1-Ethyl-2-Methylbenzodiazole-5-carboxylic acid synthesis

Yield:-

Reaction Conditions:

in ethanol; for 7 h;Heating / reflux;

Steps:

11.C

C. 1-Ethyl-2-methyl-1 H-benzoimidazole-5-carboxylic acid; A mixture of 1.4 g (7.7 mmol) of the title B compound, 3-amino-4-ethylamino-benzoic acid and 15 mL (104 mmol) of triethyl orthoacetate in 20 mL of EtOH is refluxed for 7 h. The reaction mixture is allowed to cool to RT and the precipitated solid is collected by filtration, washed with EtOH (2x), then with methyl-t-butylether (MTBE) and dried in vacuo to give 1- ethyl-2-methyl-1 H-benzoimidazole-5-carboxylic acid as a grey solid : mp >250°C ; 'H-NMR (DMSO-d6) 8 12.65 (s, 1 H), 8.11 (s, 1 H), 7.82 (dd, 1 H), 7.59 (d, J = 8.46, 1 H), 4.26 (q, 2H), 2.57 (s, 3H), 1.30 (t, 3H); [M-1]-= 203.

References:

WO2003/82841,2003,A1 Location in patent:Page/Page column 51