PURPOSE: To extremely efficiently obtain the corresponding trans-chrysanthe mum-monocarboyxlic acids useful as a raw material for pyrethroid based insecticides under mild condition, by reacting mixed cis- or cis/tans- chrysanthemum-monocarboxylic acids with a phosphorus bromide compound in the presence of a peroxide.
CONSTITUTION: Mixed cis- or cis/trans-chrysanthemum-monocarboxylic acids expressed by the formula (R is H or 1W20C alkyl, cycloalkyl or aralkyl)are reacted and converted into the trans-isomer with a phosphorus bromide compound, such as phosphorus tribromide, phosphorus pentabromide and/or phosphorus oxytribromide, in the presence of a peroxide, preferably hydroperoxides, diacyl peroxides or peroxy esters, particularly hydroperoxides, normally at -20W+100°C temperature to industrially and advantageously afford the corresponding trans-chrysanthemum-monocarboxylic acids having more powerful insecticidal efficacies than those of the cis-isomer using the phosphorus bromide compound which is more common as the industrial raw material.
FUKAO MASAMI
SAKITO YOJI
JPS63196541A | 1988-08-15 |
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