(2,5-difluorophenyl)urea synthesis

Yield:460346-05-8 740 mg (67%)

Reaction Conditions:

with ammonia in tetrahydrofuran;

Steps:

60 Preparation of 2,5-difluorophenyl urea (Intermediate 6)

Preparation of 2,5-difluorophenyl urea (Intermediate 6) To a solution of 2,5-difluorophenyl isocyanate (1 g, 6.45 mmol) in tetrahydrofuran (50 mL) at 0° C. was added a 28% aqueous solution of ammonia (30 mL). The mixture was stirred for 1 h allowing the temperature to warm up to room temperature, then concentrated under reduced pressure, taken into water and filtered. The solid was washed twice with water and with ether, then dried at 65° C. under reduced pressure to give 740 mg (67%) of intermediate 6. ¹H NMR [(CD₃)₂SO] δ8.53 (br s, 1H, NH), 8.02 (m, 1H), 7.21 (m, 1H), 6.72 (m, 1H), 6.29 (br s, 2H, NH₂).

References:

US2002/198198,2002,A1