Reacción #543536

Ecuación de reacción

5-chloro-2-hydroxybenzamide

pyridine

hydrochloric acid

Ethyl chloroformate

→

6-chloro-2H-1,3-benzoxazine-2,4(3H)-dione

Rendimiento 85.3%

Disolventes

water

acetonitrile

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.DISTILLATIONthe volatiles were distilled off (43 ml)
2. 2
   TemperaturaThe reaction was cooled to room temperature
3. 3
   Otroto form
4. 4
   FiltraciónThe resulting solid was filtered
5. 5
   Otrorecrystallized in hot ethanol

Procedimiento

A solution of 10 g of 5-chloro-2-hydroxybenzamide (58.0 mmol), pyridine (22 ml) and acetonitrile (25 ml) was stirred in an ice bath. Ethyl chloroformate (6.1 ml, 0.0638 mol) was added dropwise. The pink solution was stirred for 30 minutes at <10° C. The ice bath was replaced with an oil bath. The reaction mixture was heated to 95° C. and the volatiles were distilled off (43 ml). The reaction was cooled to room temperature, causing a white solid to form. The mixture was poured into water (100 ml) and acidified with concentrated aqueous hydrochloric acid. The resulting solid was filtered and recrystallized in hot ethanol to give 9.77 g of 6-chloro-2H-1,3-benzoxazine-2,4(3H)-dione.

Fuente