P-Phenylenediamine → (2Z)-4-[(4-Aminophenyl)amino]-4-oxo-2-butenoic acid

Participants

Reaction Steps

Under a nitrogen atmosphere, into a reaction vessel were charged 13.0 g (0.12 mol) of 1,4-phenylenediamine and 140 ml of tetrahydrofuran. A solution prepared by dissolving 11.77 g (0.12 mol) of maleic anhydride in 25 ml of tetrahydrofuran was dropped into this under cooling with ice over a period of about 1 hour, then, the mixture was stirred at room temperature overnight. After completion of the reaction, the deposited crystal was isolated by filtration, and dried to obtain 24.20 g of coarse (2Z)-4-[(4-aminophenyl)amino]-4-oxo-2-butenoic acid as an orange powder. To 24.2 g of coarse (2Z)-4-[(4-aminophenyl)amino]-4-oxo-2-butenoic acid were added 250 ml of tetrahydrofuran and 50 ml of water, and the mixture was stirred at room temperature for 2 hours, then, isolated by filtration, and the filtrated material was washed twice with 20 ml of 50% tetrahydrofuran water. The resultant crystal was dried at 40° C. for 5 hours, to obtain 21.96 g of (2Z)-4-[(4-aminophenyl)amino]-4-oxo-2-butenoic acid mono-hydrate as a yellow-orange powder. Yield: 81.5%.

Provenance & Evidence