FREMGANGSMAADE TIL FREMSTILLING AF 1,4-DIKETOPYRROLO-(3,4-C)-PYRROLER

摘要

A process for the preparation of 1,4-diketopyrrolo-[3,4-c]pyrroles of the formula (I) wherein each of R1 and R2 independently of the other is an isocyclic or heterocyclic aromatic radical, which process comprises reacting 1 mole of a disuccinate with 2 moles of a nitrile of the formula R1-CN (II) or R2-CN (III) or with 1 mole of a nitrile of the formula (II) and 1 mole of the nitrile of the formula (III), in an organic solvent and in the presence of a strong base at elevated temperature, and obtaining the compound of formula I from the reaction product by hydrolysis. The pyrrolo-[3,4-c]pyrroles are suitable for pigmenting organic material of high molecular weight.