摘要:
A process for preparing trans-chrysanthemic acid which comprises reacting a mixture of alkyl trans-chrysanthemate and alkyl cis-chrysanthemate with an equimolar amount or less of an alkali with respect to the trans-isomer in the presence of water or an alcohol to hydrolyze the trans-isomer predominantly and separating the hydrolyzed trans-isomer from the unreacted cis-isomer.
摘要:
Alkyl cis-chrysanthemate is treated with a catalytic amount of alkali metal alkoxide at a temperature of about 50.degree. to 200.degree.C in the absence or presence of an aprotic solvent to give alkyl trans-chrysanthemate in a high purity and an excellent yield.
摘要:
A process for producing furan derivatives of the formula, ##STR1## wherein R is hydrogen, methyl or chloromethyl, which comprises reacting a mono- or a disaccharide with hydrochloric acid in a mixture containing water, an organic solvent and a catalytic amount of a surface active agent.
摘要:
A method for racemization of optically active amines which comprises contacting an optically active amine of the formula: ##EQU1## wherein C* is an asymmetric carbon atom, R.sub.1 is alkyl, aralkyl or aryl and R.sub.2 is aryl or alkoxycarbonyl, the aryl or aralkyl moiety bearing optionally one or more alkyl or alkoxy groups on the aromatic ring, provided that R.sub.1 and R.sub.2 are always different from each other, with an alkali metal catalyst selected from the group consisting of (1) an alkali metal deposited on a solid carrier, (2) an alkali metal dispersed in a liquid medium and (3) an alkali metal alloy at a temperature of from -10.degree. to 50.degree.C until a sufficient amount of the optically active amine is recemized.
摘要:
A method for racemization of optically active amines which comprises contacting an optically active amine of the formula: ##STR1## wherein C* is an asymmetric carbon atom, R.sub.1 is alkyl, aralkyl or aryl and R.sub.2 is aryl or alkoxycarbonyl, the aryl or aralkyl moiety bearing optionally one or more alkyl or alkoxy groups on the aromatic ring, provided that R.sub.1 and R.sub.2 are always different from each other, with a catalyst comprising an alkali metal and a polycyclic aromatic hydrocarbon until a sufficient amount of the optically active amine is racemized.
摘要:
A method for racemization of optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acids of the formula: ##EQU1## wherein R.sub.1 and R.sub.2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms, which comprises the step of contacting the corresponding acid halide with a Lewis acid.
摘要:
A method for racemization of optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acids of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms, which comprises the step of contacting the corresponding acid halide with boron halide at a temperature of not more than 20.degree. C.
摘要:
A method for racemization of optically active amines which comprises contacting an optically active amine of the formula: ##STR1## wherein C* is an asymmetric carbon atom, R.sub.1 is alkyl, aralkyl or aryl and R.sub.2 is aryl or alkoxycarbonyl, the aryl or aralkyl moiety bearing optionally one or more alkyl or alkoxy groups on the aromatic ring, provided that R.sub.1 and R.sub.2 are always different from each other, with a catalyst comprising an alkali metal and a polycyclic aromatic hydrocarbon until a sufficient amount of the optically active amine is racemized.
摘要:
Rose oxide, which is an important olfactive compound valuable in the art of perfumery, is advantageously produced from citronellol through a novel synthetic route comprising(1) anodic alkoxylation of citronellol using as a supporting electrolyte an alkali metal aromatic sulfonate,(2) dealkoxylation of the resulting 2,6-dimethyl-3-alkoxyoct-1-en-8-ol in the presence of a palladium or nickel complex, and then(3) cyclization of the resulting dehydrocitronellol in the presence of an acid.
摘要:
A novel optically active cis-4,5-disubstituted imidazolidin-2-one derivative of the formula: ##STR1## wherein R.sup.1 is a C.sub.1 -C.sub.4 alkyl group or benzyl and R.sup.2 is a chiral aralkyl group optionally having at least one of C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy and hydroxyl groups is produced asymmetrically by the reaction of 1,3-dibenzyl-cis-4,5-dicarboxy-imidazolidin-2-one or its anhydride with an optically active secondary amine of the formula: ##STR2## wherein R.sup.1 and R.sup.2 are each as defined above and is transformed into the lactone of 1,3-dibenzyl-cis-4-carboxy-5-hydroxymethyl-imidazolidin-2-one, which is a key intermediate in the synthesis of d-biotin.