Abstract: This invention relates to the reversible protection of hydroxy-silane functional groups by acid cleavable protecting groups. The development of reversible protecting groups greatly enhances the current utility of silanes while introducing further novel applications. For instance, reversibly protected silanes are of particular value in applications where room temperature cure and/or adhesion is of value, such as coatings, high resolution imaging, caulks, adhesives, sealents, gaskets, and silicones. Reversibly protected silanes can also be beneficially used in reticulating agents, and in sizing agents, tires, and release coatings. The incorporation of reversibly protected silanes into coating resins is of particular value. The reversibly protected silane can be incorporated into the coating resin by polymerizing a monomer containing the reversibly protected silane into the resin or by post-addition into the coating formulation.

Abstract: This invention relates to the reversible protection of hydroxy-silane functional groups by acid cleavable protecting groups. The development of reversible protecting groups greatly enhances the current utility of silanes while introducing further novel applications. For instance, reversibly protected silanes are of particular value in applications where room temperature cure and/or adhesion is of value, such as coatings, high resolution imaging, caulks, adhesives, sealents, gaskets, and silicones. Reversibly protected silanes can also be beneficially used in reticulating agents, and in sizing agents, tires, and release coatings. The incorporation of reversibly protected silanes into coating resins is of particular value. The reversibly protected silane can be incorporated into the coating resin by polymerizing a monomer containing the reversibly protected silane into the resin or by post-addition into the coating formulation.

Abstract: An acetylene alcohol represented by the following formula, wherein R1 represents a monovalent hydrocarbon radical having 4 to 10 carbon atoms with the carbon atom bonded to the silicon atom being a tertiary carbon, R2 and R3 each represents a monovalent group selected from the group consisting of alkyl groups having 1 to 4 carbon atoms and a fluorinated group represented by the formula, Rf—Q—, wherein Rf is a linear or branched perfluoroalkyl group having 3 to 100 carbon atoms which may be interrupted by one or more ether bonds, and Q is a divalent group having 2 to 10 carbon atoms which may be interrupted by one or more nitrogen, oxygen, or sulfur atoms, and n is zero or 1.

Abstract: This invention relates to the reversible protection of hydroxy-silane functional groups by acid cleavable protecting groups. The development of reversible protecting groups greatly enhances the current utility of silanes while introducing further novel applications. For instance, reversibly protected silanes are of particular value in applications where room temperature cure and/or adhesion is of value, such as coatings, high resolution imaging, caulks, adhesives, sealents, gaskets, and silicones. Reversibly protected silanes can also be beneficially used in reticulating agents, and in sizing agents, tires, and release coatings. The incorporation of reversibly protected silanes into coating resins is of particular value. The reversibly protected silane can be incorporated into the coating resin by polymerizing a monomer containing the reversibly protected silane into the resin or by post-addition into the coating formulation.

Abstract: Organometallic complexes are provided, which include a catalyst containing a transition metal, a ligand and a component having the formula GArF. ArF is an aromatic ring system selected from phenyl, naphthalenyl, anthracenyl, fluorenyl, or indenyl. The aromatic ring system has at least a substituent selected from fluorine, hydrogen, hydrocarbyl or fluorinated hydrocarbyl, G is substituted or unsubstituted (CH2)n or (CF2)n, wherein n is from 1 to 30, wherein further one or more CH2 or CF2 groups are optionally replaced by NR, PR, SiR2, BR, O or S, or R is hydrocarbyl or substituted hydrocarbyl, GArF being covalently bonded to either said transition metal or said ligand of said catalyst, thereby rendering said cationic organometallic complex liquid.

Abstract: By reacting &agr;,&bgr;-unsaturated carboxylic esters with hydrosilanes or hydrosiloxanes in the presence of a catalytic amount of tris(pentafluorophenyl)borane, silyl ketene acetals or disilyl ketene acetals with high purity are produced in high yields.

Abstract: A mixture of organoalkoxysiloxanes of formula I: wherein R and R″ are identical or different and are methyl, ethyl, vinyl, n-propyl, i-propyl, &ggr;-chloropropyl, n-butyl, i-butyl, n-pentyl, i-pentyl, n-hexyl, i-hexyl, n-heptyl, i-heptyl, n-octyl, i-octyl, hexadecyl, octadecyl or alkoxy, R′ represents methyl or ethyl, n and m are identical or different and each is 0 or an integer ranging from 1 to 20, on the condition that (n+m)≧2, is prepared by: reacting in a first stage the constituents of (i) an organotrichlorosilane or a mixture of organotrichlorosilanes or a mixture of at least one organotrichlorosilane and tetrachlorosilane, (ii) water and (iii) alcohol, combined in a molar ratio (i):(ii):(iii) of 1:(0.59 to 0.95):(0.5 to 100), at a temperature of 0 to 150° C.

Abstract: A process for the production of a silicon-containing polymer having a main chain of oxygen atoms, organic groups and Si—H and a process for the production of a silicon-containing polymer having a main chain of oxygen atoms, organic groups and disubstituted silicon atoms are disclosed. The silicon-containing polymer may be produced by dehydrogenative polymerization of quinone and/or diol with trihydrosilane or dihydrosilane in the presence of a palladium-containing catalyst.

Abstract: A compound is provided including an organometallic complex represented by the formula I: [CpM(CO)2(NHC)Lk]+A−  I wherein M is an atom of molybdenum or tangsten, Cp is substituted or unsubstituted cyclopentadienyl radical represented by the formula [C5Q1Q2Q3Q4Q5], wherein Q1 to Q5 are independently selected from the group consisting of H radical, C1-20 hydrocarbyl radical, substituted hydrocarbyl radical, halogen radical, halogen-substituted hydrocarbyl radical, —OR, —C(O)R′, —CO2R′, —SiR′3 and —NR′R″, wherein R′ and R″ are independently selected from the group consisting of H radical, C1-20 hydrocarbyl radical, halogen radical, and halogen-substituted hydrocarbyl radical, wherein said Q1 to Q5 radicals are optionally linked to each other to form a stable bridging group, NHC is any N-heterocyclic carbene ligand, L is either any neutral electron donor ligand, wherein k is a number from 0 to 1 or L

Abstract: An apparatus for continuously preparing substantially halogen-free, in particular chlorine-free, trialkoxysilanes of the general formula I (RO)3SiH  (I) in which R is an alkyl group having from 1 to 6 carbon atoms, has a main reactor unit (1), at least one metering unit (2, 3, 4) for liquids and/or suspensions, located upstream of the main reactor, and at least one metering unit (5) for gaseous and/or vaporous substances, and also a product workup unit (6) located downstream of the main reactor. A process for preparing substantially halogen-free trialkoxysilanes of the general formula I in which silicon is reacted with alcohols in an inert solvent utilizes at least one organocopper compound catalyst.

Abstract: Process for the production of alkoxysilanes of the formula HSi(OR)3, where R is an alkyl group containing 1 to 6 carbon atoms, and/or alkyl orthosilicates of the formula Si(OR)4, where R is an alkyl group containing 1 to 6 carbon atoms. In a preferred embodiment, the process comprises reacting silicon metal with an alcohol in a suitable solvent in the presence of a cupric bis(diorganophosphate) catalyst. A polymeric form of ethyl orthosilicate, a by-product of the reaction, is the preferred solvent. The production of triethoxysilane and tetraethyl orthosilicate is preferred, with triethoxysilane being particularly preferred.

Abstract: Process for the production of alkoxysilanes of the formula HSi(OR)3, where R is an alkyl group containing 1 to 6 carbon atoms, and/or alkyl orthosilicates of the formula Si(OR)4, where R is an alkyl group containing 1 to 6 carbon atoms. In a preferred embodiment, the process comprises reacting silicon metal with an alcohol in a suitable solvent in the presence of a cupric bis(diorganophosphate) catalyst. A polymeric form of ethyl orthosilicate, a by-product of the reaction, is the preferred solvent. The production of triethoxysilane and tetraethyl orthosilicate is preferred, with triethoxysilane being particularly preferred.

Abstract: A process for preparing linear organohydrogensiloxanes. The process comprises contacting an organohydrogendichlorosilane in the presence of trimethylchlorosilane with water to form an M-stopped hydrolyzate. The hydrolyzate is optionally preheated prior to being contacted with an acidic rearrangement catalyst to effect formation of linear organohydrogensiloxanes. The linear organohydrogensiloxanes are separated from cyclic organohydrogensiloxanes and recovered. The cyclic organohydrogensiloxanes may then be recycled to the process for further contact with the acidic rearrangement catalyst for maximum overall conversion rate.

Abstract: A method for forming at least one product silane, comprising reacting a transition metal hydride with a starting silane in a presence of a catalyst and at a temperature that exceeds a threshold temperature associated with said reacting.

Abstract: In a process for preparing trialkoxysilanes by reaction of silicon metal with an alcohol in an inert solvent in the presence of a copper catalyst, the copper catalyst used is a copper salt whose anion contains at least one nonhydrolyzable fluorine atom, or a mixture thereof with other salts.

Abstract: The invention provides a process for producing an &agr;-hydroxy-carbonyl compound or an &agr;-protected hydroxy-carbonyl compound by reacting a carbonyl compound (I) with a compound (II) and a compound (III). The compounds (I), (II) and (III) are defined below. R1, R2, R3 and R4 are an organic group. PG is a protective group for hydroxy group. Y is R4N, S or O. The product is useful in pharmacology.

Abstract: Trialkoxysilanes are prepared by reacting silicon metal with an alcohol in an inert solvent in the presence of a copper catalyst by a process in which the copper catalyst contains copper(II) oxide having a BET surface area of ≧10 m2/g. Furthermore, this copper catalyst is used for the preparation of trialkoxysilanes by reacting silicon metal with an alcohol.

Abstract: A method for the preparation of tetraorganooxysilanes is provided which comprises reaction of a natural silicon dioxide source with an organo carbonate.

Abstract: A filler/adhesive agent for display units containing a condensation reaction curable silicone composition including air oxidation-curable unsaturated compounds and for use as a filler or adhesive in display units whose construction is such that the cured product of said composition is exposed in the display section, which composition is capable of forming matte finished cured products with insignificant surface tact, is disclosed.

Abstract: In an extraction process for isolating trimethoxysilane (TMS) from a TMS/methanol mixture by formation of two phases, namely a TMS-rich extract phase and a methanol-rich raffinate phase, by addition of one or more methanol-soluble inorganic and/or organic salts and, if desired, an additional nonpolar organic solvent and subsequent phase separation, the amount of salt added is selected so that the weight ratio of trimethoxysilane to methanol in the extract phase is at least 94% by weight:6% by weight (normalized to 100% by weight). The use of one or more inorganic salts in an extraction process for isolating trimethoxysilane from a trimethoxysilane/methanol mixture is also claimed.

Abstract: Alkoxysilanes are prepared by a process, comprising: (i) reacting a chlorosilane with an alcohol in a water-free and solvent free phase with removal of the liberated hydrogen chloride; (ii) transferring the resultant product mixture into a liquid phase to be distilled and adding a metal alcoholate to the product mixture in the liquid at a temperature in the range from 10-60° C., and thoroughly mixing the neutralized product mixture, said alcoholate being employed in an equimolar amount or in a stoichiometric excess based on the amount of acidic chloride, and (iii) purifying the treated product mixture by distillation under reduced pressure, thereby preparing alkoxysilanes which are low in acidic chloride or essentially free of acidic chloride.

Abstract: A hydroxyl group-containing compound is silylated by reacting it with an organohydrosilane compound in the presence of a ruthenium complex catalyst having carbonyl groups as ligands. Silylation takes place in a short time while the amount of the catalyst is minimized.

Abstract: A process for the production of optically active Si compounds by reacting a meso-epoxide with a azidotrimethylsilane and a hydrocarbyl halide in the presence of a catalyst formed from the sequential treatment of hafnium t-butoxide or zirconium t-butoxide with one equivalent of homochiral optically active triisopropanolamine, water, and a source of trifluoroacetae ion is disclosed.

Abstract: The invention relates to organopolysiloxanes that have amino groups and are solid at room temperature which can reversibly change their states of aggregation on the basis of temperature changes. Preparations containing these organopolysiloxanes are useful in the cleaning, care, and hydrophobicization of surfaces.

Abstract: Chlorine-free tetraalkoxysilanes of formula (I) (R1O)4Si  (I) wherein R1 is, independently in each instance, an unbranched, branched, and/or cyclic C1-6 hydrocarbon group is continuously manufactured by a process, comprising: reacting metallic silicon powder with a monohydric alcohol in the presence of a basic catalyst comprising a mixture of: (a) at least one compound of formula (II) [R2O—(R3O)m]nSi)OR1)4-n  (II) (b) at least one compound of formula (III) R2O—(R3O)m—M, and  (III) (c) at least one compound of formula (IV) R2O—(R3O)m—H  (IV) wherein R1 is as defined above; R2 represents, independently in each instance, a C1-10 hydrocarbon group, or hydrogen; R3 represents, independently in each instance, a C1-4 hydrocarbon group; M represents an alkali metal selected from the group consisting of Li, Na, and K; m is zero or a number in the range of 1-20; and n is zero or a number in the range of 1-4; further comprisin

Abstract: Dissolved silanes, silicones and silicates from solvents used in the slurry phase Direct Synthesis of alkoxysilanes are removed by adding a compatabilizing agent and water to generate filterable precipitates and reusable solvent. The solvents are thereby remediated and made suitable for reuse in Direct Synthesis processes. Foaming is reduced with the remediated solvent and silicon conversion rates are higher. The precipitates are easily filtered and retain negligible quantities of solvent.

Abstract: The following class of glycidyl and allyl ethers are found to cure at room temperature much faster than their glycidyl and allyl analogs: ##STR1## where: R.sub.1 is selected from the group consisting of:(a) an aliphatic hydrocarbon group containing 2 to 10 carbon atoms; and(b) a group having the formula ##STR2## wherein n=1 to 3,m=0 to 5R.sub.2 and R.sub.2 ' are each selected from the group consisting of an alkyl group containing 1 to 4 carbon atoms, an unsubstituted aryl group, and a substituted aryl group, and R.sub.

Abstract: Dissolved silanes, silicones and silicates from solvents used in the slurry phase Direct Synthesis of alkoxysilanes are removed by adding a carboxylic acid such as formic acid to generate filterable precipitates and reusable solvent. The solvents are thereby remediated and made suitable for reuse in Direct Synthesis processes. Foaming is reduced with the remediated solvent and silicon conversion rates are higher. The precipitates are easily filtered and retain negligible quantities of solvent.

Abstract: Higher alkoxysilanes are prepared efficiently and in high yield by transesterification of lower C.sub.1-4 alkoxysilanes with C.sub.6-38 higher alcohols at reduced pressure with continuous removal of lower alcohol. The products have little or no lower alkoxy content, and are free of coloring impurities.

Abstract: A composition containing an organic material subject to oxidative, thermal or actinic degradation can be stabilized by an effective amount of at least one polysilane compound of formula I ##STR1## Preferred compounds are where q is zero, p is 2 to 50, m is zero, R.sub.1 is alkyl, phenyl or benzyl, and A and B are independently hydrogen or a group --Si(E).sub.3 where E is alkyl. These compounds can also be copolymeric having a random, alternate or block distribution of individual structural units. These compounds are particularly suitable as process stabilizers.

Abstract: A method for forming alkyl silicate easily at low costs. The method comprises a reaction step of mixing and reacting an aqueous solution of sodium silicate, and a solution of alcohol or alkyl halide in a water-insoluble organic solvent, in the presence of a catalyst; and an isolating step of separating an organic layer from the reactive mixed solution and isolating a reaction product from the organic layer.

Abstract: A method of hydrolyzing an alkoxysilane which comprises adding sufficient water to hydrolyze at least one alkoxy group, optionally, in the presence of acidic or basic catalysts.

Abstract: The invention provides high purity alkoxytrimethylsilane fluids of the general formula ROSiMe.sub.3 wherein Me is methyl and R is a monovalent aliphatic hydrocarbon substituent which ranges from 14 to about 20 carbons, the fluid being substantially free of organic and inorganic contaminants, wherein the alkoxytrimethylsilanes are produced by a novel process, and can be readily incorporated into cosmetic formulations containing organic components without heating and provide improved sensory characteristics compared to those provided by the corresponding alcohols.

Abstract: A process for the preparation of hydrocarbon solutions of monofunctional ether initiators of the following general structure:M--Q.sub.n --Z--OA(R.sup.1 R.sup.2 R.sup.3)wherein M is defined as an alkali metal, selected from the group consisting of lithium, sodium and potassium, Q is an aromatic substituted saturated hydrocarbyl group produced by the incorporation of one or more alkenyl substituted aromatic hydrocarbons containing 8-25 carbon atoms into the M--Z linkage; Z is a branched or straight chain hydrocarbon group which contains 3-25 carbon atoms, optionally containing aryl or substituted aryl groups; A is an element selected from carbon and silicon; R.sup.1, R.sup.2, and R.sup.

Abstract: The present invention relates to a novel process for preparing cis-4-O-protected-substituted-2-cyclopentenol derivatives comprising, a) dissolving a 4-O-protected-2-cyclopentenone in a suitable organic solvent; and b) treating the solution with a suitable Lewis acid and a suitable reducing agent at a temperature of from about -100.degree. C. to about 20.degree. C. The cis-4-O-protected-substituted-2-cyclopentenol derivatives are useful intermediates in the preparation of various cyclopentanyl and cyclopentenyl purine analogs which are useful as immunosuppressants and in the preparation of various prostaglandins.

Abstract: Disclosed is a process in which surface-active additives are used in the slurry phase Direct Synthesis of trialkoxysilanes to shorten the period between the start of the reaction and the attainment of steady-state rates and selectivities, to improve product yields and to control or prevent foam formation. Compositions comprising silicone antifoam compounds and fluorosilicone polymers are the preferred surface-active additives of the instant process.

Abstract: The present invention relates to a novel process for preparing cis-4-O-protected-substituted-2-cyclopentenol derivatives comprising, a) dissolving a 4-O-protected-2-cyclopentenone in a suitable organic solvent; and b) treating the solution with a suitable Lewis acid and a suitable reducing agent at a temperature of from about -100.degree. C. to about 20.degree. C. The cis-4-O-protected-substituted-2-cyclopentenol derivatives are useful intermediates in the preparation of various cyclopentanyl and cyclopentenyl purine analogs which are useful as immunosuppressants and in the preparation of various prostaglandins.

Abstract: Disclosed is an improved process for the slurry phase Direct Synthesis of trialkoxysilanes which comprises the activation of copper catalyst and silicon with a reducing agent such as hydrogen gas, carbon monoxide or monosilane. Such activation affords high, stable reaction rates and selectivities and high silicon overall conversion especially in alkylated benzene solvents.

Abstract: A process for the preparation of hydrocarbon solutions of monofunctional ether initiators of the following general structure:M--Q.sub.n --Z--OA(R.sup.1 R.sup.2 R.sup.3)wherein M is defined as an alkali metal, selected from the group consisting of lithium, sodium and potassium, Q is a saturated or unsaturated hydrocarbyl group derived by incorporation of a compound selected from the group consisting of conjugated diene hydrocarbons and alkenylsubstituted aromatic hydrocarbons; Z is a branched or straight chain hydrocarbon group which contains 3-25 carbon atoms, optionally containing aryl or substituted aryl groups; A is an element selected from carbon and silicon; R.sup.1, R.sup.2, and R.sup.

Abstract: A chemiluminescent 1,2-dioxetane derivative having a formula (I): ##STR1## wherein R.sup.1 and R.sup.4 each represent, individually, hydrogen, an alkyl group, an alkoxyl group, a hydroxyl group, or --OSi(R.sup.9 R.sup.10 R.sup.11) in which R.sup.9, R.sup.10 and R.sup.11 each represent an alkyl group; R.sup.2, R.sup.3, R.sup.5 and R.sup.6 each represent, individually, hydrogen or an alkyl group, provided that R.sup.2, R.sup.3, R.sup.5 and R.sup.6 each cannot be hydrogen at the same time, and that R.sup.2 and R.sup.3, and R.sup.5 and R.sup.6, each taken together, can form a cycloalkyl group; R.sup.7 represents an alkyl group; R.sup.8 represents hydrogen, an alkoxyl group, a phosphate salt group, or --OSi(R.sup.9 R.sup.10 R.sup.11); intermediates for synthesizing the above 1,2-dioxetane derivative; and methods of producing the intermediates are provided.

Abstract: A coating composition comprising:a hydrolyzed or partially hydrolyzed alkoxysilane,a solvent,and an arylcyclobutene;is useful in a variety of applications, including coatings for multichip modules, flat panel displays and integrated circuits. The preferred alkoxysilanes correspond to the formula: ##STR1## wherein R is C.sub.1 -C.sub.6 alkylidene, C.sub.1 -C.sub.6 alkylene, arylene, or a direct bond; Y is C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, aryl, 3-methacryloxy, 3-acryloxy, 3-aminoethylamino, or 3-amino; R' is independently in each occurrence C.sub.1 -C.sub.6 alkyl; and Z is C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl or OR'.

Abstract: A process for preparing functionalized alkyllithium compounds includes reacting in an inert solvent a protected functionalized alkyl halide with an alkali metal in the presence of a catalytic compound of the formula(RR.sup.1 R.sup.2 M.sup.a).sub.y A(R.sup.3).sub.xwherein R, R.sup.1 and R.sup.2 are each independently selected from the group consisting of hydrogen, halogen, alkyl or alkenyl groups containing one to thirteen carbon atoms; R.sup.3 is independently selected from aryl groups containing 6 to 18 carbon atoms, four to six-membered heterocyclic carbon containing groups containing one to two heteroatoms selected from oxygen, nitrogen and sulfur; hydroxyalkyl, alkoxyalkyl, monoalkylaminoalkyl, dialkylaminoalkyl and dialkylphosphinoalkyl groups containing two to thirteen carbon atoms; M.sup.

Abstract: A process for the preparation of hydrocarbon solutions of monofunctional ether initiators of the following general structure:M--Q.sub.n --Z--OA(R.sup.1 R.sup.2 R.sup.3) (II)wherein M is defined as an alkali metal, selected from the group consisting of lithium, sodium and potassium, Q is a saturated or unsaturated hydrocarbyl group derived by incorporation of a compound selected from the group consisting of conjugated diene hydrocarbons and alkenylsubstituted aromatic hydrocarbons; Z is defined as a branched or straight chain hydrocarbon tether or connecting group which contains 3-25 carbon atoms, optionally containing aryl or substituted aryl groups; A is an element selected from Group IVa of the periodic table and R.sup.1, R.sup.2, and R.sup.3 are independently selected from hydrogen, alkyl, substituted alkyl, aryl or substituted aryl groups, and n is an integer from 1 to 5.

Abstract: The invention concerns a process of preparing silicone monomer products comprising a reaction between alkylchloro silane and an aliphatic ether in the presence of a catalyst to form the corresponding alkoxyalkyl silane silicone monomer product and alkyl chloride that are subsequently separated.

Abstract: A method for hydrosilylating an olefinically unsaturated compound comprising contacting the unsaturated compound with a source of silicon in the presence of an azo-containing free-radical catalyst, the hydrosilylated product being a useful crosslinking agent.

Abstract: Hydrogenalkoxysilanes are prepared by direct reaction of finely divided metallic silicon with alcohols in the presence of copper-containing catalysts in a heat-transfer oil comprising tritoluenes, tetratoluenes or mixtures thereof at from 100.degree. to 350.degree. C.

Abstract: Vinyl- and alkoxy-functional organosilicon compounds with the general formula ##STR1## in which R denotes C.sub.1 and C.sub.4 alkyl and a is 1, 2, or 3, b is 0 or 1, and a+b is 2 or 3 are made by an exchange reaction between sym-divinyltetramethyldisiloxane and vinyltrialkoxysilane or tetraalkoxysilane. These novel vinyl- and alkoxy-functional organosilicon compounds exhibit a high condensation reactivity with the silanol group.

Abstract: Processes for preparing 2,2-difluoroketene silyl O,S-acetals and .alpha.,.alpha.-difluoro-.beta.-silyloxy-1,3-dioxolane-4-propanoic acid O,S-esters.

Abstract: A novel coating for glass with an adhesive strength of >45 Kg/cm.sup.2 and improved resistance to moisture and sunlight, which may contain opacifying pigments for decorating glass surfaces, is a hard (Shore D 84), crosslinked siloxane-urea, siloxane-urethane, siloxane-sulfide or siloxane-amide which adheres covalently to the glass surface and is resistant to scratching and delamination.

Abstract: Benzoic acid derivatives represented by the formula (I): ##STR1## wherein R.sub.1 represents hydrogen or lower-alkyl, R.sub.2 and R.sub.4 represent hydrogen, trimethylsilyl, or trimethylgermyl, R.sub.3 represents hydrogen, lower-alkyl, trimethylsilyl, or trimethylgermyl, R.sub.5 represents hydrogen, lower-alkyl, acetyl, or hydroxy, at least one of R.sub.2 and R.sub.3 being trimethylsilyl or trinethylgermyl, and R.sub.6 means hydroxy, lower-alkoxy, or a group of the formula --NR.sub.7 R.sub.8, wherein R.sub.7 and R.sub.8 mean hydrogen or lower-alkyl, and X represents a group of the formula --CONH--, --NHCO--, --COO--, --OCO--, --COCH.dbd.CH--, --COCH.dbd.C(OH), or --CH.dbd.CH--, which exhibit excellent effect as differentiation-inducing agents for neoplastic cells, especially leukemia cells, or a therapeutic agent for psoriasis or immune and inflammatory diseases, and a process for the preparation thereof, are disclosed.