Patent ID: 7186847

Claim:
A process for the direct preparation of a 1,4-diketopyrrolo[3,4-c]pyrrole of the formula wherein R 1 and R 2 independently of each other are an unsubstituted or substituted isocyclic or heterocyclic aromatic radical, which process comprises (a) heating an appropriate molar ratio of a disuccinate with a nitrile of the formula (II) R 1 —CN (II) or of the formula (III) R 2 —CN (III) or with mixtures of said nitriles, in an organic solvent and in the presence of a strong base, to form an intermediate condensation product, (b) conditioning of the intermediate condensation product obtained in step (a) in water or a mixture of water and a water-miscible solvent, optionally in the presence of an inorganic acid, to form the compund of formula (I) and (c) optionally conditioning of the product obtained in step (b) in an aprotic solvent, characterized in that a nitrile compound of the formula wherein R 40 , R 41 and R 42 are independently of each other hydrogen, linear or branched C 1-10 -alkyl, C 1-10 -alkoxy or C 1-10 -thioalkyl, C 5-10 -cycloalkyl, C 6-10 -aryloxy, C 6-10 arylthio, C 7-10 -aralkyloxy, C 7-10 -aralkylthio, halogen, CN, CONR 5 R 6 , C(O)OR 7 or SO 2 R 9 ; is added at the beginning of the synthesis, wherein a particle growth regulator of the formula is obtained, wherein R 1 , R 2 , R 40 , R 41 and R 42 are ad defined above, or a particle growth regulator is added in the heating step (a), the conditioning step (b) or (c), wherein said particle growth regulator is a compound of the formula wherein X is O, S or NR 14 , wherein R 14 is linear or branched C 1-10 -alkyl, C 7-10 -aralkyl or C 6-10 -aryl; R 12 and R 13 are independently of each other hydrogen, linear or branched C 1-10 -alkyl, C 1-10 -alkoxy or C 1-10 -thioalkyl, C 5-10 -cycloalkyl, C 6-10- -aryloxy, C 6-10 -arylthio, C 7-10 -aralkyloxy, C 7-10 -aralkylthio, halogen, CN, CONR 5 R 6 , C(O)OR 7 , SO 2 R 9 ; or a compound of the formula wherein R 15 and R 16 are independently of each other hydrogen, linear or branched C 1-10 -alkyl, C 1-10 -alkoxy, or C 1-10 -thioalkyl, C 5-10 -cycloalkyl, C 6-10 -aryloxy, C 6-10 arylthio, C 7-10 -aralkyloxy, C 7-10 -aralkylthio, halogen, CN, CONR 5 R 6 , C(O)OR 7 , SO 2 R 9 , wherein R 5 and R 6 are hydrogen, linear or branched C 1-10 -alkyl, C 5-10 -cycloalkyl or C 6-10 -aryl, R 7 is hydrogen, linear or branched C 1-10 -alkyl, C 5-10 -cycloalkyl, C 7-10 -aralkyl or C 6-10 -aryl, R 9 is hydrogen, linear or branched C 1-10 -alkyl, C 5-10 -cycloalkyl, C 7-10 -aralkyl, C 6-10 -aryl or NR 10 R 11 , wherein R 10 and R 11 are hydrogen, linear or branched C 1-10 -alkyl, C 1-10 -alkyl, C 7-10 -aralkyl or C 6-10 -aryl.