Triethylamine → 2-(4-Bromophenyl)-1,2-dihydro-3H-1,2,4-triazol-3-one

Participants

Reaction Steps

To a stirred suspension of compound 84a (1.14 g, 4.69 mmol) in toluene (25 mL) was added Et3N (0.913 mL, 6.57 mmol) and (PhO)2PON3 (1.012 g, 4.69 mmol) and the mixture was heated slowly over 20 min to reflux. Gas evolution began at 75° C. and became more vigorous at 100° C. After 1 h at reflux, an additional portion of (PhO)2PON3 (0.304 mL, 1.41 mmol) was added and the reaction was refluxed for an additional 30 min. The mixture was cooled to rt and extracted with 1M NaOH (3×75 mL). The combined aqueous extracts were washed with Et2O (2×25 mL) and adjusted to pH 1 with 3M HCl. The resultant precipitate was collected by filtration, washed with water (3×20 mL), and dried under suction and then high vacuum to afford a beige solid which was recrystallized from EtOAc-heptanes to afford compound 84b as a granular light yellow solid. Mass spectrum (LCMS, ESI pos.): Calcd. for C8H6BrN3O, 240.0/242.0 (M+H). found 240.1/242.1

Provenance & Evidence