Triethylamine → 1-(2-Bromo-5-fluorophenyl)-1H-1,2,4-triazol-5(4H)-one

To a stirred suspension of 2-(2-(2-bromo-5-fluorophenyl)hydrazono)acetic acid (2.65 g, 10.2 mmol) in toluene (80 mL) was added triethylamine (1.42 mL, 10.2 mmol) and diphenylphosphoryl azide (2.2 mL, 10.2 mmol). The resulting mixture was slowly heated to reflux temperature and the reflux was maintained for 1 h. The clear orange solution was cooled and then poured onto 10% aqueous KOH (100 mL). The basic extract was acidified (pH 1) with concentrated HCl. The precipitate that formed was collected by filtration, washed with water and dried at reduced pressure to afford the title compound as a yellow solid (1.75 g, 67% yield): 1H NMR (400 MHz, DMSO-D6) δ ppm 11.87 (1H, s), 8.10-8.08 (1H, m), 7.83 (1H, dd, J=8.8, 5.8 Hz), 7.50 (1 H, dd, J=9.1, 3.0 Hz), 7.34 (1H, td, J=8.6, 3.0 Hz); LCMS (+ESI, M+H+) m/z 258-260.

1. temperatureThe resulting mixture was slowly heated
2. temperatureto reflux temperature
3. temperaturethe reflux was maintained for 1 h
4. temperatureThe clear orange solution was cooled
5. extractionThe basic extract
6. customThe precipitate that formed
7. filtrationwas collected by filtration
8. washwashed with water
9. customdried at reduced pressure

ORD record

ord-1840b3cc038d4aaa9dc47b6ca99e6837

Source dataset

uspto-grants-2011_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08039458B2