Trimethyl orthoformate → 1,3-Benzoxazole-6-carboxylic acid

HRID 22651

Reaction equation

HRID 22651 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[OH:11].[CH:12](OC)(OC)OC>CO>[O:11]1[C:3]2[CH:4]=[C:5]([C:6]([OH:8])=[O:7])[CH:9]=[CH:10][C:2]=2[N:1]=[CH:12]1

Participants

4

Reactant 2

HCID 9005Trimethyl orthoformateHCID 1375664-Amino-3-hydroxybenzoic acid

Product 1

HCID 222459381,3-Benzoxazole-6-carboxylic acidYield 89.1%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
100 °C

Procedure

A mixture of 4-amino-3-hydroxybenzoic acid (250 mg, 1.63 mmol) and trimethyl orthoformate (500 μL, 4.57 mmol) are heated in an oil bath at 100° C. for 2 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-6-carboxylic acid as a brown solid (237 mg, 89%): 1H NMR (DMSO-d6) δ 13.2, 8.9, 8.3, 8.0, 7.9.

Workup

  1. temperatureThe mixture is cooled to rt
  2. filtrationThe resulting solution is filtered through a pad of Celite
  3. concentrationthe filtrate is concentrated in vacuo

Sources & evidence

ORD record
ord-fbd8bd71cb8f49ea9adabc6685f8a2b2
Source dataset
uspto-grants-2005_02
Patent number
US06849620B2

Linked notes

Loading…