Reacción #50928

Ecuación de reacción

4-amino-3-hydroxybenzoic acid

trimethyl orthoformate

MeOH

→

1,3-benzoxazole-5-carboxylic acid

Rendimiento 27.0%

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe mixture is cooled to rt
2. 2
   FiltraciónThe resulting solution is filtered through a pad of Celite
3. 3
   Concentraciónthe filtrate is concentrated in vacuo

Procedimiento

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.

Fuente