P-Phenylenediamine → HCID 86708822, compound

Under a nitrogen atmosphere, into a reaction vessel were charged 13.23 g (122.4 mmol) of 1,4-phenylenediamine and 225 ml of tetrahydrofuran. A solution prepared by dissolving 8.00 g (81.6 mmol) of maleic anhydride in 24 ml tetrahydrofuran was dropped into this under cooling with ice over a period of 2 hours, then, the mixture was stirred at room temperature for 3 hours. After completion of the reaction, 17.99 g (81.6 mmol) of a 25% potassium hydroxide aqueous solution was dropped under cooling with ice over a period of 30 minutes, and the mixture was stirred at room temperature for 2 hours. Thereafter, the solvent was distilled off under reduced pressure to obtain a residue to which 200 ml of tetrahydrofuran was added, and the mixture was stirred at 40° C. for 1 hour. After cooling to room temperature, the deposited solid was isolated by filtration, and washed with 50 ml of tetrahydrofuran. The resultant solid was dried under reduced pressure at 50° C. for 5 hours, to obtain 19.79 g of potassium (2Z)-4-[(4-aminophenyl)amino]-4-oxo-2-butenoate mono-hydrate as a red-brown solid. Yield: 92.5%

1. customA solution prepared
2. additionwas dropped into
3. temperaturethis under cooling with ice over a period of 2 hours
4. additionwas dropped
5. temperatureunder cooling with ice over a period of 30 minutes
6. stirringthe mixture was stirred at room temperature for 2 hours
7. distillationThereafter, the solvent was distilled off under reduced pressure
8. customto obtain a residue to which 200 ml of tetrahydrofuran
9. additionwas added
10. stirringthe mixture was stirred at 40° C. for 1 hour
11. temperatureAfter cooling to room temperature
12. customthe deposited solid was isolated by filtration
13. washwashed with 50 ml of tetrahydrofuran
14. customThe resultant solid was dried under reduced pressure at 50° C. for 5 hours

ORD record

ord-cb5bc640b0cc41df928d7997200763d6

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09068055B2