Chloroacetyl chloride → 7-hydroxy-3,4-dihydro-2H-1,4-benzoxazin-3-one

Participants

Reaction Conditions

Reaction Steps

K2CO3 (250 g, 1.8 mol, 4 eq) was dissolved in water (1100 mL) in a 3 L round bottomed flask, vacuum degassed 3 times, then cooled to 0 to 5° C. 4-Amino resorcinol HCl (73 g, 0.45 mol, 1 eq) was added though a strong nitrogen purge, and the blue solution was again degassed 3×. Choroacetyl chloride (45 mL, 64 g, 0.57 mol, 1.25 eq) was dissolved in toluene (225 mL), and was added over 1 h maintaining the temperature below 5° C. the ice bath was removed, and the mixture (biphasic with suspended crystalline product) was stirred overnight. The intermediate 2 was then isolated via filtration giving 53 g (71%) after a water wash (550 mL) and drying.

Provenance & Evidence