Method for racemization of optically active chrysanthemic acid or its ester
AssigneeSumitomo Chemical Company, Limited
InventorsGohfu Suzukamo, Yoji Sakito, Masami Fukao, Koji Hagiya
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Abstract
Racemization of optically active chrysanthemic acid or its ester of the formula: ##STR1## wherein R represents a hydrogen atom or an alkyl, cycloalkyl or aralkyl group of 1-20 carbon atoms and * indicates an asymmetric carbon atom, is effected by contacting it with hydrogen bromide or a phosphorus bromide compound. This method may also be effected in the presence of a peroxide or an azo compound. This method is industrially very useful.
Claims30
A method for the racemization of optically active chrysanthemic acid or its ester of the formula:
- ##STR3## wherein R represents a hydrogen atom, an alkyl group of 1-20 carbon atoms, a cycloalkyl group of 3-20 carbon atoms or an aralkyl group of 7-20 carbon atoms and * mark represents an asymmetric carbon atom, which comprises contacting the acid or its ester with hydrogen bromide or a phosphorus bromide compound.
A method for conversion of cis isomer or of a mixture of cis and trans isomers of chrysanthemic acid or its ester of the formula:
- ##STR4## wherein R represents a hydrogen atom, an alkyl group of 1-20 carbon atoms, a cycloalkyl group of 3-20 carbon atoms or an aralkyl group of 7-20 carbon atoms, to the corresponding trans-rich chrysanthemic acid or its ester, which comprises contacting the acid or its ester described above with hydrogen bromide or a phosphorus bromide compound.
Dependencies are inferred from the claim text.