Abstract: The present invention relates to a process for the preparation of compounds of the formula (1)R.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 ArCOOR (1)in which R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are identical or different and are hydrogen, a halogen, an alkyl or alkoxy group having 1 to 6 carbon atoms, OR, NHR, NR.sub.2, SR or COOR, R being an alkyl radical having 1 to 4 carbon atoms, Ar is an aryl radical having 6 to 12 carbon atoms and the radical R identified in formula (1) has the above meaning, by reacting a compound of the formula (2)R.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 ArCOOH (2)in which R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are identical or different and are hydrogen, a halogen, an alkyl or alkoxy group having 1 to 6 carbon atoms, OH, NH.sub.2, NHR, SH or COOH and Ar has the same meaning as in formula (1), with a sulfate of the formula (RO).sub.2 SO.sub.

Abstract: Diphenylheteroalkyl derivatives of the formula I ##STR1## where A and R.sup.1 -R.sup.6 have the meanings specified in the description, and the preparation thereof are described.The substances are suitable for controlling diseases and as cosmetic agents.

Abstract: There is provided a carboxylic acid compound represented by the following formulae (I) to (IV): ##STR1## a liquid crystal material consisting of the carboxylic acid ester compound, a liquid crystal composition comprising the carboxylic acid ester compound, and a liquid crystal element using the carboxylic acid ester compound. There can be obtained advantages such as low operating temperature, high speed switching, very small electric power consumption, and high-stable contrast.

Abstract: Novel indane and indene derivatives are described which are endothelin receptor antagonists.

Abstract: The present invention relates to an enzymatic process for the preparation of optically active tetrahydro-2-naphthoic acids from the corresponding racemic esters by reaction with a lipase.

Abstract: New aromatic dicarboxylic acids, 1,4- or 2,6-Bis(p-carboxyphenoxy)naphthyl is prepared by the reaction of p-fluorobenzonitrile with 1,4-naphthalenediol, followed by hydrolysis. Wholly aromatic polyamides having superior solubility in a variety of organic solvents and have good thermal stability can be obtained by reacting the new aromatic dicarboxylic acids with aromatic diamines. Transparent, tough and flexible films of these polyamides can be cast from the solutions thereof and these polyamides are easily processable high-performance polymer materials.

Abstract: Disclosed are 9-deoxyprostaglandins which are useful in the treatment of glaucoma and ocular hypertension. Some of these 9-deoxyprostaglandins are novel. Also disclosed are ophthalmic, pharmaceutical compositions comprising such prostaglandins.

Abstract: There are herein disclosed an additive for a lubricant or a fuel which comprises at least one selected from the group consisting of substituted hydroxyaromatic ester derivatives represented by the general formulae (I) and (II) ##STR1## wherein R.sup.1 to R.sup.5 are each an organic group having 6 or more carbon atoms, a, b, d, e, k and m are from 1 to 3, c, f, g, i and j are from 0 to 3, and h is from 0 to 4, but (f+g) is from 1 to 3, and (h+i) is from 1 to 6, an additive composition for a lubricant or a fuel, and a lubricating oil composition or a fuel composition containing the above-mentioned additive.The above-mentioned additive for the lubricant or the fuel is desirable as an ashless detergent excellent in high-temperature stability in place of a metal detergent, and the lubricating oil composition or the fuel composition containing this additive can suitably be used as the lubricant or the fuel for an internal combustion engine which can comply with future exhaust gas controls.

Abstract: Prodrugs containing an active drug molecule linked to a polyethylene glycol group, and a method of use thereof are described. Exemplary soluble ester prodrugs contain naproxen, triamcinolone acetonide, gancyclovir, taxol, cyclosporin, dideoxyinosine, trihydroxy steroids, and flurbiprofen molecules linked to polyethylene glycol (PEG) groups. Pharmaceutical compositions containing these prodrugs, and a method of using these esters for treating disease states or symptoms are also described.

Abstract: The present invention relates to benzoquinazoline thymidylate synthase inhibitors, processes for preparing them and pharmaceutical formulations containing them.

Abstract: Abstract of the Disclosure: Diphenylheteroalkyl derivatives of the formula I ##STR1## where A and R.sup.1 -R.sup.6 have the meanings specified in the description, and the preparation thereof are described.The substances are suitable for controlling diseases and as cosmetic agents.

Abstract: Compounds of Formula I ##STR1## wherein the symbols are as defined in the specification.

Abstract: Compounds of the formula ##STR1## wherein the symbols have the meaning described in the specification have retinoid-like biological activity.

Abstract: The present invention concerns a process for enantioselective catalytic hydrogenation of the ketone C.dbd.O double bond to a secondary alcohol function, said process using a neutral ruthenium complex as the catalyst and a compound containing a C.dbd.O group as the substrate to be hydrogenated, characterised in that it comprises hydrogenation of the substrate using a diallyl (diphosphino) ruthenium compound with formula ##STR1## where al preferably represents CH.sub.2 CH.dbd.CH.sub.2 or CH.sub.2 C(CH.sub.3).dbd.CH.sub.2,Q represents a hydrocarbon bridge containing at least two catenary carbon atoms and which can contain one to four catenary heteroatoms selected from O, S, N and Si,R.sup.1 to R.sup.4 may be identical or different and each represents a C.sub.1 -C.sub.18 alkyl, C.sub.5 -C.sub.7 cycloalkyl or C.sub.6 -C.sub.12 aryl group.

Abstract: A process is provided for preparing dioxolenone derivatives of the structure ##STR1## wherein R is alkyl or aryl and R.sub.3 is CO.sub.2 R.sub.2 (where R.sub.2 is alkyl or arylalkyl such as benzyl, diphenylmethyl or para-methoxybenzyl). Intermediates produced in the above process are also provided as well as a method for preparing squalene synthetase inhibitors employing such intermediates.

Abstract: Compounds having the formula ##STR1## methods for using such compounds to inhibit protein kinase C in animals, including man are useful as inhibitors of protein kinase C. Also disclosed are pharmaceutical compositions including such compounds and compounds having the formula.

Abstract: The invention relates to leukotriene-B.sub.4 antagonists of formula I ##STR1## in which n represents a whole number from 2 to 5,X represents a direct bond, 1 to 6 methylene units, an ortho-, meta- or para-substituted phenyl ring or a meta- or para-substituted pyridine ring,Y represents a bond to a hydrogen atom and simultaneously to a hydroxy group, a double-bound oxygen atom or --O--CH.sub.2 --CH.sub.2 --O--,R.sub.1 and R.sub.2 represent the radical OH, --O--(C.sub.1 -C.sub.4)--alkyl, O--(C.sub.3 -C.sub.6)--cycloalkyl, --O--(C.sub.6 -C.sub.10)--aryl, --O--(C.sub.7 -C.sub.12)--aralkyl, O--(CH.sub.2)--CO-- (C.sub.6 -C.sub.10)--aryl or the radical NHR.sub.3 with R.sub.3 meaning hydrogen, (C.sub.1 -C.sub.4)--alkyl, (C.sub.3 -C.sub.6)--cycloalkyl or (C.sub.7 -C.sub.12)--aralkyl as well as their salts with physiologically compatible bases and their cyclodextrin clathrates.

Abstract: Aromatic bicyclic compounds of formula (I) ##STR1## where R.sub.1 is specifically --H, CH.sub.3, --CH.sub.2 OH, --OH, --CHO, --CONH.sub.2, --COOH, --COOalkyl, --SH, S-alkyl, etc. . . . ; R.sub.2 is H; R.sub.3 is H, aryl, aralkyl or lower alkyl optionally substituted by a hydroxyl, a lower alkoxy or a --CO--R.sub.12, R.sub.12 being specifically H, lower alkyl, hydroxyl, lower alkoxy, or R.sub.2 and R.sub.3 together form a naphthalene ring with the benzene ring; R.sub.4 is a linear branched or unbranched alkyl having 1 to 15 carbon atoms or a cycloaliphatic radical; R.sub.5 represents specifically --(CH.sub.2).sub.n --R.sub.13, --CH.dbd.CH--(CH.sub.2).sub.n --R.sub.13, n being 0 or 1 to 6, R.sub.13 representing --COR.sub.15, monohydroxyalkyl, polyhydroxyalkyl, epoxy lower alkyl or --O--CO--R.sub.16, R.sub.15 representing specifically --OH, --Oalkyl, --Oaryl, R.sub.16 being specifically H, lower alkyl, aryl, or aralkyl; R.sub.6 and R.sub.7 are H, a halogen, lower alkyl or --OR.sub.

Abstract: Compounds of Formula 1 ##STR1## wherein X is S or O; R.sub.1 -R.sub.5, m, o, X, Y, A, B are as defined in the specification.

Abstract: A process for preparing olefin compounds of the formula ##STR1## where A is aryl, substituted aryl, heteroaryl, substituted heteroaryl, benzyl, substituted benzyl, vinyl or substituted vinyl and R.sub.2, R.sub.3 and R.sub.4 are hydrogen, alkyl, cycloalkyl, alkyl-substituted cycloalkyl, aryl, substituted aryl, alkoxy, alkythio, heteroaryl, substituted heteroaryl, alkanoyl, aroyl, substituted aroyl, heteroarylcarbonyl, substituted heteroarylcarbonyl, trifluoromethyl or halo, which comprises reacting an organic halide of the formula A-X where X is chloro, bromo or iodo with a vinyl or substituted vinyl compound of the formula ##STR2## where R.sub.2, R.sub.3 and R.sub.

Abstract: There is provided a process for preparing an arylacetic acid or arylpropionic acid divative from an arylcarbinol which comprises the step of subjecting said arylcarbinol to suitable carbonylation conditions for a sufficient period of time and under suitable pressure and temperature to form said acid derivative, with the proviso that said carbonylation conditions include conducting the reaction in a two-phase system wherein one phase is an aqueous medium which contains (1) a catalyst which is a water-soluble metal complex consisting essentially of a Group VIII metal and a hydrophilic ligand such as palladium complexed with trisulfonated triphenylphosphine, and (2) optionally an acid, and wherein the second phase comprises said arylcarbinol.

Abstract: Provided are .alpha.-chain-modified isocarbacyclins of which the .alpha.-chain is modified with a phenylene group, a cycloalkylene group or a thiophendiyl group, and these .alpha.-chain-modified isocarbacyclins show the activity for inhibiting the DNA synthesis of human smooth muscle cell and are expected to be capable of inhibiting the hypertrophy of a blood vessel.

Abstract: Naphthalene derivatives of the formula: ##STR1## wherein R.sup.1, represents a hydrogen atom, a lower alkyl group or an acyl group; R.sup.2 independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a cycloalkyl group, a cycloalkylalkyl group, a hydroxyl group, an aryl group which may be substituted, an arylalkyl group whose aryl group may be substituted, a heteroaryl group, or a heteroaryllakyl group; R.sup.3 represents a hydrogen atom, a lower alkyl group, a lower alkenyl group, an aryl group which may have a substituent, an arylalkyl group whose aryl group may be substituted, an arylalkenyl group whose aryl group may be substituted, a cycloalkyl group, an alkoxyalkyl group, a heteroaryl group, a heteroarylalkyl group, a carboxyl group, a carboxyalkyl group, an aminoalkyl group, or a cyano group; R.sup.6 is C.sub.1-6 alkyl; and m is 0 or an integer of from 1 to 2 useful in treating autoimmune diseases are disclosed.

Abstract: The compounds of the formula I ##STR1## and their pharmaceutical acceptable salts, which are defined herein, are ligands for cholecystokinin and/or gastrin receptors.

Abstract: The present invention provides three optical resolution methods. The first aspect comprises the steps of adding an optically active bifunctional resolving reagent to a bifunctional compound to form a liquid material, precipitating crystals therefrom, and treating the crystals and the liquid material separately with an acidic material, a basic material, or a basic material and an acidic material, to obtain a pair of enantiomers of an optically active bifunctional compound. The second aspect comprises an optical resolution method by which one necessary enantiomer of a pair of enantiomers in an optically active bifunctional compound is exclusively obtained. The third aspect comprises a method for racemizing one unnecessary enantiomer of a pair of enantiomers in an optically active bifunctional compound which is formed by the optical resolution method of the present invention.

Abstract: This invention relates to the use of prostacyclin and carbacyclin derivatives for the production of an agent for the treatment of multiple sclerosis.

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 of formula (I): ##STR1## and their salts and esters have the ability to inhibit the synthesis of cholesterol, and can thus be used for the treatment and prophylaxis of hypercholesterolemia and of various cardiac disorders.

Abstract: Diaromatic compounds, characterized in that they correspond to the following general formula: ##STR1## in which: R.sub.1 is --CH.sub.3, --CH.sub.2 OH, --COR.sub.8 or --CH.sub.2 OCOR.sub.9, R.sub.8 is H, OH, --OR.sub.10, --N(rr') or alkyl, R.sub.10 is alkyl, alkenyl, aryl or aralkyl, r and r' being H, alkyl, aryl, aralkyl, etc., r and r' together form a heterocycle, R.sub.9 is alkyl, alkenyl or a sugar residue, R.sub.2 and R.sub.3 are --OR.sub.11 or --OCOR.sub.11, R.sub.11 is H, alkyl, fluoroalkyl, aryl or aralkyl, R.sub.3 in addition being H, R.sub.4 is H, OH, alkyl, alkoxy, F, Cl or --CF.sub.3, R.sub.5 and R.sub.7 are H, OH, alkoxy, .alpha.-substituted alkyl or .alpha.,.alpha.'-disubstituted alkyl, etc., R.sub.6 is H, OH, alkyl, alkoxy, cycloalkyl, etc., R.sub.5 and R.sub.7 cannot simultaneously be OH or alkoxy and R.sub.4, R.sub.5, R.sub.6 and R.sub.7 cannot simultaneously be H, R.sub.5 and R.sub.6 or R.sub.6 and R.sub.

Abstract: A fused benzeneoxyacetic acid derivative of the formula: ##STR1## wherein ##STR2## is (i) ##STR3## (ii) ##STR4## (iii) ##STR5## or (iv) ##STR6## A is (i) ##STR7## or (ii) ##STR8## R.sup.1 is hydrogen or C.sub.1-4 alkyl; R.sup.2 is hydrogen, C.sub.1-6 alkyl or phenyl;R.sup.3 is(i) C.sub.1-15 alkyl,(ii) C.sub.1-8 alkyl substituted by one or two of benzene, C.sub.4-7 cycloalkane or 4-7 ring-membered monocyclic ring which contains one nitrogen atom or(iii) C.sub.10-15 condensed tricyclic ring;e is 3-5;f is 1-3;p is 0-4;q is 0-2;s is 0-3With the proviso that, ring(s) in R.sup.3 may be substituted by one to three of C.sub.1-4 alkyl, .sub.1-4 alkoxy, halogen atom, nitro or trihalomethyl. And, when D--B is the formula (iii) or (iv), --(CH2)p- or .dbd.CH--(CH2)s- is attached at the position of a or b on the ring.

Abstract: A compound of the formula ##STR1##

Abstract: Compounds of formula ##STR1## Ar is optionally substituted phenyl, furyl, pyridyl, or thienyl; Y is selected from hydrogen, halogen, cyano, alkyl, haloalkyl, alkoxy, and alkoxycarbonyl; L is selected from ##STR2## and R.sup.1 and R.sup.2 are alkyl or together define a group of formula ##STR3## are potent inhibitors of lipoxygenase enzymes and thus inhibit the biosynthesis of leukotrienes. These compounds are useful in the treatment or amelioration of allergic and inflammatory disease states.

Abstract: The present process is directed to preparing optically active 2-aryl alkyl aldehydes by various processes through the use of an optically active amine, (-)-2'-amino-3-phenyl propane. The aldehyde formed can then be oxidized to produce the corresponding acid.

Abstract: In the enzymatic stereoselective ester cleavages of 2-arylpropionate, the reaction rate of the hydrolyzing enzymes can be drastically increased if the vinyl ester of the 2-arylpropionate is employed as the substrate.

Abstract: The invention relates to a preparation process for aromatic methyl methoxycarboxylates by reaction of aromatic hydroxycarboxylic acids in the form of a mixture with the methoxycarboxylic acids with dimethyl sulphate in water.

Abstract: Disclosed is a liquid crystal material represented by the following formula [I]:R--X--A.sup.1 --Y.sup.1 --A.sup.2 --(Y.sup.2 --A.sup.3).sub.n --Z--R*[I]wherein R is an alkyl or polyfluoroalkyl group; X is a group such as --COO--, or a single bond; n is 0 or 1; A.sup.1, A.sup.2 and A.sup.3 are each a cyclic group such as tetralin, and at least one of them has an optically active group; Y.sup.1 and Y.sup.2 are each a group such as --COO--; Z is a group such as --O--, or a single bond; and R* is an optically active group. Also disclosed are a liquid crystal composition comprising the liquid crystal material represented by the above formula, and a liquid crystal element in which the liquid crystal material is used. The liquid crystal material of the invention shows excellent liquid crystal characteristics because it has at least two optically active groups.

Abstract: The present invention relates to a process for the preparation of methyl 5-bromo-6-methoxy-1-naphthoate by brominating methyl 6-methoxy-1-naphthoate with bromine, in which between 0.5 and 0.6 mol of bromine (Br.sub.2) are employed per mole of methyl 6-methoxy-1-naphthoate and the bromination is carried out in the presence of an oxidant.

Abstract: .alpha.-arylacrylic acid derivatives of the general formula I ##STR1## where X is ethylene or ethenylene; Y is a direct bond or oxygen;R.sup.1 is a mononuclear or dinuclear aromatic system substituted by C.sub.1 -C.sub.4 -alkyl, their preparation, insecticides and fungicides containing them and methods for their use.

Abstract: Compounds of formula (Ic): ##STR1## having valuable platelet-aggregation inhibitory activities useful for the prophylaxis and treatment of such diseases as thrombosis and pharmaceutical compositions containing said compounds.

Abstract: Novel substituted cyclic compounds of Formula I are found to be useful inhibitors of matrix metalloendoproteinase-mediated diseases including osteoarthritis, rheumatoid arthritis, septic arthritis, tumor invasion in certain cancers, periodontal disease, corneal ulceration, proteinuria, dystrophic epidermolysis bullosa, and coronary thrombosis associated with atherosclerotic plaque rupture. The matrix metalloendoproteinases are a family of zinc-containing proteinases including but not limited to stromelysin, collagenase, and gelatinase, that are capable of degrading the major components of articular cartilage and basement membranes. The inhibitors claimed herein may also be useful in preventing the pathological sequelae following a traumatic injury that could lead to a permanent disability. These compounds may also be useful as novel birth control agents by preventing ovulation or implantation.

Abstract: A new process for preparing aryl-substituted aliphatic carboxylic acids is provided. Aryl-substituted aliphatic ether or thioether compound is reacted with carbon monoxide in aqueous conditions at a temperature between about 25.degree. C. and about 200.degree. C. An acid such as hydrochloric acid may be added. As catalyst, a mixture of palladium or a palladium compound and a copper compound with at least one acid-stable ligand are present.

Abstract: The present invention provides three optical resolution methods. The first aspect comprises the steps of adding an optically active bifunctional resolving reagent to a bifunctional compound to form a liquid material, precipitating crystals therefrom, and treating the crystals and the liquid material separately with an acidic material, a basic material, or a basic material and an acidic material, to obtain a pair of enantiomers of an optically active bifunctional compound. The second aspect comprises an optical resolution method by which one necessary enantiomer of a pair of enantiomers in an optically active bifunctional compound is exclusively obtained. The third aspect comprises a method for racemizing one unnecessary enantiomer of a pair of enantiomers in an optically active bifunctional compound which is formed by the optical resolution method of the present invention.

Abstract: Alkylphenyl alkyl ethers or alkylphenyl alkyl thioethers, of the formula ##STR1## where U represents O or S; and R.sub.1 -R.sub.6 each independently represent an alkyl or aryl group with 1-6 C atoms, but R.sub.1 -R.sub.5 may each independently represent a functional group other than these, particularly --COOR (R=C.sub.1-4 alkyl), --NO.sub.2, --NH.sub.2, --O--CH.sub.2 --CH.sub.2 --OH, --OH, --CHO, --H, or -halogen;R.sub.1 -R.sub.5 may be bridged by suitable bifunctional substituents, such as, e.g., --(CH.sub.2).sub.x --, or --(CH.sub.2).sub.x --Z--(CH.sub.2).sub.y -- (where Z represents a hetero atom; x=0-7 and y=0-7), or by unsaturated substituents or anellated ring systems; may be produced in high space-time yield by reacting the corresponding phenol or thiophenol with a arylalkyl carbonate at a temperature of 70.degree.-300.degree. C. under elevated or normal pressure, in the presence of a monocyclic, bicyclic, polycyclic, or acyclic amidine as a catalyst.

Abstract: A compound of the formula ##STR1##

Abstract: The invention relates to carbacyclin derivatives of Formula I ##STR1## wherein the various substituents are defined herein, including, inter alia,if R.sub.2 is a hydrogen atom, their salts with physiologically compatible bases, their cyclodextrin clathrates, and their use as medicinal agents.

Abstract: In accordance with the present invention, there are provided carboxylate compounds represented by the following formula [A] and liquid crystal material comprising said compounds ##STR1## wherein R is a group selected from the group consisting of alkyl, alkoxy and halogenated alkyl group of 3-20 carbon atoms, X and Y represent each a group selected from the group consisting of --COO--, --OCO--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O--, --OCH.sub.2 --, --S--S--, ##STR2## or a single bond, A and B represent each a group selected from the group consisting of specific divalent aromatic and alicyclic group such as phenylene, cyclohexylene and tetrahydronaphthalene and R* is an optically active group of 4-20 carbon atoms containing at least one asymmetric carbon atom (hydrogen atoms attached to the carbon atoms of said optically active group may be substituted with halogen atoms), and m and n are each an integer of 0-2, with the proviso that both m and n do not become 0 at the same time.

Abstract: The invention is an expedient route to synthesizing substituted or unsubstituted aryl-2-propenoic esters. The substituted or unsubstituted aryl-2-propenoic esters are useful in preparing optically active substituted or unsubstituted 2-arylpropanoic acids known to be active anti-inflammatory agents.

Abstract: The present invention provides a tetralin compound represented by the following formula:R--X--A.sup.1 --Y.sup.1 --A.sup.2 --(Y.sup.2 --A.sup.3).sub.n --Z--R*wherein R is an alkyl group of 3-20 carbon atoms; X is --O-- CO--, --O-- or a single bond; n is 0 or 1; each of A.sup.1, A.sup.2 and A.sup.3 is a divalent aromatic group; each of Y.sup.1 and Y.sup.2 is --COO--, --O--CO--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O-- or --OCH.sub.2 --; Z is --O--, --O--CO-- or a single bond; and R* is a specific optically active group.The invention also provides a liquid crystal material comprising the above-mentioned tetralin compound, a liquid crystal composition comprising the tetralin compound and a liquid crystal compound other than the tetralin compound, and a liquid crystal element using the tetralin compound. The tetralin compound of the invention is favorably used as a liquid crystal material because it has a large tilt angle and shows excellent liquid crystal properties.

Abstract: A ruthenium-phosphite complex having the formula ##STR1## wherein a is from 1 to 3; b is 1 or 2; c is from 0 to 3; and R is hydrogen, alkyl, aryl, halo, amino, acetylamino, or sulfo; and X is ##STR2## where R.sub.1, R.sub.2, and R.sub.3 are the same or different and are hydrogen or C.sub.1 to C.sub.6 linear or branched alkyl.This complex can be used to effect the reduction of unsaturated organic compounds or, when comprised of ligands having optical activity, can be used as the catalyst for effecting the asymmetric reduction of unsaturated organic compounds.

Abstract: A benzonaphthalene compound has the formula ##STR1## wherein R.sub.1 represents ##STR2## or (ii) --CH.sub.2 OH; R.sub.6 represents ##STR3## or OR.sub.7 wherein R.sub.7 represents hydrogen, alkyl having 1-20 carbon atoms, monohydroxyalkyl or polyhydroxyalkyl, r' or r" represent hydrogen, lower alkyl, mono or polyhydroxyalkyl, aryl or a residue of an amino acid or a sugar, or together form a heterocycle; R.sub.2 represents hydrogen, alkyl having 1-15 carbon atoms, alkoxy having 1-4 carbon atoms or a cycloaliphatic radical; R.sub.3 represents hydrogen, hydroxy, alkyl having 1-4 carbon atoms, alkoxy having 1-10 carbon atoms, a cycloaliphatic radical, a thiocycloaliphatic radical or --O--Si(CH.sub.3).sub.2 --R.sub.8 wherein R.sub.8 represents lower alkyl; and R.sub.4 and R.sub.5 represent hydrogen, lower alkyl, hydroxy or lower acyloxy.This compound is useful in the topical and systemic treatment of dermatologic diseases and in the treatment of the degeneration of conjunctive tissues.