Abstract: Compounds of formula I, ##STR1## wherein the substituents R.sub.1 -R.sub.4 and a have the given meanings and show an activity against inflammatory conditions.

Abstract: The invention relates to a composition, which may be cosmetic or dermatological, Containing at least one dihydroxyacetone precursor. The invention also relates to a composition, which may be cosmetic or dermatological, containing at least one dihydroxyacetone precursor and a compound capable of converting this precursor into dihydroxyacetone. Finally, the invention relates to such a composition packaged in a specific manner and to the use of the composition for artificial tanning of the skin.

Abstract: Non-steroidal compounds which are high affinity, high specificity ligand antagonists for the androgen receptor are disclosed. Also disclosed are methods for employing the disclosed compounds for modulating processes mediated by the androgen receptor and for treating patients requiring androgen receptor antagonist therapy.

Abstract: Various hydroxy benzaldehyde derivatives including Vanillin, a natural product derived from the vanilla bean that is commonly used as a flavoring agent, is administered by injection (i.v., i.m., s.c., and the like) or intravenous infusion in an effective dose amount to a patient in need of calming or sedation.

Abstract: A method of reducing intraocular eye pressure by topically applying to an affected eye a small but therapeutically effective intraocular eye pressure reducing amount of the compound ethyl ethacrynate.

Abstract: The present invention provides compositions and methods for alleviation of both visible and non-visible, or pre-emergent, dermatological lesions associated with changes in normal keratinization, cutaneous infection, epidermal formation or pilosebaceous function, such as acne, psoriasis, seborrhea, ingrown hairs and pseudofolliculitis barbae, and hyperpigmented skin. The inventive compositions comprise a dermatologically absorbable topical antimicrobial, antibiotic, antibacterial or antifungal agent; a dermatologically absorbable alpha or beta hydroxy acid; and a dermatologically absorbable zinc compound in a suitable carrier.

Abstract: A method is provided for preventing or reducing the risk of hypertension in normotensive patients having insulin resistance by administering a cholesterol lowering drug, such as pravastatin, alone or in combination with an ACE inhibitor, especially one containing a mercapto moiety, such as captopril or zofenopril.

Abstract: Straight-chain alkanoic acids, substituted at the .OMEGA.-carbon atom by a substituted phenyl, naphthyl, furyl, or thienyl group and by a substituted 1,4-benzoquinon-2-yl group are effective in the therapy or prophylaxis of conditions associated with lipid peroxide injury to vascular endothelium particularly preeclampsia and eclampsia in pregnant females.

Abstract: This invention relates to a compound of the formula: ##STR1## or a pharmaceutically acceptable salt thereof wherein X is oxygen, sulfur, --CH.dbd.CH--, or --CH.dbd.N--;wherein R.sup.1 is --CO.sub.2 R.sup.2 or tetrazole;wherein R.sup.2 is hydrogen, alkyl of 1 to 6 carbons or a pharmaceutically acceptable cation;wherein R is an alkyl of from 1 to 20 carbons, --(CH.sub.2).sub.p CF.sub.3 or --(CH.sub.2).sub.q R.sup.3 wherein R.sup.3 is alkoxy, phenoxy or alkoxy substituted phenoxy wherein the alkoxy group has from 1 to 8 carbons;wherein p and q are integers from 0 to 20;wherein n is 0 or 1; andwherein m is 0, 1, 2, or 3.

Abstract: Lipid-selective antioxidants of the formula I(A).sub.a (L)(X).sub.a, (I),in whichA=an antioxidative component,L=a bridging member,X=a lipophilic componenta and a'=independently of one another the numbers 1 or 2.The compounds are used for the protection of lipid-containing substances against oxidation and in pharmaceuticals for the prophylaxis and treatment of diseases in which bioradicals are involved, in particular of coronary, circulatory and vascular diseases.

Abstract: Novel compounds of the general structural formula I: ##STR1## have endothelin antagonist activity and are therefore useful in treating cardiovascular disorders, such as hypertension, pulmonary hypertension, postischemic renal failure, vasospasm, cerebral and cardiac ischemia, myocardial infarction, endotoxic shock, inflammatory diseases including Raynaud's disease and asthma.

Abstract: Compounds having the formula I: ##STR1## are inhibitors of the PLA.sub.2 s enzymes. These compounds are useful as anti-allergic, anti-asthmatic, they are also useful in treating various inflammatory diseases such as rheumatoid arthritis, osteoarthritis, bursitis, psoriasis; immunoinflammatory disorders such as contact dermatitis, irritable bowel disease and the like.

Abstract: There are described new 1-alkoxyhexatriene-2-carboxylates of the formula (I) ##STR1## in which R represents substituted phenyl,and a plurality of processes for their preparation.The new 1-alkoxyhexytriene-2-carboxylates are used as pesticides.

Abstract: Compounds of the formula I ##STR1## where n, W, X, Y, Z, R.sup.1, R.sup.2, and R.sup.3 are as defined herein exhibit fungicidal, insecticidal, and acaracidal activity.

Abstract: The present invention provides alkyl and alkylbenzyl ethers of substituted hydroquinones and pharmaceutical compositions containing them. The present invention further provides methods of using these compounds and compositions to inhibit monoamine oxidase, particularly monoamine oxidase B. The present invention further provides methods for the treatment of diseases involving monoamine oxidase.

Abstract: Alpha-Arylacrylic acid derivatives of the general formula I ##STR1## where X is ethylene or ethenylene; n is 0 or 1;m is 0, 1, 2, 3 or 4;R.sup.1 is cyano, cyanato, thiocyanato, nitro, hydroxyl, carboxyl, haloalkyl, haloalkoxy, unsubstituted or substituted cycloalkyl, cycloalkenyl, cycloalkadienyl, alkenyl, alkynyl or amino, alkylcarbonyl, alkoxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, unsubstituted or substituted benzyloxycarbonyl, benzoyl, phenylalkyl, phenylalkoxy or phenoxyalkyl,or R.sup.1 together with one of the radicals R.sup.2 forms an unsubstituted or substituted 1,3-butadiene-1,4-diyl group or an unsubstituted or substituted chain consisting of carbon members and an oxygen member, andR.sup.2 is halogen, unsubstituted or substituted alkyl, alkoxy, alkenyloxy, alkynyloxy, alkadienyloxy, benzyloxy or benzylthio, are used for controlling pests.

Abstract: Derivatives of 3,3,5-trimethylcyclohexanol methyl-2-propionate, preparation method, and therapeutical compositions containing them. Such derivatives have general formula (I).

Abstract: A series of non-peptide derivatives that are antagonists of the fibrinogen IIb/IIIa receptor and thus are platelet aggregation compounds useful in the prevention and treatment of diseases caused by thrombus formation.

Abstract: Phenoxyalkylcarboxylic acid derivatives represented by the following formula (I) ##STR1## having a strong and selective leukotriene antagonistic action and useful for prophylaxis and therapy of allergic diseases as asthma and processes of preparing the same.

Abstract: Disclosed is a 3-(unsubstituted or substituted benzyl)-1-alkyl-2-oxocyclopentane carboxylic acid alkyl ester derivative as represented by the general formula (I): ##STR1## where R.sup.1 and R.sup.2 are each a lower alkyl group;X is a halogen atom, a cyano group, an alkyl group, a haloalkyl group, a phenyl group or a nitro group; andm is 0 or an integer from 1 to 5 and when m is greater than 1 each X can be the same or different.Further, disclosed is a method for the preparation of the compound (I) by carrying out the benzylation, rearrangement, and alkylation from the 2-oxocyclopentane carboxylic acid alkyl ester derivative without isolation of any intermediate compound. In addition, a fungicide is provided in which the 3-(unsubstituted or substituted benzyl)-1-alkyl-2-oxocyclopentane carboxylic acid alkyl ester derivatives (I) is contained as an active ingredient.

Abstract: This invention encompasses compounds and pharmaceutical compositions comprising a pharmaceutical carrier and an effective lipoxygenase inhibiting amount of a compound of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are the same or different members of the group consisting of 1,1-dimethylethyl, halo, phenyl and substituted phenyl wherein the substituents are selected from the group consisting of halo, hydroxy, lower alkyl and lower alkoxy, Alk is straight or branched chain lower alkylene; and R.sub.3 is lower alkoxycarbonylloweralkyl.

Abstract: A compound of the formula ##STR1## wherein R.sub.1 is an organic radical having at least 2 carbon atoms;R.sub.2 is an organic radical; andA.dbd.CO,CH.sub.2, or CHR.sub.3 where R.sub.3 is unsubstituted or substituted alkyl; andZ.sub.1 and Z.sub.2 are independently selected from hydrogen, halogen, and (C.sub.1 -C.sub.4)alkyland use as a fungicide and biocide.

Abstract: An improved method for the decarbalkoxyation of alkylated .beta.-keto esters to obtain high yields of ketones. In accordance with the method, decarbalkoxylation of alkylated .beta.-keto esters is accomplished by heating the esters in the presence of dilute aqueous alkali and an effective amount of a phase-transfer agent. The method produces commercially practical yields of ketone in a manner which is facile, economical and environmentally safe. Novel methylene-linked pyrethroid ketones produced from the improved method exhibit insecticidal activity against various agricultural pests.

Abstract: Provided are cyclic hydrocarbons of Formula I ##STR1## with an aminoalkyl sidechain that are useful for treating phospholipase A2 mediated conditions, diabetes, and obesity.

Abstract: There are disclosed 3-substituted and 3,3-disubstituted all-trans-4-oxoretinoic acids and 3-substituted and 3,3-disubstituted 13-cis-4-oxoretinoic acids and their lower alkyl esters.

Abstract: Lipophilic quaternary ammonium salicylate, characterized in that it corresponds to the formula: ##STR1## in which: (i) R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be identical or different, denote an alkyl or alkylcycloalkyl radical, optionally substituted or interrupted;(ii) R.sub.3 and/or R.sub.4 denote(s) a group:R.sub.8 [OC.sub.2 H.sub.3 R.sub.7 ].sub.n [OCH.sub.2 CHOH--CH.sub.2 ].sub.pin which 0.ltoreq.n.ltoreq.4 and p denotes 0 or 1; R.sub.8 denotes H or an alkyl, alkenyl, alkylcycloalkyl or alkylaryl radical;(iii) R.sub.4 denotes an alkylphenyl radical;(iv), (v) R.sub.1 and R.sub.2 can form a saturated or unsaturated aromatic or non-aromatic heterocycle;(vi) R.sub.1, R.sub.2 and R.sub.3 form polycyclic derivatives with the nitrogen atoms; R.sub.5 denotes a group corresponding to the formula: ##STR2## in which n is an integer varying between 0 and 10.

Abstract: This invention relates to a compound of the formula: ##STR1## or a pharmaceutically acceptable salt thereof wherein X is oxygen, sulfur, or --CH.dbd.CH--;wherein Z is OR.sup.1 or --NR.sup.4 R.sup.5 ;wherein R.sup.1 is hydrogen, lower alkyl, or a pharmaceutically acceptable cation;wherein R.sup.2 is H, --CH.sub.3 or --C.sub.2 H.sub.5 ;wherein R.sup.3 is OH, H or --O;wherein R.sup.4 and R.sup.5 may independently be hydrogen, or lower alkyl having 1-6 carbon atoms, or R.sup.4 and R.sup.5 may act together with N to form a cyclic amide of the formula: ##STR2## wherein n is an integer from 4-5; and m is an integer from 0-4. More particularly, this invention relates to compounds of the above formula which have utility as LTB.sub.4 antagonists.

Abstract: The growth rate of an animal is stimulated by administering to the animal a growth promoting amount of a compound of the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5, which can be the same or different, are each selected from the group consisting of hydrogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms and halogen; X is selected from carbonyl and a ketal group of the formula ##STR2## wherein R.sub.6 and R.sub.7, which can be the same or different, are each selected from hydrogen and alkyl having 1 to 3 carbon atoms; A is a linear or branched alkylene having from 1 to 8 carbon atoms; and R.sub.8 and R.sub.9, which can be the same or different, are each selected from the group consisting of hydrogen, alkyl having 1 to 4 carbon atoms, or 2-hydroxy-alkyl wherein the alkyl group has 2 to 4 carbon atoms, or R.sub.8 and R.sub.

Abstract: Styryl ketones of the formula ##STR1## wherein R.sup.8 and R.sup.9 are independently hydrogen or lower alkyl or together represent an additional carbon-carbon bond andR.sup.10 is a group of the formula ##STR2## as well as corresponding compounds of the formula ##STR3## wherein R.sup.10' is a group of formula (a), (b), (d) or (e) or a group of the formula--C(R.sup.18)(R.sup.19)OR.sup.20' ; (f')have mucosa-protective and/or gastric acid secretion-inhibiting properties, such that they can be used for the control or prevention of illnesses of the gastrointestinal tract, especially against gastric ulcers or duodenal ulcers.

Abstract: Substituted alkadienes of the formula: ##STR1## in which R.sub.1 is hydroxy or acetoxy, R.sub.2 is hydrogen, carboxy, alkoxycarbonyl, phenyl or benzoyl, andR.sub.3 is alkylthio or alkoxy and R.sub.4 is naphthoyl or optionally substituted benzoyl,or R.sub.3 is alkoxycarbonyl, cycloalkyloxycarbonyl or cyano and R.sub.4 is alkyl, naphthyl, optionally substituted phenyl, alkylthio, naphthylmethanethio, optionally substituted benzylthio, optionally substituted phenylthio, naphthylthio, phenethylthio or allylthio,or R.sub.3 and R.sub.4 form, with the carbon atom to which they are attached, a ring-system of formula: ##STR2## in which R.sub.5 is hydrogen or alkoxy and X is methylene or S inhibit 5-lipoxygenase and are useful, for example, as anti-inflammatories.

Abstract: The invention relates to amino substituted propenoates and their use against fungi.

Abstract: This invention provides certain diphenylmethane derivatives, their pharmaceutical formulations, and their use in treating inflammation and arthritis in mammals.

Abstract: Novel asymmetric thioethers of the formula ##STR1## in which the general symbols have the following meanings: R.sup.0 represents hydrogen or C.sub.1-7 -alkanoyl,R.sup.1 represents C.sub.1-3 -alkyl which may be substituted by one or more halogen atoms having an atomic number of at most 17,R.sup.2 represents an aliphatic radical having from 5 to 15 carbon atoms,A represents ethylene, a single bond or vinylene,B.sup.1 represents C.sub.1-7 -alkylene or phenylene,B.sup.2 represents a single bond, ethylene or phenylene, andM represents an aromatic radical of the partial formula ##STR2## in which the symbols have the following meanings: R.sup.3 represents hydrogen or C.sub.1-4 -alkyl,X represents NH, O, S or if R.sup.4 represents hydrogen, a single bond,one of the symbols R.sup.4 and R.sup.5 represents hydrogen and the other represents the group --CO--R.sup.6, orR.sup.4 and R.sup.5 together represent the radical --CO--C(R.sup.6).dbd.C(R.sup.7)--or--CO--C(R.sup.7).dbd.C(R.sup.6)--orR.sup.4 R.sup.

Abstract: Unsaturated camphor derivatives have an activity in the topical and systemic treatment of acne, psoriasis and other dermatological disorders.

Abstract: Tetralin derivatives of the formula I ##STR1## where X, R.sup.1, R.sup.2 and R.sup.3 have the meanings stated in the description, and their preparation are described. The novel compounds are useful for the treatment of disorders.

Abstract: A phenol derivative of the formulaNU--A--X--R.sup.1wherein NU is a defined phenolic nucleus including a phenyl-hydroxynaphthyl; hydroxyphenyl-naphthyl; phenyl-hydroxyindanyl, phenyl-hydroxybenzothienyl or mono-hydroxyphenyl-ethylene or vinylene nucleus; wherein A is alkylene, alkenylene or alkynylene which may be interrupted by phenylene or other linkages, wherein R.sup.1 is hydrogen, or alkyl, alkenyl, alkynyl, cycloalkyl, halogenoalkyl, alkoxyalkyl, halogenoalkoxyalkyl, aryl or arylalkyl, or R.sup.1 is joined to R.sup.2, and wherein X is --CONR.sup.2 --, --CSNR.sup.2 --, --NR.sup.12 CO--, --NR.sup.12 CS--, --NR.sup.12 CONR.sup.2 --, ##STR1## --SO.sub.2 NR.sup.2 --or --CO--, or, when R.sup.1 is not hydrogen, is --NR.sup.12 COO--, --(PO)R.sup.2 13 , --S--, --SO--or --SO.sub.2 --, wherein R.sup.2 is hydrogen or alkyl, or R.sup.1 and R.sup.2 together form alkylene; wherein R.sup.12 is hydrogen or alkyl, and wherein R.sup.22 is hydrogen, cyano or nitro; or a salt thereof when appropriate.

Abstract: The invention relates to novel [(5,6-dichloro-3-oxo-2,3,9,9a-tetrahydrofluoren-7-yl)]alkanoic acids and alkanimidamides bearing novel functional 9a-substituents, their derivatives and their salts. The compounds are useful for the treatment and prevention of injury to the brain and of edema due to head trauma, stroke (particularly ischemic), arrested breathing, cardiac arrest, Reye's syndrome, cerebral thrombosis, cerebral embolism, the neurological problems caused by AIDS, cerebral hemorrhage, cerebral tumors, encephalomyelitis, spinal cord injury, hydrocephalus, post-operative brain injury trauma, edema due to cerebral infections, various brain concussions and elevated intracranial pressure.

Abstract: New derivatives of 3-benzylidene camphor, process for preparing them and their use as protective agents against UV rays and as medicaments.Derivatives of 3-benzylidene camphor of formula: ##STR1## in which R denotes a hydrogen atom, a methyl or ethyl radical,R' denotes a hydrogen atom, a methyl or ethyl radical,R and R' being unable simultaneously to denote a hydrogen atom,R.sub.1 denotes a --COOR.sub.2, --CONHR.sub.2, --COO.sup.- M.sup.+, --CHO, --CH(OR.sub.4).sub.2 or --CH.sub.2 OR.sub.4 group,R.sub.2 being an alkyl, alkenyl, cycloalkyl or aralkyl radical containing at most 20 carbon atoms, optionally substituted by hydroxy, alkoxy, amine or quaternary ammonium groups,M denoting a hydrogen atom, an alkali metal or a N.sup.+ (R.sub.3).sub.4 group, R.sub.3 being a hydrogen atom or a C.sub.1 to C.sub.4 alkyl or hydroxyalkyl radical,R.sub.4 denoting H, alkyl, cycloalkyl or aralkyl containing at most 20 carbon atoms.Application in cosmetics for protection against UV rays.

Abstract: The present invention relates to novel specifically-substituted phenyl compounds, especially substituted di-tert-butyl phenol derivatives, which are effective as anti-inflammatory, analgesic and/or antipyretic agents. These phenyl compounds are substituted with a low molecular weight alkyl chain which terminates in a specific unsaturated functional group. These unsaturated functionalities are --C.tbd.CH, C.dbd.CH.sub.2, C.dbd.C.dbd.CH.sub.2, and aldehydes in the form of their acetals.The present invention further relates to pharmaceutical compositions which contain an anti-inflammatory agent of the present invention and a pharmaceutically-acceptable carrier.Finally, the present invention relates to methods for treating diseases characterized by inflammation, such as rheumatoid arthritis and osteoarthritis, in humans or lower animals.

Abstract: This invention relates to pharmaceutical compositions containing a class of 5-phenyl-1,3-dioxoalkenyl compounds useful as inhibitors of leukotriene biosynthesis and thus useful in the treatment of conditions associated with leukotrienes. This invention also relates to the use of the 5-phenyl-1,3-dioxoalkenyl compounds in the inhibition of leukotriene biosynthesis and thus in the treatment of conditions associated with leukotrienes. This invention further relates to a novel process for the preparation of the 5-phenyl-1,3-dioxoalkenyl compounds.

Abstract: This invention relates to novel organic trithio oxides of the formula:R.sup.1 --X --R--X.sup.1 --R.sup.1wherein R is selected from --CH.sub.2 CH.dbd.CH--, ##STR1## and (CH.sub.2).sub.3 ; X is selected from ##STR2## X.sup.1 is selected from --S--S, ##STR3## and, each R.sup.1 is independently selected from carboxyalkyl, alkoxy, alkylthio, amino, alkylamino and acyl substituted and unsubstituted lower alkyl, lower alkenyl, lower alkynyl, phenyl and lower alkylphenyl; provided when R is --CH.sub.2 CH.dbd.CH--, X is ##STR4## and X.sup.1 is --S--S--, then R.sup.1 is not in both instances --CH.sub.2 CH.dbd.CH.sub.2.This invention also relates to a method of preparing the above-identified compounds by heating and further oxidizing various oxides of organic disulfides and to antithrombotic uses of the compounds.

Abstract: Aryl oxo-alkynoates are 5-lipoxygenase inhibitors, making them useful for the treatment of inflammation, chronic obstructive lung disease or psoriasis. These compounds have the formula: ##STR1## wherein n is 1-12;R.sup.1 is C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, or phenyl; andAryl is naphthyl, phenyl or phenyl substituted with a variety of groups.

Abstract: The present invention provides thioethers of the general formula: ##STR1## wherein Ar is a phenyl radical which is optionally substituted one, two or three times by alkyl, alkenyl, alkoxy, alkylthio, alkanoyl, hydroxyl, hydroxyalkyl, carboxyl, alkoxycarbonyl, carbamoyl, nitro, amino or halogen, Q is an oxygen or sulphur atom or an NH group, A is a straight-chained or branched C.sub.2 -C.sub.8 alkylene radical which is optionally substituted by a hydroxyl group or can be interrupted by an ethenylene or ethynylene group, n is 0, 1 or 2, and R is a hydrogen atom or a straight-chained or branched alkyl radical which is optionally substituted one or more times by the same or different radicals selected from alkoxycarbonyl, alkoxy, hydroxyl, carboxyl or optionally substituted carbamoyl or amino; as well as the pharmacologically acceptable salts thereof, with the proviso that A cannot be ethylene when Ar is a phenyl radical, Q is an oxygen atom and R is the group --CH.sub.2 COOH.

Abstract: Antivirally active compounds of the formula ##STR1## wherein R.sup.1 represents hydroxy, acyloxy derived from an aliphatic acid having 2-18 carbon atoms or a heterocyclic carboxylic acid containing nitrogen atom(s), lower alkoxycarbonyloxy, aminoacyloxy or carboxyalkanoyloxy;R.sup.2 represents lower alkoxy;R.sup.3 represents hydrogen or lower alkoxy; andR.sup.4 represents phenyl which may be substituted by one or more substituents selected from the group consisting of lower alkyl, lower alkoxy, benzyloxy, allyloxy, alkylthio, dialkylamino, amino, cyano, hydroxy, halo and alkylenedioxy; or pyridyl, furyl, thienyl or pyrrolyl which may be substituted by lower alkyl,pharmaceutical compositions containing them and a process for the preparation of those compounds of formula I which are novel.

Abstract: Esters of a benzoyl alkanoic acids and a benzylic alcohol as a growth promoting agent for a wide variety of animals are provided. The esters influence production of growth hormones resulting in an increase in weight/growth in animals.

Abstract: Compounds of the formula (I): ##STR1## in which R.sub.1 represents alkyl containing from 1 to 18 carbon atoms, R.sub.2 represents hydrogen or alkyl containing from 1 to 8 carbon atoms and R represents hydrogen or alkyl containing from 1 to 8 carbon atoms, as well as the alkali metal, alkaline-earth metal or amine salts thereof, in which R represents hydrogen. Also, method of preparing same, compositions containing same and therapeutic treatment therewith.

Abstract: This invention relates to a topical cosmetic preparation for treating oily hair or seborrhea which contains a sebosuppressively effective amount of at least one 4-aryl-4-oxo-but-2-enoic acid derivative.

Abstract: Novel phenylacetic ester derivatives (I) ##STR1## are produced by reacting ketoprofene with alkylene glycol compounds. The derivatives (I) are useful as a nonsteroidal antiphlogistic and analgesic agent with very reduced side effects comparing with sole use of ketoprofene.

Abstract: 1,8-dihydroxy-9-anthrone derivatives, substituted in the 10-position by an unsaturated radical, are described which have utility as ingredients in human and veterinary pharmaceutical and cosmetic preparations and which are compounds of the structural formula ##STR1## wherein R.sub.1 represents a hydrogen atom or a --CO.sub.2 R'.sub.2 radical,R.sub.2 and R'.sub.2 identical or different, represent a hydrogen atom, a linear or branched chain alkyl radical having 1 to 6 carbon atoms, a cycloalkyl radical having 4 to 6 carbon atoms or a benzyl radical,or R.sub.1 and R.sub.2 taken together form a radical --CO--, andn is 0 or 1,with the proviso that when n is 0 and R.sub.1 is --CO.sub.2 R'.sub.2, R.sub.2 and R'.sub.2 do not simultaneously represent the radical CH.sub.3,and the isomers of the compounds of formula (I) and mixtures thereof.