Trimethyl orthoacetate → 2-Methyl-1,3-benzoxazole-6-carboxylic acid

HRID 22652

Reaction equation

HRID 22652 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].[C:12](OC)(OC)(OC)[CH3:13]>CO>[CH3:12][C:13]1[O:11][C:3]2[CH:4]=[C:5]([C:6]([OH:8])=[O:7])[CH:9]=[CH:10][C:2]=2[N:1]=1

Participants

4

Reactant 2

HCID 15050Trimethyl orthoacetateHCID 1375664-Amino-3-hydroxybenzoic acid

Product 1

HCID 184756892-Methyl-1,3-benzoxazole-6-carboxylic acidYield 46%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
100 °C

Procedure

A mixture of 4-amino-3-hydroxybenzoic acid (500 mg, 3.7 mmol) and trimethyl orthoacetate (1.0 mL, 7.9 mmol) is heated in an oil bath to 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 2-methyl-1,3-benzoxazole-6-carboxylic acid as an off-white solid (266 mg, 46%): 1H NMR (DMSO-d6) δ 13.1, 8.2, 8.0, 7.7, 2.7.

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-af000238386540ac9820b39fca3a2c3b
Source dataset
uspto-grants-2005_02
Patent number
US06849620B2

Linked notes

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