Preparation of 3,3-dimethyl-cyclopropane-1,1,2-tricarboxylic acid derivatives and intermediates therefor

Abstract

3,3-Dimethyl-cyclopropane-1,1,2-tricarboxylic acid derivatives of the formula ##STR1## in which R is alkyl, and R.sup.1 and R.sup.2 each is alkoxycarbonyl or cyano, with the proviso that at least one of them is cyano, suitable for use as intermediates in making insecticides, are produced by reacting a .beta.,.beta.-dimethyl-acrylic acid nitrile of the formula ##STR2## with bromine or chlorine at a temperature between about -20.degree. and +50.degree. C. to produce a compound of the formula ##STR3## in which Hal is chlorine or bromine, which compound is further reacted with a malonic acid derivative of the formula ##STR4##

Dependencies are inferred from the claim text.