PROCESS FOR THE PREPARATION OF 1,3-DIBROMO-2,2-DIMETHYL-PROPANE-1,3-DICARBOXYLIC ACID DERIVATIVES,AND 1,3-DIBROMO-2,2-DIMETHYL-PROPANE-1,3-DICARBOXYLIC ACID DICHLORIDE AND CHLORIDE ESTERS AS NEW INTERMEDIATE

摘要

In the preparation of a 1,3-dibromo-2,2-dimethyl-propane-1,3- dicarboxylic acid derivative of the formula ##STR1## in which R.sup.1 and R.sup.2 each independently is chlorine or alkoxy, by reacting a 2,2- dimethyl-propane-1,3-dicarboxylic acid derivative of the formula ##STR2## in which R.sup.3 is hydroxy or alkoxy andPPR.sup.4 is hydroxy, orPPR.sup.3 and R.sup.4 together are an anhydride oxygen atom,PPwith an acid halide, then reacting the product with bromine at a temperature between 0 and 150 C. to form a 1,3-dibromo-2,2-dimethyl-propane-1,3- dicarboxylic acid chloride and optionally reacting such acid chloride with an alkanol, the improvement which comprises employing an acid chloride as the acid halide, e.g. phosphorus pentachloride, phosphorus oxychloride, phosphorus trichloride, thionyl chloride or phosgene. Compounds of the formula ##STR3## are new. The products are intermediates for making insecticides.