反应详情

A solution of 16 parts of ethyl toluene-4-sulfonate in 15 parts of dimethylformamide is added to a mixture, warmed to 140°-142° C., of 5.8 parts of 1,4-diketo-3,6-diphenylpyrrolo-[3,4-c]-pyrrole, 12.2 parts of potassium carbonate and 60 parts of dimethylformamide in the course of 30 minutes, with stirring. The brown-yellow solution formed is subsequently stirred at 142° C. for 5 minutes, and 100 parts of methanol are added at 70° C. The yellow precipitate which has separated out is filtered off at 15° C., washed with methanol and with hot water at 90° C. and dried. The crude product (3.6 parts) is recrystallised first from 40 part of dimethylformamide and then from 100 parts of n-butanol. 2.8 parts of 1,4-diketo-2,5-diethyl-3,6-diphenylpyrrolo-[3,4-c]-pyrrole of the following formula are obtained in the form of orange-yellow needles of melting point 229°-230° C.: ##STR32##

1. customThe brown-yellow solution formed
2. stirringis subsequently stirred at 142° C. for 5 minutes
3. customThe yellow precipitate which has separated out
4. filtrationis filtered off at 15° C.
5. washwashed with methanol and with hot water at 90° C.
6. customdried
7. customThe crude product (3.6 parts) is recrystallised first from 40 part of dimethylformamide