| 摘要 |
PURPOSE:To efficiently convert cis-chrysanthemum-monocarboxylic acid into the trans-isomer under mold condition in a short time and obtain the titled compound useful as a raw material for pyrethroid based insecticides in high yield, by reacting the cis-chrystanthemum-monmocarboxlic acid with al bromide, etc., using a catalytic amount of an azo compound. CONSTITUTION:cis- or Mixed cis-/trans-chrystanthemum-monocarboxylic acid expressed by the formula (R is H, 1-20C alkyl, cycloalkyl or aralkyl) is reacted with Al bromide, e.g. AlBr3, or boron bromide, e.g. BBr3, etc., in the presence of a catalytic amount of an azo compound, e.g. azobisisobutyronitrile, etc., preferably in an inert solvent at 0-100 deg.C for several min - 7hr to carry out conversion into the trans-isomer and afford the aimed compound. The conversion of the cis-chrysanthemum-monocarboxylic acid into the trans-isomer can be readily carried out and this method is advantageous to indistrial production of the trans-crystanthemum-monocarboxylic acid. The resultant compound is used as a raw material for pyrethroid based insecticides, e.g. pyrethrin, allethrin, phthalthrin, etc. |
