反应 #543536

反应方程式

5-chloro-2-hydroxybenzamide

pyridine

hydrochloric acid

Ethyl chloroformate

→

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

收率 85.3%

溶剂

water

acetonitrile

反应条件

后处理

1. 1
   workup.DISTILLATIONthe volatiles were distilled off (43 ml)
2. 2
   温度The reaction was cooled to room temperature
3. 3
   其他to form
4. 4
   过滤The resulting solid was filtered
5. 5
   其他recrystallized in hot ethanol

实验过程

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.

来源