (from Example 19) (445 mg, 0.53 mmole) in dry methylene chloride (5 ml). The solution was allowed to warm to room temperature and after three hours evaporated to dryness under vacuum. The residue was dried azeotrcpically twice with toluene and dissolved in IN sodium hydroxide, the solution was stirred at 40-55°C for sixty eight hours, cooled and passed dcwn a sulphonic acid ion-exchange column. Elution with 10% aqueous pyridine and evaporation of the relevant fractions gave a foam which was crushed under

acetonitrile and filtered to give a white powder (279 mg, 80%) Rf 0.25 (ss-2) Found: C,58.66; H,7.92; N,8.49. C₃₂H₅₀N₄O₈S requires: C,59.06; H,7.74; N,8.61%.

EXAMPLES 32-37

The following compounds were prepared from the appropriate N⁶-t-butyloxycarbonyl protected diester of Examples 18, 20-23 or 28 by treatment with trifluoroacetic acid followed by alkaline hydrolysis following the procedure of Example 31.

EXAMPLES 38-39

The following compounds were prepared from the diesters of Examples 29 and 30 by treatment with trifluoroacetic acid followed by alkaline hydrolysis following the procedure of Example 31.

EXAMPLE 40

3-{1-[cis-4-Carboxy-cis-3-{2-phenylethyl}cycloexyl)- carbamoyl]cyclopentyl}-2-(2-methoxyethyl)propanoic acid

The diester of Example 1 (510 mg, 0.86 mmole) in ethanol (25 ml) and water (10 ml) was hydrogenated at room temperature for three hours over 10% palladium on charcoal catalyst (100 mg) at 50 p.s.i. (3.45 bar) pressure. The mixture was filtered through a short Avicel column and the solvent evaporated under reduced pressure. The monoester thus obtained was dissolved in IN sodium hydroxide and the solution heated to 65°C under a nitrogen atmosphere for two days. On cooling the solution was extracted with diethyl ether, the aqueous phase acidified with 2N

hydrochloric acid and extracted with diethyl ether. The organic phase was washed with water, dried over MgSO₄ and evaporated under reduced pressure to give the required title diacid as a white foam, (300 mg, 75%). Rf 0.62 (ss-1) Found: C,68.17; H,8.45;

N,2.95. C₂₇H₃₉NO₆ requires C,68.47; H,8.30; N,2.96%.

EXAMPLES 41-44

The following compounds were prepared from the appropriate diester of Examples 2 to 5 by hydrogenation followed by alkaline hydrolysis following the procedure of Example 40.

EXAMPLE 45

2S-(2-Methoxyethoxymethyl)-3{1-[(cis-4-carboxy-cis-3-{3-methoxy- propyl}cyclohesxy)carb amoyl]cyclopentyl}propanoic acid

Trifluoroacetic acid (5 ml) was added to an ice cold solution of the diester of Example 6 (480 mg; 0.77 mmole) in dry methylene chloride (3 ml). After standing at room temperature for three hours the solution was evaporated to dryness under vacuum and the residue was dried azeotropically with toluene. The residual oil was dissolved in diethyl ether, washed with water (x9) and the resulting mono-ester extracted into IN sodium hydroxide solution (2 x 10 ml). The aqueous extract was heated at 65-70°C under nitrogen for 24 hours, cooled saturated with salt, acidified with concentrated hydrochloric acid and extracted with ethyl acetate. The organic extract was washed with water, dried over MgSO₄ and on evaporation gave the required diacid as a gum (320 mg 88%).

Found: C,60.55; H,8.54; N,2.80, C₂₄H₄₁ NO _8. 0.4H₂O requ ires C,60.20; H,8.80; N,2.93%.

EXAMPLE 46

2S-(2-Methoxyethoxymethyl)-3-{1-[(cis-4-carboxy-cis-3-{3-ethoxy- propyl}cylohexyl)carbamoyl]cyclopentyl}propanoic acid

The title product was prepared from the diester of Example 7 as described in Example 45 above and was obtained as a gum.

Found: C,61.26; H,8.66; N,2.83. C₂₅H₄₃NO₈. 0.3H₂O requires C,61.15; H,8.95; N,2.85%

Claims

1. A compound having the formula: -

wherein A completes a 4 to 7 membered carbocyclic ring which may be saturated or mono-unsaturated and which may optionally be fused to a further saturated or

-msaturated 5 or 6 membered carbocyclic ring;

B is (CH₂)_m wherein m is an integer of from 1 to 3; each of R and R⁴ is independently H, C₁-C₆ alkyl, benzyl or an alternative biolabile ester-forming group;

R¹ is H or C₁-C₄ alkyl;

R² is C₁-C₆ alkyl substituted by C₁-C₄ alkoxy, aryl or aryloxy;

and R⁵ is C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇ cycloalkyl, or C₃-C₇ cycloalkenyl,

or R⁵ is C₁-C₆ alkyl substituted by halo, hydroxy, C₁-C₆ alkoxy, C₁-C₆ alkoxy(C₁-C₆)alkoxy, C₃-C₇ cycloalkyl, C₃-C₇ cycloalkenyl, aryl, aryloxy, heterocyclyl, -NR⁶R⁷,

-NR⁸COR⁹, -NR⁸SO₂R¹⁰, -CONR⁶R⁷ or R⁶R⁷N-(C₁-C₆)alkoxy; or R⁵ is C₁-C₆ alkyl substituted by a group of the formula:

wherein R⁶ and R⁷ are each independently H, C₁-C₄ alkyl, C₃-C₇ cycloalkyl, aryl, aryl(C₁-C₄)alkyl, C₂-C₆ alkoxyalkyl, or heterocyclyl; or the two groups R⁶ and R⁷ are taken together with the nitrogen to which they are attached to form a pyrrolidinyl, piperidino, morpholino, piperazinyl or N-(C₁-C₄)alkyl-piperazinyl group;

R⁸ is H or C₁-C₄ alkyl;

R⁹ is C₁-C₄ alkyl, CF₃, aryl, aryl(C₁-C₄) alkyl, aryl(C₁-C₄) alkoxy, heterocyclyl, C₁-C₄ alkoxy or NR⁶R⁷ wherein R⁶ and R⁷ are as previously defined;

R¹⁰ is C₁-C₄ alkyl, C₃-C₇ cycloalkyl, aryl or heterocyclyl;

R¹¹ is H, C₁-C₆ alkyl, aryl or C₃-C₇ cycloalkyl;

R¹² is R¹¹CONR¹¹-, R¹¹SO₂NR¹¹-, R¹⁶R^l7N-(CH₂)_p-, or R¹¹O-, wherein each R¹¹ is as previously defined above; R¹³ andR¹⁴ are each independently H or C₁-C₆ alkyl; or R¹³ is H and R is C₁-C₆ alkyl which is substituted by

OH, C₁-C₄ alkoxy, SH, SCH₃, NIL, aryl(C₁-C₆)alkyl-

OCONH-, NE₂CO-, CO₂H, guanidino, aryl, or heterocyclyl; or the two groups R¹³ and R¹⁴ are joined together to form, with the carbon atom to which they are attached, a

5 or 6 membered carbocyclic ring which may be saturated or monc)-unsaturated and which may optionally be substituted by C₁-C₄ alkyl or fused to a further 5 or 6 membered saturated or unsaturated carbocyclic ring; or R¹³ is H, and R¹² and R¹⁴ are linked to form a

2-(N-COR¹¹-4-aminopyrrolidinyl) group;

R¹⁵ is R¹⁶R¹⁷NCO-, R¹¹OCO-, R^{1 1}OCH₂- or heterocyclyl, wherein R¹¹ is as previously defined above; R¹⁶ and R¹⁷ are each independently H or C₁-C₆ alkyl; and p is 0 or an integer of from 1 to 6;

and pharmaceutically acceptable salts thereof and bioprecursors therefor.

2. A compound according to claim 1 wherein A is (CH₂)₄, R¹ is H and B is (CH₂)₂ having the formula- :

wherein R, R², R⁴ and R⁵ are as previously defined.

3. A compound as claimed in claim 1 or claim 2 wherein R and R⁴ are both H.

4. A compound as claimed in claim 1 or claim 2 wherein one or both of R and R⁴ is a biolabile ester-forming group and said group is ethyl, benzyl, 1-(2,2-diethylbutyryloxy)ethyl, 2-ethyl- propionyloxymethyl, 1-(2-ethylpropionyloxy)ethyl, 1-(2,4-dimethyl- benzoyloxy)ethyl, 1- (benzoyloxy)benzyl, 1-(benzoyloxy)ethyl, 2-methyl-1-propioryloxypropyl, 2,4,6-trimethylbenzoyloxymethyl, 1-(2,4,6-trimethylbenzyloxy)ethyl, pivalcyloxymethyl, phenethyl, pherpropyl, 2,2,2-trifluoroethyl, 1- or 2-naphthyl,

2,4-dimethylphenyl, 4-t-butylpheryl, [5-(4-methyl-1,3-dioxolen-

2-onyl)]methyl or 5-indanyl.

5. A compound according to any one of claims 1 to 4 wherein R⁵ is methylene su bstituted by a group of the formula

-MHCOCR¹²R¹³ R¹⁴, where R¹² is NE₂, R¹¹CONH- or R¹¹SO₂NH-, R ¹³ is H and R¹⁴ is -(CH₂)₄NH ₂.

6. A compound according to claim 5 wherein R⁵ is N²-acetyl-S- lysylamimomethyl, N²-methanes ulphonyl-S-lysyl-aminomethyl,

N²-phenylsul phonyl-S-lysyl-aminomethyl or N²-cyclobutylcarbonyl-S- lysyl-aminomethyl.

7. A compound according to any one of claims 1 to 4 wherein R⁵ is methoxyethyl or 2-methoxyethoxymethyl.

8. A compound according to any one of claims 1 to 4 wherein R⁵ is C₁-C₆ alkyl substituted by -NHCOCR¹²R¹³R¹⁴ wherein R¹² is N H₂ , R¹³ is CH₃ and R¹⁴ is H or CH₃.

9. A compound according to any one of claims 1 to 8 wherein R² is phenyl, benzyl, phenethyl, methoxypropyl or ethoxypropyl.

10. A compound according to claim 1 wherein said compound is

2S-(N²-methanes ulphonyl-S-ly sylamdnomethyl) -3-{1-[cis-4- carboxy-3-cis{3-ethoxypropyl}-cyclohexyl)carbamoyl]cyclopentyl}- propanoic acid;

2-(N²-methanesulphonyl-S-lysylamdnomethyl)-3-{1-[ (cis-4- carboxy-3-cis-phenet hyl-cyclohexyl)carbamoyl]cyclopentyl}propanoic acid;

2S-(2-methoxyetiιoxymethyl)-3-{1-[ (cis-4-carboxy-3-cis-{3- ethoxyproρyl}cyclohe xyl)c arbamoyl]cyclopentyl}propanoic acid or

2S-(2-methoxyethoxymethyl)-3-{1-[ (cis-4-carboxy-3-cis-{3- methoxypropyl}-cyclohexyl)carbamoyl]cyclopentyl}propanoic acid, or a biolabile ester derivative thereof.

11. A process for preparing a compound of the formula (I) as claimed in claim 1 which comprises subjecting a compound of the formula-:

wherein R¹⁸ andR¹⁹ are as defined for R and R⁴ excluding H, or they are conventional carboxylic acid protecting groups and R^5' is as defined for R⁵ with any reactive groups therein optionally protected;

to a hydrolysis and/or hydrogenation and/or other deprotection reaction to remove any protective group present in R^5' and to remove one or both of R¹⁸ and R¹⁹ to yield the corresponding dicarboxylic acid of formula (I) wherein R and R⁴ are both H, or to yield the corresponding mono-ester product wherein one of R and R⁴ is H and the other is a biolabile ester-forming group; and optionally forming a pharmaceutically acceptable salt of the product.

12. A process as claimed in claim 11 wherein R¹⁸ and R¹⁹ are selected from t-butyl, ethyl and benzyl and said groups are removed by treatment with trifluoroacetic acid, aqueous alkali or catalytic hydrogenation respectively, to yield the compound of formula (I) wherein R and R⁴ are both H.

13. A pharmaceutical composition comprising a compound of the formula (I) or (II) as claimed in any one claims 1 to 10 or a pharmaceutically acceptable salt thereof or bioprecursor therefor, together with a pharmaceutically acceptable diluent or carrier.

14. A compound of the formula (I) or (II) as claimed in any of claims 1 to 10 or a pharmaceutically acceptable salt thereof or bioprecursor therefor, for use in medicine, particularly for the treatment of hypertension, heart failure or renal insufficiency.

15. A process for preparing a compound having the formula-:

wherein A completes a 4 to 7 membered carbocyclic ring which may be saturated or mono-unsaturated and which may optionally be fused to a further saturated or unsaturated 5 or 6 membered carbocyclic ring;

B is (CH₂)_m wherein m is an integer of from 1 to 3; each of R and R⁴ is independently H, C₁-C₆ alkyl, benzyl or an alternative biolabile ester-forming group;

R¹ is H or C₁-C₆ alkyl; R² is C₁-C₆ alkyl substituted by C₁-C₄ alkoxy, aryl or aryloxy;

and R⁵ isC₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇ cycloalkyl, or C₃-C₇ cycloalkenyl,

or R⁵ is C₁-C₆ alkyl substituted by halo, hydroxy, C₁-C₆ alkoxy, C₁-C₆ alkoxy(C₁-C₆)alkoxy, C₃-C₇ cycloalkyl, C₃-C₇ cycloalkenyl, aryl, aryloxy, heterocyclyl, -NR⁶R⁷,

-NR⁸COR⁹, -NR⁸SO₂R¹⁰, -CONR⁶R⁷ or R⁶R⁷N-(C₁-C₆) alkoxy; or R⁵ is C₁-C₆ alkyl substituted by a group of the formula:

wherein R⁶ and R⁷ are each independently H, C₁-C₄ alkyl, C₃-C₇ cycloalkyl, aryl, aryl(C₁-C₄)alkyl, C₂-C₆ alkoxyalkyl, or heterocyclyl; or the two groups R⁶ and R⁷ are taken together with the nitrogen to which they are attached to form a pyrrolidinyl, piperidino, morpholino, piperazinyl or N-(C₁-C₄)alkyl-piperazinyl group;

R⁸ is H or C₁-C₄ alkyl;

R⁹ is C₁-C₄ alkyl, CF₃, aryl, aryl(C₁-C₄)alkyl, aryl(C₁-C₄)alkoxy, heterocyclyl, C₁-C₄ alkoxy or NR⁶R⁷ wherein R⁶ and R⁷ are as previously defined; R¹⁰ is C₁-C₄ alkyl, C₃-C₇ cycloalkyl, aryl or heterocyclyl;

R¹¹ is H, C₁-C₆ alkyl, aryl or C₃-C₇ cycloalkyl;

R¹² is R¹¹CONR¹¹-, R¹¹SO₂NR¹¹-, R¹⁶R¹⁷N-(CH₂)_p-, or R¹⁴0-, wherein each R¹¹ is as previously defined above; R¹³ and R¹⁴ are each independently H or C₁-C₆ alkyl; or R¹³ is H and R¹⁴ is C₁-C₆ alkyl which is substituted by

OH, C₁-C₄ alkoxy, SH, SCH₃, NH₂, aryl(C₁-C₆)alkyl-

OCONH-, NH₂CO-, CO₂H, guanidino, aryl, or heterocyclyl; or the two groups R¹³ and R¹⁴ are joined together to form, with the carbon atom to which they are attached, a

5 or 6 membered carbocyclic ring which may be saturated or moro-unsatαirated and which may optionally be substituted by C₁-C₄ alkyl or fused to a further 5 or 6 membered saturated or unsaturated carbocyclic ring;

or R¹³ is H, and R¹² and R¹⁴ are linked to form a

2-(N-COR¹¹-4-aminopyrrolidinyl) group;

R¹⁵ is R¹⁶R¹⁷NCO-, R¹⁷OCO-, R¹¹OCH₂- or heterocyclyl, wherein R¹¹ is as previously defined above;

R¹⁶ and R¹⁷ are each independently H or C₁ -C₆ alkyl; and p is 0 or an integer of from 1 to 6;

which comprises subjecting a compound of the formula

wherein R¹⁸ and R¹⁹ are as defined for R and R⁴ excluding H, or they are conventional carboxylic acid protecting groups and R^5' is as defined for R⁵ with any reactive groups therein optionally protected;

to a hydrolysis and/or hydrogenation and/or other deprotection reaction to remove any protective group present in R^5' and to remove one or both of R¹⁸ and R¹⁹ to yield the corresponding dicarboxylic acid of formula (I) wherein R and R⁴ are both H, or to yield the corresponding mono-ester product wherein one of R and R⁴ is H and the other is a biolabile ester-forming group; and optionally forming a pharmaceutically acceptable salt of the product.

16. A process as claimed in claim 15 wherein R¹⁸ and R¹⁹ are selected from t-butyl, ethyl and benzyl and said groups are removed by treatment with trifluoroacetic acid, aqueous alkali or catalytic hydrogenation respectively, to yield the compound of formula (l ) wherein R and R⁵ are both H.

17. A process according to claiml5 wherein A is (CH₂)₄, R¹ is H and B is (CH₂)₂ to give a compound having the formula-:

wherein R, R², R⁴ and R⁵ are as previously defined.

18. A process according to claim 15 wherein R⁵ is N²-acetyl-S- lysylamin omethyl, N²-methanesulphonyl-S-lysylaminom ethyl, N²- phenylsulphonyl-S-lysylamin omethyl or N²-cyclobutylcarbonyl-S- lysylaminomethyl.

19. A process according to claim 15 wherein R⁵ is methoxyethyl or

2-methoxyethoxymethyl.

20. A process according to claim 15 wherein R⁵ is C₁-C₆ alkyl substituted by -NHCOCR¹²R¹³R¹⁴ wherein R¹² is NH₂, R¹³ is CH₃ and

R¹⁴ is H or CH₃.

21. A process according to claim 15 wherein R⁵ is phenyl, benzyl, phenethyl, methoxypropyl or ethoxypropyl.

22. A process according to claim 15 wherein said compound of formula (I) produced is-:

2S- (N²-methanesuldphonyl-S-lysylaminomethyl) -3-{1-[cis-4- carboxy-3-cis{3-ethoxypropyl}-cycldhexyl)carbamoyl]cyclopentyl}- propanoic acid;

2-(N²-m ethane sulphonyl-S-lysylamin omethyl)-3-{1-[ (cis-4- car boxy-3-ci s-phenethyl-cyclohexyl)carbamoyl]cyclopentyl}propanoic acid;

2S-(2-methoxyethoxymethyl)-3-{1-[ (cis-4-carboxy-3-cis-{3- ethox ypropyl}cyclohexyl)carbamoyl]cyclope ntyl}propanoic acid or

2S-(2-methoxyethoxymethyl)-3-{1-[ (cis-4-carboxy-3-cis-{3- methoxypropyl}-cyclchex yl)carbamoyl] cyclopentyl}propanoic acid, or a biolabile ester derivative thereof.