تفاعل #543536

معادلة التفاعل

5-chloro-2-hydroxybenzamide

pyridine

hydrochloric acid

Ethyl chloroformate

→

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

المردود 85.3%

المذيبات

water

acetonitrile

ظروف التفاعل

المعالجة

1. 1
   workup.DISTILLATIONthe volatiles were distilled off (43 ml)
2. 2
   درجة الحرارةThe reaction was cooled to room temperature
3. 3
   أخرىto form
4. 4
   ترشيحThe resulting solid was filtered
5. 5
   أخرىrecrystallized in hot ethanol

الإجراء التجريبي

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.

المصدر