Process for preparation of asymmetric isoindoline pigments

This invention relates to a process for preparing asymmetric isoindoline pigments of the formula in which R1 is an electron-withdrawing group, R2 and R3 are independently hydrogen, alkyl, or aryl, and R4, R5, R6, and R7 are independently hydrogen, halogen, alkyl, alkoxy, or aryloxy. The process employs an initial reaction of a 1,2-dicyanobenzene with an alcohol in an organic medium in the presence of a base. The resultant imino-isoindoline intermediate composition reacts without isolation with a cyanomethylene compound NC-CH2-R1 to form a partly condensed product that is then condensed without isolation in the presence of water with barbituric acid or a derivative thereof to form the asymmetric isoindoline pigment.