反応 #50928

反応方程式

4-amino-3-hydroxybenzoic acid

trimethyl orthoformate

MeOH

→

1,3-benzoxazole-5-carboxylic acid

収率 27.0%

反応条件

後処理

1. 1
   温度The mixture is cooled to rt
2. 2
   ろ過The resulting solution is filtered through a pad of Celite
3. 3
   濃縮the filtrate is concentrated in vacuo

実験手順

A mixture of 4-amino-3-hydroxybenzoic acid (1.0 g, 6.5 mmol) and trimethyl orthoformate (2.0 mL, 18.3 mmol) is heated in an oil bath at 100° C. for 30 h. The mixture is cooled to rt and diluted with MeOH. The resulting solution is filtered through a pad of Celite, and the filtrate is concentrated in vacuo to give 1,3-benzoxazole-5-carboxylic acid as a brown solid (290 mg, 27%): 1H NMR (DMSO-d6) δ 13.0, 8.9, 8.3, 8.1, 7.9.

出典