Preparation of 1,4-diketopyrrolo-[3,4-c]pyrroles

Claim 1

A process for the preparation of a 1,4-diketopyrrolo-[3,4-c]pyrrole of the formula ##STR14## wherein each of R 1 and R 2 independently of the other is phenyl of said phenyl substituted by one or two fluorine, chlorine or bromine atoms or mixtures thereof, by one, two or three methoxy or methyl groups or mixtures thereof with chlorine atoms, by cyano, by dimethylamino, by trifluoromethyl, by alkoxycarbonyl of 2 to 3 carbon atoms, by tert-butyl, by cyanophenyl, by acetyl or by alkylbenzoyloxy of 11-14 carbon atoms; biphenylyl; naphthyl or said naphthyl substituted by methoxy; anthryl; phenanthryl; pyridyl or said pyridyl substituted by methyl or by amyloxy; quinolyl; furyl or thienyl, which consists essentially of reacting 1 mole of the compound of the formula ##STR15## wherein M is a metal atom, Z is alkyl or aryl, X is halogen or acetate, and m is a value from 0 to 2, with 1 mole of a compound of the formula YCH.sub.2 COOZ (III) wherein Y is halogen, and with 1 mole of a nitrile of the formula R.sub.1 --CN (IV) or R.sub.2 --CN (V) in an organic solvent and at elevated temperature of 60°-160° C., and isolating the compound of formula I.