(Chlorinated) trichloromethoxy benzoyl chlorides prepn - by free-radical catalysed chlorination of methoxy benzoates

摘要

Title cpds. of formula (I): (one of X1 and X2 = CCl3O other is H or Cl; X3 = H or Cl) are prepd. from cpds. of formula (II): (one of Y1 and Y2 = MeO, other is H or Cl, X3 = H or Cl) by chlorinating in presence of a diluent at 80-220 degrees C with simultaneous introduction of (II), gaseous Cl2 and a free radical catalyst into the diluent. Pref. catalyst is dibenzoyl peroxide or AZBN; solvent is preformed (I); temp. is 120-170 degrees C and (II) are the 3-MeO, 4-MeO or 3-Cl-4-MeO esters. (I) are intermediates for urea-type herbicides and are obtained in a single stage in high yield without ring chlorination.