Abstract: For the continuous hydrolysis of organochlorosilane, a reaction system comprising at least three stages of hydrolysis is used. Each stage includes a reactor and a phase separator wherein hydrolysis is effected to form a hydrolysis mixture which is separated into a hydrolyzate and a hydrogen chloride-containing aqueous medium. The separated aqueous medium is circulated to the reactor. The hydrolyzate is conveyed to the reactor of the subsequent stage. The organochlorosilane is fed into the first stage reactor, the aqueous medium containing an amount of water corresponding to the consumption in one stage is fed into one stage reactor from the subsequent stage, and an amount of water corresponding to the consumption in the overall reaction system is fed in the last stage. Then the entire amount of hydrogen chloride generated in multiple stages of hydrolysis is recovered as anhydrous hydrogen chloride from the first stage.

Abstract: Synthetic processes are provided for the solution phase synthesis of oligonucleotides, especially phosphorothioate oligonucleotides, and intermediate compounds useful in the processes. Intermediates having structure are prepared in accord with preferred embodiments.

Abstract: wherein A is hydrogen or a residue afforded by the removal of n hydroxyl groups from an m-valent alcohol, each R is independently a monovalent hydrocarbon group free of aliphatic unsaturation, each R1 is independently a divalent hydrocarbon group containing at least 2 carbon atoms, m and n are natural numbers wherein m≧n, p is 0 or 1, and Y is a phenol group having the formula: wherein R3 is alkyl and q is from 0 to 4. Also, a method of preparing a phenol-functional organosilicon compound.

Abstract: A method for the production of organosilanes functionalized in 3-position by reacting suitable allyl compounds with hydrogen silanes in the presence of a multielement catalyst containing platinum and at least one other element.

Abstract: The invention includes hydrolyzable and polymerizable silanes, methods of making them and using them to obtain silicic acid(hetero)polycondensates and silicic acid(hetero)polymerizates. The hydrolyzable and polymerizable silanes have the formula I, ##STR1## wherein A=O, S, NH or C(O)O; wherein B=a straight chain or branched organic residue with at least one C.dbd.C double bond and from 4 to 50 carbon atoms;R is an alkyl group, alkenyl group, aryl group, alkylaryl group or an arylalkyl group;R' is a substituted or unsubstituted alkylene group, arylene group, arylenealkylene group or alkylenearylene group each having zero to ten carbon atoms, with the proviso that the substituted groups each have at least one oxygen atom, sulfur atom and/or amine group substituent;R.sup.

Abstract: Synthetic processes are provided wherein substituted silylalkyl phosphoramidites serve as coupling reagents for preparing phosphate, phosphorothioate, and other phosphorous-containing covalent linkages. Also provided are synthetic intermediates useful in such processes.

Abstract: Compositions with protein kinase C-modulatory, anti-inflammatory and other activities are disclosed.

Abstract: A subject of the invention is the products of formula (I): ##STR1## in which: R.sub.1, R.sub.2 and R.sub.3, identical or different, represent a linear, branched or cyclic alkyl radical, an alkenyl or alkynyl radical, containing up to 8 carbon atoms, optionally substituted by one or more halogen atoms, an aryl radical optionally substituted by one or more halogen atoms, one or more hydroxyl radicals, one or more linear or branched alkyl radicals, optionally substituted by one or more halogen atoms, one or more O-alkyl or S-alkyl radicals optionally substituted by one or more halogen atoms,X represents a hydrogen atom, a halogen atom, an alkyl, alkenyl, alkynyl, O-alkyl, O-alkenyl, O-alkynyl, S-alkyl, S-alkenyl or S-alkynyl radical, optionally substituted by one or more halogen atoms and containing up to 11 carbon atoms, an aryl radical containing up to 14 carbon atoms, a C.tbd.N, NO.sub.2, NH.sub.2, ##STR2## CO.sub.2 alk.sub.3 radical, alk.sub.1, alk.sub.2 and alk.sub.

Abstract: A method of lowering plasma cholesterol level in a patient with hypercholesterolemia, by administration of a compound of formula (1) ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently a C.sub.1 -C.sub.6 alkyl group;Z is a thio, oxy or methylene group;A is a C.sub.1 -C.sub.4 alkylene group; andR.sub.5 is a C.sub.1 -C.sub.6 alkyl or --(CH.sub.2).sub.n --(Ar)wherein n is an integer 0, 1, 2 or 3; and Ar is phenyl or napthyl unsubstituted or substituted with one to three substituents selected from the group consisting of hydroxy, methoxy, ethoxy, chloro, fluoro or C.sub.1 -C.sub.6 alkyl.

Abstract: There is disclosed a polyorganosiloxane and a method for the preparation thereof, said polyorganosiloxane having the formula ##STR1## in which R is independently selected from substituted or unsubstituted monovalent hydrocarbon groups, m is an integer having a value of 0 to 500, n is an integer having a value of 0 to 500 and X is selected from a substituted or an unsubstituted monovalent hydrocarbon group or a hindered phenol group which is linked through either a carboxylate ester or an amide moiety, with the proviso that at least one of the X groups is said hindered phenol group.

Abstract: The hydrolyzable and polymerizable silanes have the formula I, ##STR1## wherein X is hydrogen, a halogen, a hydroxy, an alkoxy group, an acyloxy oup, an alkylcarbonyl group, an alkoxycarbonyl group or --NR.sup.2.sub.2 group; wherein R.sup.

Abstract: An improved aqueous electrocoating composition that contains an anticrater agent which is a reaction product of polyoxyalkylene diamine and glycidoxy alkyl alkoxy silane which is hydrolyzed and has a number average molecular weight of about 700-5,000; electrodeposited finishes are formed that have a significant reduction in craters and are smooth and even finishes.

Abstract: Synthetic processes are provided wherein substituted silylalkyl phosphoramidites serve as coupling reagents for preparing phosphate, phosphorothioate, and other phosphorous-containing covalent linkages. Also provided are synthetic intermediates useful in such processes. h processes.

Abstract: The present invention relates to a hydroxyphenyl-functional polyorganosiloxane compound having the formula ##STR1## wherein R is independently a monovalent hydrocarbon group free of aliphatic unsaturation, A is a substituted or unsubstituted hydroxyphenyl group, B is selected from the group consisting of alkyleneoxyalkylene groups having at least two carbon atoms and alkylene groups having at least 2 carbon atoms, m is zero or 1, and n is an integer from 0 to 400. The hydroxyphenyl-functional polyorganosiloxanes of this invention are useful as surfactants or as additives for organic polymers.

Abstract: The invention includes hydrolyzable and polymerizable silanes, methods of making them and using them to obtain silicic acid(hetero)polycondensates and silicic acid(hetero)polymerizates. The hydrolyzable and polymerizable silanes have the formula I, ##STR1## wherein A=O, S, NH or C(O)O;whereinB=a straight chain or branched organic residue with at least one C.dbd.C double bond and from 4 to 50 carbon atoms;R is an alkyl group, alkenyl group, aryl group, alkylaryl group or an arylalkyl group;R' is a substituted or unsubstituted alkylene group, arylene group, arylenealkylene group or alkylenearylene group each having zero to ten carbon atoms, with the proviso that the substituted groups each have at least one oxygen atom, sulfur atom and/or amine group substituent;R.sup.

Abstract: The individual enantiomers of the compounds (Ia), (Ib), (IIa) or (IIb), optionally substituted by non-interfering substituent(s). The novel enantiomers can be obtained by biotransformation. The (Ia) or (IIa) compounds can be used for the synthesis of chiral carbocyclic nucleosides.

Abstract: There is now provided a polyol composition containing a polyol having polyester linkages and a number average molecular weight of 400 or more, and at least about 8 php of a silicone-containing surfactant polymer. Either mixed into the polyol composition at the time of foaming, mixed into an isocyanate, or both, is an aliphatic or cycloaliphatic C.sub.4 -C.sub.7 hydrocarbon. The polyol composition is used to make a polyisocyanate based closed cell rigid foam by reacting an organic isocyanate and the polyol composition in the presence of an aliphatic or cycloaliphatic C.sub.4 -C.sub.7 hydrocarbon blowing agent.

Abstract: A water soluble water absorption preventing agent mainly comprising an organic silicon compound and/or its partial hydrolytic condensate, represented by the following general formula: ##STR1## wherein R.sup.1 denotes an alkyl group with 1-20 carbon atoms and with a linear chain or branched chain for which a halogen can substitute for part or all of the hydrogen atoms, R.sup.2 denotes a hydrogen atom or an alkyl group with 1-10 carbon atoms and with a linear chain or branched chain, R.sup.3 denotes a hydrogen atom or an alkyl group with 1-8 carbon atoms and with a linear chain or branched chain, m denotes an integer 1-2 and n denotes an integer 1-3 where m+n=3 or 4, p denotes an integer 1-50, and q denotes an integer 0-25.

Abstract: There is now provided a closed cell rigid polyurethane foam made from a polyol composition containing a polyol having polyester linkages and a number average molecular weight of 400 or more, and at least about 8 php of a silicone-containing surfactant polymer. Either mixed into the polyol composition at the time of foaming, mixed into an isocyanate, or both, is an aliphatic or cycloaliphatic C.sub.4 -C.sub.7 hydrocarbon.

Abstract: There is disclosed a heat-resistant agent which exhibits good solubility in various organopolysiloxanes and which confers superior heat-resistance thereto, said heat-resistant agent having the formula ##STR1## wherein R.sup.2 is independently selected from hydrocarbon or halogenated hydrocarbon groups having 1 to 10 carbon atoms, R.sup.1 is independently selected from R.sup.2 or a eugenol residue, m is an integer having an average value of 5 to 500 and n is an integer having an average value of 0 to 500, with the proviso that there is at least one eugenol residue in the molecule. Also disclosed is a composition comprising an organopolysiloxane and the above described heat-resistant agent.

Abstract: There is disclosed an organosilicon compound which contains a silicon-bonded functional group at each molecular chain terminal as well as a terminal -SiH group on a side chain branching from the main chain, said functional group being selected from amino-functional organic groups, epoxy-functional organic groups, hydroxyl group or a group obtained by substituting active hydrogen in the preceding groups with triorganosilyl group.

Abstract: Synthetic processes are provided wherein substituted silylalkyl phosphoramidites serve as coupling reagents for preparing phosphate, phosphorothioate, and other phosphorous-containing covalent linkages. Also provided are synthetic intermediates useful in such processes.

Abstract: This invention relates to compounds of the formula ##STR1## wherein R.sub.1 and R.sub.6 are each independently C.sub.1 -C.sub.6 alkyl;R.sub.2, R.sub.3 and R.sub.4 are each independently hydrogen or C.sub.1 -C.sub.6 alkyl;R is hydrogen or --C(O)--(CH.sub.2).sub.m --Q wherein Q is hydrogen or --COOH and m is an integer 1, 2, 3 or 4;Z is a thio, oxy or methylene group;A is a C.sub.1 -C.sub.4 alkylene group;R.sub.5 and R.sub.7 are each independently a C.sub.1 -C.sub.6 alkyl or --(CH.sub.2).sub.n --(Ar) wherein n is an integer 0, 1, 2 or 3; and Ar is phenyl or naphthyl unsubstituted or substituted with one to three substituents selected from the group consisting of hydroxy, methoxy, ethoxy, halogen, trifluoromethyl, C.sub.1 -C.sub.6 alkyl, or --NR.sub.8 R.sub.9, wherein R.sub.8 and R.sub.9 are each independently hydrogen or C.sub.1 -C.sub.6 alkyl; with the proviso that when R.sub.2 and at least one of R.sub.5 or R.sub.7 is C.sub.1 -C.sub.6 alkyl, and Ar is not substituted with trifluoromethyl or --NR.sub.8 R.sub.

Abstract: A convergent synthesis of 19-nor-vitamin D compounds, specifically 19-nor-1.alpha.,25-dihydroxyvitamin D.sub.3, is disclosed. The synthesis can also readily be utilized for preparing other 1.alpha.-hydroxylated 19-nor-vitamin D compounds. The key step in the synthesis is a suitable application of Lythgoe's procedure i.e. a Horner-Wittig reaction of the lithium anion of a phosphine oxide with a Windaus Grundmann ketone to give, after any necessary deprotection, the desired 19-nor-vitamin D compound.

Abstract: The magnesium complexes of cyclic hydrocarbons and conjugated dienes, such as 1,2-dimethylenecycloalkanes and 1,3-butadienes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4-diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkylditosylates, alkylditriflates, bromoalkylnitriles, esters, or amides serve as a convenient method for synthesizing carbocyclic systems. Significantly, carbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4-diyl)magnesium complexes with carboxylic esters or acid halides whereas low temperatures lead to regioselective synthesis of .beta.,.gamma.-unsaturated ketones. Additionally, .gamma.-lactones, including spiro .

Abstract: A process is disclosed for the removal of the 4-protected hydroxy group from compounds of the following formula: ##STR1## where A is --COOAlkyl and B is hydroxy, or A and B together represent either oxo or .dbd.CHCOOAlkyl, where X.sup.1 and X.sup.2 are the same or different and represent hydrogen or a hydroxy-protecting group, and where X.sup.3 is ##STR2## with a hydrogen radical source, such as tributyltin hydride or tris(trimethylsilyl)silane, and a radical initiator, such as AIBN or irradiation.

Abstract: This invention relates to certain 2,6-di-alkyl-4-silyl-phenols which are useful as inhibitors of LDL lipid peroxidation and as antiatherosclerotic agents.

Abstract: There is disclosed an improved method for preparing a hybrid organodisilanol compound having the formulaHO--R.sup.1 R.sup.2 SiC.sub.n H.sub.2n RC.sub.n H.sub.2n SiR.sup.1 R.sup.2 --OH (I)said method comprising:(A) reacting a dihydridosilane of the formulaR.sup.1 R.sup.2 SiH.sub.2 (II)with a diene of the formulaC.sub.n H.sub.2n-1 RC.sub.n H.sub.2n-1 (III)to provide a dihydrido compound of the formulaH--R.sup.1 R.sup.2 SiC.sub.n H.sub.2n RC.sub.n H.sub.2n SiR.sup.1 R.sup.2 --H (IV); and(B) reacting said dihydrido compound (IV) with a buffered water solution in the presence of a palladium catalyst.

Abstract: Fluorinated silylated aromatic compounds, their intermediates, methods of use in treating diseases associated with deficiencies of cholinergic transmission in the central nervous system and methods for their preparation are disclosed.

Abstract: The magnesium complexes of cyclic hydrocarbons containing conjugated dienes, such as 1,2-dimethylenecycloalkanes, and 1,3-butadienes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4 diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkylditosylates, alkylditriflates, bromoalkylnitriles, esters, or amides serve as a convenient method for synthesizing carbocyclic systems. Significantly, carbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4-diyl)magnesium complexes with carboxylic esters or acid halides whereas low temperatures lead to regioselective synthesis of .beta.,.gamma.-unsaturated ketones. Additionally, .gamma.

Abstract: The present invention relates, in general, to photochemically removable protecting groups, and, in particular, to the use of styrylsilyl groups to protect reactive functional groups, such as, hydroxyl, amino and thiol groups.

Abstract: A process for the selective monoadditon of an olefin or acetylene to a siloxane which contains two reactive Si--H bonds to produce a product in which only one of the two Si--H functions has added across the olefin or acetylene is disclosed. A process for making unsymmetrical siloxanes from symmetrical dihydrosiloxanes and products of both of these processes are also disclosed. Products are represented by the formula I in which R.sup.1 and R.sup.

Abstract: The invention is drawn to cholesterol derivatives in which a cyclopentane ring has been introduced onto the 25-carbon of the side chain and to 24-epimers of these compounds. The compounds are useful intermediates in the production of 26,27-dimethylene-1.alpha.,25-dihydroxyvitamin D.sub.2 and 26,27-dimethylene-24-epi-1.alpha.,25-dihydroxyvitamin D.sub.2. These vitamin D derivatives are useful for the treatment of diseases such as osteoporosis.

Abstract: The invention relates to novel organosilyl and organosiloxanyl derivatives of glycerin ethers of the general formula ##STR1## wherein R represents --OH or the --OCH.sub.2 --CH.dbd.CH--(CH.sub.2).sub.3 --CH.dbd.CH.sub.2 group or the --(R.sup.5).sub.a --R.sup.6 group or the --OCH.sub.2 --CH.dbd.CH--(CH.sub.2).sub.5 --R.sub.4 group.

Abstract: Novel siloxane derivatives represented by general formula (1): ##STR1## A method for producing the siloxane derivatives and agents such as cosmetic preparations, emulsifying dermatotherapeutic external agents and the like including at least one of the siloxane derivatives are also disclosed.

Abstract: The invention relates to a series of novel silicone fluorinated dimethicone copolyols. This class of compounds provides breathable barriers when applied to textiles and paper. These barriers allow for the passage of water and air through the barrier, but do not allow for the passage of oils. The compounds of the present invention are prepared by reacting a silanic hydrogen containing silicone polymer with a vinyl containing fluoro compound and an allyl alcohol alkoxylate.

Abstract: Silanes of the general formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 in the molecule are the same or different and represent aliphatic hydrocarbon groups,R.sup.4 is a divalent hydrocarbon group with 3 to 14 carbon atoms,R.sup.5 is a group having the formula --O(CH.sub.2).sub.b -- or a polyether group having the formula --(OC.sub.n H.sub.2n).sub.c --, whereinb has a value of 1 to 6,n has an average value of 2 to 2.5c has a value of 1 to 10, anda is 0 or 1, which fulfill the condition that they lower the surface tension of a 1% by weight aqueous solution to a value of .ltoreq.25 mN/m at 25.degree. C., measured with a Du Nooy tensiometer. The silanes are biologically degradable, resistant to hydrolysis and have pronounced surface active properties.

Abstract: The protected cyclobutanone of the formula ##STR1## is treated with a dialkylaluminum chloride, an alkylaluminum dichloride, a trialkylaluminum compound, diphenylsilane in the presence of tris(triphenylphosphine) rhodium (I) chloride, or iridium tetrachloride to yield the corresponding diprotected cyclobutanol. This compound is useful as an intermediate in the preparation of antiviral agents.

Abstract: Processes for synthesizing tertiary alkynols by reacting carbonyl-group-containing compounds with alkynes in the presence of a basic catalyst are disclosed. Preferred products are 6,10,14-trimethyl-4-pentadecyn-6-ol compounds having the structure: ##STR1## A preferred, novel compound, 6,10,14-trimethyl-4-pentadecyne-2,6-diol, can be used in the synthesis of Vitamin E or Vitamin K.sub.1.

Abstract: This invention provides method for the preparation of carbinol-modified organopolysiloxane which does not suffer from the secondary reaction problems of the art and which thereby makes possible the production of high-purity carbinol-containing organopolysiloxane.The method involves a platinum-catalyzed addition reaction of an organopolysiloxane having at least 1 silicon-bonded hydrogen atom in each molecule and an organic compound whose molecule contains at least 1 aliphatically unsaturated hydrocarbon group and at least 1 triorganosilyl-blocked carbinol group. Thereafter a desilylation reaction on the organopolysiloxane product is accomplished in an essentially water-free mixture of organic carboxylic acid and alcohol to provide carbinol-modified organopolysiloxane.

Abstract: The present invention provides novel silicone compositions comprising phenol-modified branched and cyclic silicones which provide improved low temperature viscosity properties.

Abstract: Novel hydroxymethyltrialkoxysilanes of the formula: ##STR1## are produced by transesterifying a carboxylic acid ester of hydroxymethyltrialkoxysilane with an alcohol, and distilling the reaction mixture to remove the carboxylate of the alcohol. The carboxylic acid ester of hydroxymethyltrialkoxysilane is prepared by the reaction of an alkali metal carboxylate with chloromethyltrialkoxysilane, which in turn is prepared by the reaction of a trialkylorthoester with chloromethyltrichlorosilane by heating to reflux with removal of alkylchloride, followed by distillation to remove alkyl ester. The hydroxymethyltrialkoxysilanes and carboxylic acid esters thereof, as well as carboxymethyltrialkoxysilanes, are particularly useful in sol-gel processing by undergoing hydrolysis to yield hydroxymethylsilanetriol, and subsequent hydrolysis and polycondensation products.

Abstract: Processes for synthesizing tertiary alkynols by reacting carbonyl-group-containing compounds with alkynes in the presence of a basic catalyst are disclosed. Preferred products are 6,10,14-trimethyl-4-pentadecyn-6-ol compounds having the structure: ##STR1## A preferred, novel compound, 6,10,14-trimethyl-4-pentadecyne-2,6-diol, can be used in the synthesis of Vitamin E or Vitamin K.sub.1.

Abstract: Novel siloxane derivatives represented by general formula (1): ##STR1## A method for producing the siloxane derivatives and agents such as cosmetic preparations, emulsifying dermatotherapeutic external agents and the like including at least one of the siloxane derivatives are also disclosed.

Abstract: The present invention relates to certain bis[4-(2,6-dialkyl)phenol]silane derivatives which are useful as inhibitors of LDL lipid peroxidation and as antiatherosclerotic agents.

Abstract: There are disclosed novel compounds that can be used to derive therefrom a fragment that corresponds to an A-ring which is to be comined with fragments which respectively correspond to C- and D-rings in synthetic formation of vitamin D.sub.3 derivatives by cleaving the 7,8-bondings by means of oxidizing agents following any known process. According to the invention, there is provided an industrially efficient and effective method of manufacturing above compounds that utilizes chemical reaction of allylic acid to add an oxygen function group to position C(1), a method which is completely different from any existing synthetic methods.

Abstract: A method is provided for making silicone-polyphenylene ether graft copolymers by oxidatively coupling a 2,6-dialkylphenol to a monophenol substituted organopolysiloxane macromer which can be prepared by the hydrosilylation of a phenol having a nuclear bound aliphatically unsaturated radical and a monohydrogen organosiloxane.

Abstract: A process for preparing myoinositol polyphosphoric acid from myoinositol via a polyacylmyoinositol, a process for preparing a polysilyl-polyacylmyoinositol from a polyacylmyoinositol, and a process for preparing an optically active myoinositol polyphosphoric acid from the above product or a polysilylmyoinositol.

Abstract: A homopolymer or a copolymer comprises a polymerizable compound represented by formula (I):A--X--COCOOR.sub.1 (I)whereinR.sub.1 represents a hydrogen atom, a C.sub.1 -C.sub.5 alkyl group or an aryl group;X represents an oxygen atom, a sulfur atom, --COO-- or --NR.sub.5 --whereinR.sub.5 is a hydrogen atom or a C.sub.1 -C.sub.5 alkyl group;A represents a C.sub.3 -C.sub.18 alkenyl, alkynyl, alkenylaryl or alkenylaralkyl group, or a group represented by: ##STR1## wherein R.sub.2 and R.sub.3, which may be the same or different, independently represent a hydrogen atom or a C.sub.1 -C.sub.5 alkyl group;Y represents an oxygen atom or --NR.sub.4 -- wherein R.sub.4 represents a hydrogen atom or a C.sub.1 -C.sub.5 alkyl group; n is an integer of 1 to 5; m is an integer of 1 to 10; and l is 0 or an integer of 1 to 20;with the proviso that if Y is present, X is not --NR.sub.5 --. Additionally, disclosed are processes of preparing the homopolymer or copolymer as well as the polymerizable compound.

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.