Carbazole dioxazine pigments

摘要

The present disclosure relates to a benzoyl substituted carbazole-dioxazine pigment and its preparation. The process involves benzoylation of 3-nitro-N-ethylcarbazole in monochlorobenzene using benzoylchloride and ferric chloride to yield 3-nitro-6-benzoyl-N-ethyl carbazole, which on catalytic hydrogenation and subsequent condensation with chloranil and cyclization yields benzoyl substituted carbazole-dioxazine pigment.

主权项

1. A process for the synthesis of a carbazole-dioxazine pigment of Formula I; wherein, R is C1-C8 alkyl group, R1 is a chloro group, and R2 is a benzoyl group, said process comprising the following steps: a) reacting 3-nitro-N-ethyl carbazole with benzoylchloride in the presence of monochlorobenzene and ferric chloride to obtain 3-nitro-6-benzoyl-9N-ethyl carbazole; b) hydrogenating said 3-nitro-6-benzoyl-9N-ethyl carbazole in a solvent in the presence of Raney nickel catalyst and sodium phosphate dibasic to obtain 6-benzoyl-3-amino-9N-ethyl carbazole; c) condensing 6-benzoyl-3-amino-9N-ethyl carbazole with chloranil in the presence of a solvent and sodium acetate to obtain an intermediate of formula II; and wherein, R is C1-C8 alkyl group, R1 is a chloro group, and R2 is a benzoyl group, d) cyclizing the intermediate using a cyclizing agent to obtain carbazole-dioxazine pigment of formula I.