Potassium Hydroxide → Perylene-3,4-dicarboxylic acid

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Reaction Steps

At a yield of 50% in the reaction in the autoclave, monoimide 2b is a suitable starting material for preparing perylene-3,4-dicarboxylic anhydride 4. To this end, 2b is reacted, for example, with KOH in tert-butyl alcohol, followed by hydrolysis to give the monoamide of perylene-3,4-dicarboxylic acid. Acidification of the alkaline solution of the monoamide thus obtained results in further hydrolysis of a portion thereof to give the desired perylene-3,4-dicarboxylic anhydride (4) (while the other portion reverts to the starting material 2b). A particularly suitable acid is 50 per cent acetic acid, which gives yields of more than 60% of 4; based on conversion, the isolated yield of 4 is even more than 90%. The remaining portion of the cyclization product 2b can be separated off without any difficulty by dissolution with hot potassium carbonate solution, filtration and precipitation with acetic acid, so that the anhydride 4 is obtained in high purity.

Provenance & Evidence