Abstract: Compounds of the formula ##STR1## are inhibitors of 5.alpha.-reductase and are useful alone or in combination with other active agents for the treatment of hyperandrogenic disorders such as acne vulgaris, seborrhea, female hirsutism, male pattern baldness, and benign prostatic hyperplasia.

Abstract: Novel derivatives of LSD having the formula ##STR1## wherein R.sub.1 is an alkyl, cycloalkyl or aryl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 carbon atom;R.sub.2 is a bond or ##STR2## wherein R.sub.3 is alkyl, cycloalkyl or aryl group having 2 to 10 carbon atoms, preferably an alkyl group having 2 or 5 carbon atoms; Z is an immunogenic carrier substance, an enzyme donor polypeptide or a label selected from the group consisting of an enzyme, a substance having fluorescent or luminescent properties and a radioactive substance; and n is 1 to p where p equals MW of Z/1000. The derivatives include maleimide conjugates of an immunogenic poly(amino acid), an enzyme donor polypeptide or a labeling substance such as an enzyme, a fluorescent substance or a radioactive substance. Novel activated hapten intermediates useful in the preparation of the conjugates and methods for synthesis of the hapten intermediates and their conjugate derivatives are also disclosed.

Abstract: Compounds of formula (I) wherein: the dotted line indicates that a double bond may be present or absent; R.sup.1 is H, methyl or ethyl; R.sup.2 is .alpha.- or .beta.-C.sub.1-10 straight or branched alkyl; R.sup.3 is CO.sub.2 H, CN, CO.sub.2 R.sup.4, COHNR.sup.4, or CON(R.sup.4).sub.2 ; R.sup.4 is H, C.sub.1-10 straight or branched alky, aryl, heteroaryl, or aralkyl; Aryl is phenyl, substituted phenyl, naphthyl, or biphenyl; Heteroaryl is pyridil, pyrrolyl, thienyl, furanyl or quinolinyl; and Aralkyl is C.sub.1-10 alkyl substituted with one to three phenyl or substituted phenyl moieties; and their pharmaceutically acceptable salts are described. These compounds are 5.alpha.-reductase type 1 inhibitors. They may be used for treating conditions associated with an excess of DHT, either alone or in combination with other 5.alpha.-reductase inhibitors.

Abstract: The present invention relates to compounds of formula (I), wherein carbons 1 and 2 are joined by either a single or a double bond; R.sup.1 is hydrogen or methyl; R.sup.2 is hydrogen or methyl; R.sup.3 is (A) or (B) wherein X, W, Z, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are various groups, and pharmaceutically acceptable solvates thereof and their use in the treatment of androgen responsive and mediated diseases.

Abstract: The novel compounds of the present invention are those of structural formula I: ##STR1## or a pharmaceutically acceptable salt, or stereoisomer thereof, which are inhibitors of 5.alpha.-reductase, particularly 5.alpha.-reductase type 1. The compounds of formula I are useful in the systemic, including oral, or parenteral or topical treatment of hyperandrogenic conditions such as acne vulgaris, seborrhea, androgenic alopecia which includes female and male pattern baldness, female hirsutism, benign prostafic hyperplasia, and the prevention and treatment of prostatic carcinoma, as well as in the treatment of prostatitis. Methods of using the compounds of formula I for the treatment of hyperandrogenic conditions such as acne vulgaris, seborrhea, androgenic alopecia, male pattern baldness, female hirsutism, benign prostatic hyperplasia, and the prevention and treatment of prostatic carcinoma, as well as the treatment of prostatitis are provided, as well as pharmaceutical compositions for the compounds of formula I.

Abstract: Described are new delta-17 and delta-20 olefic and saturated 17.beta.-substituted 4-aza-5.alpha.-androstan-3-ones and related compounds and the use of such compounds as 5.alpha.-reductase inhibitors for treatment of benign prostatic hyperplasia and other hyperandrogenic related disorders.

Abstract: Compounds of formula (I) are inhibitors of the 5.alpha.-reductase 1 isozyme, and are useful alone, or in combination with a 5.alpha.-reductase 2 inhibitor, for the treatment of androgenic sensitive disorders such as acne vulgaris, seborrhea, female hirsutism, male pattern baldness, and benign prostatic hyperplasia.

Abstract: Compounds of the Formula I ##STR1## are inhibitors of the 5.alpha.-reductase 1 isozyme, and are useful alone, or in combination with a 5.alpha.-reductase 2 inhibitor, for the treatment of androgenic sensitive disorders such as acne vulgaris, seborrhea, female hirsutism, male pattern baldness, and benign prostatic hyperplasia.

Abstract: The present invention provides compounds of formula (D wherein the symbol - - - represents a single or a double bond; R is a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group; A is a single bond or a straight or branched C.sub.1 -C.sub.6 alkylene chain; B is a straight or branched C.sub.1 -C.sub.12 alkylene group optionally substituted by one or more aryl groups or fluorine atoms; W is a group R.sub.1 or (a) wherein R.sub.1 is a straight or branched C.sub. -C.sub.6 alkyl group unsubstituted or substituted by one or more fluorine atoms, provided that at least a fluorine atom is present in B or W. The compounds of the invention are useful as testosterone 5.alpha.-reductase inhibitors.

Abstract: Described are new 7.beta.-substituted 4-aza-5.alpha.-androstan-3-ones and related compounds as 5.alpha.-reductase inhibitors.

Abstract: The novel process of this invention involves the reduction of certain .DELTA.-5 steroidal alkenes to selectively produce either the 5.alpha. or 5.beta. reduction products. Particularly, this invention involves reduction of .DELTA.-5 steroidal alkenes using a rhodium based catalyst in the presence of hydrogen to selectively yield 5.alpha. steroids or alternatively reduction of .DELTA.-5 steroidal alkenes in an ionizing medium with a trialkylsilane to selectively yield 5.beta. steroids.

Abstract: Described are new 16-substituted and 7,16-disubstituted 4-aza-5.alpha.-androstan-3-ones and related compounds as 5.alpha.-reductase inhibitors.

Abstract: Non-steroidal compounds which are high affinity, high selectivity modulators for steroid receptors are disclosed. Also disclosed are pharmaceutical compositions incorporating such compounds, methods for employing the disclosed compounds and compositions for treating patients requiring steroid receptor agonist or antagonist therapy, intermediates useful in the preparation of the compounds and processes for the preparation of the steroid receptor modulator compounds.

Abstract: Described are new 17.beta.-carboxanilides of 4-aza-5.alpha.-androstan-3-ones and related compounds of structural formula I: ##STR1## and the use of such compounds as 5.alpha.-reductase inhibitors for treatment of benign prostatic hyperplasia acne, seborrhea, female hirsutism, prostatitis, and prostatic carcinoma and other hyperandrogenetic related disorders.

Abstract: Non-steroidal compounds which are high affinity, high selectivity modulators for steroid receptors are disclosed. Also disclosed are pharmaceutical compositions incorporating such compounds, methods for employing the disclosed compounds and compositions for treating patients requiring steroid receptor agonist or antagonist therapy, intermediates useful in the preparation of the compounds and processes for the preparation of the steroid receptor modulator compounds.

Abstract: The present invention relates to a process for the preparation of finasteride, the compound of formula (I), comprising the reaction of the compound of formula (II) with t-butylamine.

Abstract: Derivatives of benzo[5,6]cyclohepta pyridine, and pharmaceutically acceptable salts and solvates thereof are disclosed, which possess anti-allergic and anti-inflammatory activity. Methods for preparing and using the compounds are also described.

Abstract: Compounds of formula (I), wherein: R.sup.1 is selected from the group consisting of hydrogen and methyl; R.sup.2 is selected from the group consisting of methyl and ethyl; R.sup.3 is selected from the group consisting of hydrogen and methyl; and the C1-C2 carbon-carbon bond may be a single or double bond. Such compounds are useful in the treatment of pathologic conditions that benefit from blockade of isozymes of 5.alpha.-reductase.

Abstract: A process for producing polymorphic Form I of finasteride, 17B-(N-tert-butyl carbamoyl)-4-aza-5.alpha.-androst-1-en-3-one, in substantially pure form comprising the steps of: (1) crystallization from a solution of finasteride in a water immiscible organic solvent and 0% or more by weight of water, producing solvated and non-solvated finasteride in solution, such that the amount of organic solvent and water in the solution is sufficient to cause the solubility of the non-solvated form of finasteride to be exceeded and the non-solvated form of finasteride to be less soluble than any other form of finasteride in the organic solvent and water solution: (2) recovering the resultant solid phase; and (3) removing the solvent therefrom; wherein the water immiscible organic solvent is ethyl acetate or isopropyl acetate and the amount of water in the solvent mixture is below 4 mg./ml.

Abstract: Novel amino substituted 4-azasteroid 5.alpha.-reductase inhibitors of formula (I). ##STR1## wherein A is (a), (b) or (c), are claimed as well as pharmaceutically acceptable salts and formulations thereof. These compounds are effective in inhibiting testosterone 5.alpha.-reductase(s) and are thus useful in the treatment of a number of hyperandrogenic conditions including benign prostatic hypertrophy, acne, seborrhea, female hirsutism, and male and female pattern baldness (alopecia).

Abstract: Novel substituted 4-azasteroid 5-.alpha.-reductase inhibitors of formula (I), wherein A is (a), (b) or (c), are claimed as well as pharmaceutically acceptable salts and formulations thereof. These compounds are effective inhibitors of testosterone 5.alpha.-reductase(s) and are thus useful in the treatment of a number of hyperandrogenic conditions including benign prostatic hypertrophy, acne, seborrhea, female hirsutism, and male and female pattern baldness (alopecia).

Abstract: This invention relates to certain novel compounds and derivatives thereof, their synthesis, and their use as selective alpha-1a adrenergic receptor antagonists. One application of these compounds is in the treatment of benign prostatic hyperplasia. These compounds are selective in their ability to relax smooth muscle tissue enriched in the alpha 1a receptor subtype without at the same time inducing orthostatic hypotension. One such tissue is found surrounding the urethral fining. Therefore, one utility of the instant compounds is to provide acute relief to males suffering from benign prostatic hyperplasia, by permitting less hindered urine flow. Another utility of the instant compounds is provided by combination with a human 5-alpha reductase inhibitory compound, such that both acute and chronic relief from the effects of benign prostatic hyperplasia are achieved.

Abstract: A heterocycle-containing carbonic acid derivative represented by the following general formula (I): ##STR1## or a physiologically acceptable salt thereof which exhibits an excellent preventive and therapeutic effect against various diseases, and an intermediate which is useful for the production of the heterocycle-containing carbonic acid derivative.

Abstract: Compounds of Formula (I), ##STR1## wherein X is sulfur or oxygen are inhibitors of the 5.alpha.-reductase enzyme and isozymes thereof. The compounds are useful for the treatment of hyperandrogenic disease conditions and diseases of the skin and scalp.

Abstract: A tetracyclic compound of the formula: ##STR1## wherein A and the atoms to which it is attached and the optional double bond represent a mono- or di-heterocyclic ring selected from: ##STR2## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and X are specifically defined, which compounds are useful in the treatment of dopamine-related neurological, psychological and cardiovascular disorders as well as in the treatment of substance abuse and other addictive behavior disorders, cognitive impairment and attention deficit disorder.

Abstract: Compounds of the Formula I ##STR1## wherein: the dotted line indicates that a double bond may be present or absent; R.sup.1 is H, methyl or ethyl; R.sup.2 is .alpha.- or .beta.-C.sub.1-10 straight or branched alkyl; R.sup.3 is CO.sub.2 H, CN, CO.sub.2 R.sup.4, COHNR.sup.4, or CON(R.sup.4).sub.2 ; R.sup.4 is H, C.sub.1-10 straight or branched alkyl, aryl, heteroaryl, or aralkyl; Aryl is phenyl, substituted phenyl, naphthyl, or biphenyl; Heteroaryl is pyridyl, pyrrolyl, thienyl, furanyl or quinolinyl; and Aralkyl is C.sub.1-10 alkyl substituted with one to three phenyl or substituted phenyl moieties; and their pharmaceutically acceptable salts are described. These compounds are 5.alpha.-reductase type 1 inhibitors. They may be used for treating conditions associated with an excess of DHT, either alone or in combination with other 5.alpha.-reductase inhibitors.

Abstract: By this invention, there is provided a process for producing crystalline 4,7.beta.-dimethyl-4-aza-5.alpha.-cholestan-3-one of structural formula (I) from 4,7.beta.-dimethyl-4-aza-5.alpha.-cholestan-3-one oil. ##STR1## This crystallization process of the present invention comprises crystallization of the oil optionally containing residual solvent with vigorous but controlled agitation. Preferably, this crystallization process is carried out at select and controlled temperatures. Further, 4,7.beta.-dimethyl-4-aza-5.alpha.-cholestan-3-one has been found to exist in at least two novel polymorphic nonsolvated forms, herein referred to as Form I and Form II. Form I can be prepared pure by careful control of the crystallization process.

Abstract: The invention relates to novel 4-azaandrostene intermediates of formula (I), ##STR1## wherein R is hydrogen or a C.sub.1-3 alkyl group;X is chlorine, bromine or iodine; and the---- bond line is a single or double bond.

Abstract: The invention relates to novel 17.beta.-substituted 4-azaandrostane derivatives of general formula (I), ##STR1## wherein R means hydrogen or a C.sub.1-3 alkyl group;R.sup.1 and R.sup.2 are the same or different and stand for hydrogen or a C.sub.1-4 alkyl group with the proviso that both can mean hydrogen only in the case when n is higher than 5; orR.sup.1 and R.sup.2 together means an .alpha.,.omega.-alkylene group containing 5 to 7 carbon atoms, the terminal carbon atoms of said alkylene group being bound to the same ring carbon atom;n is 4, 5, 6 or 7; and--- bond line represents a single or double bond.Furthermore, the invention relates to pharmaceutical composition containing these compounds as well as a process for the preparation of the compounds of general formula (I).The compounds of general formula (I) exert a 5.alpha.

Abstract: Described is a new process for producing 7.beta.-substituted-4-aza-5.alpha.-androstan-3-ones and related compounds which are 5.alpha.-reductase inhibitors, consisting of reducing the corresponding androsteneone with lithium and liquid ammonia, contacting the product with an isomerizing agent, oxidizing the product to a seco acid and reacting that seco acid with an amine to cyclize to form 4-aza-5.alpha.-androstan-3-ones.

Abstract: 17.beta.-N-monosubstituted-carbamoyl-4-5.alpha.-androst-1-en-3-ones of the formula ##STR1## wherein R.sup.1 is selected from hydrogen, methyl and ethyl and R.sup.2 is a branched chain alkyl of from 3-12 carbons, and R', R", R'" are hydrogen or methyl are active as testosterone 5.alpha.-reductase inhibitors and thus are useful topically for treatment of androgenic alopecia.

Abstract: 17.beta.-N-monosubstituted-carbamoyl-4-5.alpha.-androst-1-en-3-ones of the formula ##STR1## wherein R.sup.1 is selected from hydrogen, methyl and ethyl and R.sup.2 is a branched chain alkyl of from 3-12 carbons, and R', R", R"' are hydrogen or methyl are active as testosterone 5.alpha.-reductase inhibitors and thus are useful topically for treatment of androgenic alopecia.

Abstract: The present invention relates to the compound of formula (I), ##STR1## also known as 17.beta.-N-(2,5-bis(Trifluoromethyl))phenylcarbamoyl-4-aza-5.alpha.-andros t-1-en-3-one, solvates thereof, its preparation, intermediates used in its preparation, pharmaceutical formulations thereof and its use in the treatment of androgen responsive and mediated diseases.

Abstract: The invention relates to substituted 17.alpha.-acyl steroidal 5.alpha.-reductase inhibiting compounds. The invention also relates to pharmaceutical compositions containing these compounds and their use for reducing prostate size and treating prostate adenocarcinoma. Further, the invention describes a process for making these compounds by heating the corresponding substituted 17.beta.-acyl steroid in a solvent, such as ethylene glycol or dimethyl sulfoxide (DMSO), in a base, such as sodium or potassium hydroxide.

Abstract: Compounds of Formula I ##STR1## wherein Z contains an ether or thioether moeity, are inhibitors of the 5.alpha.-reductase enzyme and isozymes thereof. The compounds are useful for the treatment of hyperandrogenic disease conditions and diseases of the skin and scalp.

Abstract: Described are new 7.beta.-substituted 4-aza-5.alpha.-cholestan-3-ones and related compounds as 5.alpha.-reductase inhibitors.

Abstract: Invented are 17.beta.-substituted acyl-4-aza analogues of steroidal synthetic compounds, pharmaceutical compositions containing these compounds, and methods for using these compounds to inhibit steroid 5-.alpha.-reductase. Also invented are intermediates and processes used in preparing these compounds.

Abstract: Compounds of the formula ##STR1## are inhibitors of 5.alpha.-reductase and are useful alone or in combination with other active agents for the treatment of hyperandrogenic disorders such as acne vulgaris, seborrhea, female hirsutism, male pattern baldness, and benign prostatic hyperplasia.

Abstract: Compounds of the formula ##STR1## are inhibitors of 5 .alpha.-reductase and are useful alone or in combination with other active agents for the treatment of hyperandrogenic disorders such as acne vulgaris, seborrhea, female hirsutism, male pattern baldness, and benign prostatic hyperplasia.

Abstract: Described are delta 17 and delta 20 olefinic and saturated 17 Beta-substituted 4-aza-5 alpha-androstan-3-ones and related compounds having 5 alpha reductase inhibitors for treatment of benign prostatic hyperplasia and other hyperandrogenic related disorders.

Abstract: Described are new 17.beta.-ester, amide and ketone 4-aza-5a-androstan-3-ones and related compounds and their use as 5a-reductase inhibitors for treatment of benign prostatic hyperplasia and other hyperandrogenetic related disorders.

Abstract: The novel process of this invention involves the reduction of certain .DELTA.-5 steroidal alkenes to selectively produce either the 5.alpha. or 5.beta. reduction products. Particularly, this invention involves reduction of .DELTA.-5 steroidal alkenes using a rhodium based catalyst in the presence of hydrogen to selectively yield 5.alpha. steroids or alternatively reduction of .DELTA.-5 steroidal alkenes in an ionizing medium with a trialkylsilane to selectively yield 5.beta. steroids.

Abstract: Disclosed is a new process for producing finasteride which involves reacting the magnesium halide salt of 17.beta.B-carboalkoxy-4-aza-5.alpha.-androst-1-en-3-one with t-butylamino magnesium halide, present in at least a 2:1 molar ratio to the ester, formed from t-butyl amine and an aliphatic/aryl magnesium halide at ambient temperature in an inert organic solvent under an inert atmosphere followed by heating and recovering said product finasteride.Also disclosed are two polymorphic crystalline Forms I and II of finasteride, and methods of their production.

Abstract: A class of predominantly hydrophobic non-azo N-substituted 1,8-naphthalimide compounds, each bearing, at its 3-position, a nucleofuge and, at its 4-position, a heteroatomic electron-releasing group. The heteroatomic electron-releasing group is being characterized as having a heteroatom directly linked to the 4-position of the ring, and having at least one hydrogen directly attached to the heteroatom. Upon activation by an activating agent in an environment independent of the presence or absence of oxygen, these compounds generate activated species. The activated species initiate chemical changes in lipid bilayer membranes of viruses and other target cells. These changes can eradicate viruses and other target cells. The activated species can also cause structural changes in lipid and any associated proteins and polypeptides at a level beneath the surface of the membrane, leading to polymerization and crosslinking.

Abstract: A compound of formula (I): ##STR1## wherein R is a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group;A is a single bond or a straight or branched C.sub.1 -C.sub.6 alkylene chain;R.sub.1 is a hydrogen atom or a C.sub.1 -C.sub.6 alkyl group;R.sub.2 is a C.sub.1 -C.sub.6 alkyl group, a C.sub.5 -C.sub.7 cycloalkyl or a C.sub.6 -C.sub.10 cycloalkylalkyl group, aryl or a C.sub.7 -C.sub.10 arylalkyl group, or a C.sub.6 -C.sub.10 heterocyclylalkyl group;R.sub.3 is hydrogen, a C.sub.1 -C.sub.4 alkyl group or an aryl or a C.sub.7 -C.sub.10 arylalkyl group;Z is a C.sub.1 -C.sub.6 alkyl group, an --OR.sub.5 group wherein R.sub.5 is a C.sub.1 -C.sub.6 alkyl group, ##STR2## group wherein each of R.sub.6 and R.sub.7 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.5 -C.sub.7 cycloalkyl, phenyl or R.sub.6 and R.sub.7 taken together with the nitrogen to which they are linked form a pentatomic or hexatomic saturated heteromonocyclic ring; and the symbol represents a single or a double bond, is a testosterone 68 5.alpha.

Abstract: Compounds of formula (I) ##STR1## wherein: the symbol represents a single or a double bond;B is a bond or a straight or branched C.sub.1 -C.sub.6 alkylene chain;R is hydrogen or C.sub.1 -C.sub.4 alkyl;R.sub.1 is hydrogen, C.sub.1 -C.sub.6 alkyl or benzyl;R.sub.2 isa) hydrogen, fluorine, C.sub.1 -C.sub.6 alkyl, C.sub.5 -C.sub.7 cycloalkyl or C.sub.6 -C.sub.9 cycloalkylalkyl; orb) aryl or C.sub.7 -C.sub.10 arylalkyl;R.sub.3 isa) hydrogen, fluorine or C.sub.1 -C.sub.4 alkyl; orb) aryl or C.sub.7 -C.sub.10 arylalkyl;R.sub.4 is hydrogen, fluorine, or is absent when Y is a double bond;R.sub.5 is hydrogen, fluorine or C.sub.1 -C.sub.6 alkyl; and when Y is a single bond, A is hydrogen, fluorine or ##STR2## wherein each of R.sub.6, R.sub.7 and R.sub.8 independently is hydrogen, fluorine or C.sub.1 -C.sub.6 alkyl; and when Y is a double bond, A is a ##STR3## wherein each of R.sub.6 and R.sub.7 is independently hydrogen, fluorine or C.sub.1 -C.sub.6 alkyl; with the proviso that at least one of the groups R, R.sub.1, R.

Abstract: 17.beta.-N-monosubstituted-carbamoyl-4-aza-5.alpha.-androst-1-en-3-ones of the formula: ##STR1## wherein the dotted line can represent a double bond when present,R.sup.1 is selected from hydrogen, methyl and ethyl andR.sup.2 is CONHC(CH.sub.3).sub.2 CHO, andRa is methyl,are described as being useful for the treatment of benign prostatic hypertrophy.

Abstract: Compounds of the formula ##STR1## wherein carbon atoms 1 and 2 are linked by a single bond or a double bond, R.sub.1 is hydrogen, methyl or ethyl, and A is a group of the formula --N(--R.sub.2)--X-- wherein R.sub.2 is hydrogen or C.sub.1 -C.sub.4 alkyl and X is C.sub.1 -C.sub.12 alkylene or C.sub.3 -C.sub.6 cycloalkylidene; a group of the formula --N(--R.sub.2)--Y--Phe-- wherein R.sub.2 is as defined above, Y is a direct bond or C.sub.1 -C.sub.6 -alkylene and Phe is an unsubstituted or substituted phenylene radical; a group of the formula --O--X-- wherein X is as defined above, or a group --O--Y--Phe-- wherein Y and Phe are as defined above, are inhibitors of 5.alpha.-reductase and can be used for the therapeutic treatment of the human and animal body.

Abstract: Compounds of the formula ##STR1## or a pharmaceutically acceptable salt or ester thereof, wherein R.sup.1 is selected from the group consisting of hydrogen and C.sub.1-10 alkyl;R.sup.2 is selected from the group consisting of hydrogen and C.sub.1-10 alkyl;R.sup.3 is selected from the group consisting of C.sub.1-10 alkoxyl, C.sub.1-10 alkyl and cyano;R.sup.4 is selected from the group consisting of C.sub.1-10 alkenyloxyl, C.sub.1-10 alkoxyl, C.sub.1-10 alkyl, C.sub.1-10 alkylcarbamic, C.sub.1-10 alkylcarbonyloxyl, carbonyl, hydroxyl, and --NHR.sup.5, andR.sup.5 is selected from the group consisting of hydrogen and C.sub.1-10 alkylcarbonyl. Such compounds are useful as selective antagonists of testosterone 5.alpha.-reductase 1.

Abstract: The preparation of a compound of formula (I) ##STR1## wherein X is oxygen or sulphur; R.sub.1 is hydrogen or C.sub.1 -C.sub.6 alkyl; each of R.sub.2 and R.sub.3 is, independently, hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.5 or C.sub.6 cycloalkyl or C.sub.6 -C.sub.9 cycloalkylalkyl; R.sub.4 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 - or C.sub.6 cycloalkyl, C.sub.6 -C.sub.9 cycloalkylalkyl or aryl; and the symbol represents a single or a double bond; by a multi-step process is disclosed.