Methanol → 1,3-Benzoxazole-5-carboxylic acid

HRID 22650Notes

Reaction equation

HRID 22650 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:5](C(O)=O)=[CH:4][C:3]=1O.[CH:12]([O:17]C)(OC)[O:13]C.[CH3:19][OH:20]>>[O:20]1[C:3]2[CH:4]=[CH:5][C:9]([C:12]([OH:17])=[O:13])=[CH:10][C:2]=2[N:1]=[CH:19]1

Participants

4

Reactant 3

HCID 887MethanolHCID 9005Trimethyl orthoformateHCID 1375664-Amino-3-hydroxybenzoic acid

Product 1

HCID 190067671,3-Benzoxazole-5-carboxylic acidYield 27%

Conditions

Temperature
100 °C

Procedure

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.

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-276c8222e05b4b89872ddd3a5f775d4e
Source dataset
uspto-grants-2005_02
Patent number
US06849620B2

Reaction notes

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