Ethyl orthoformate → 7-chloro-3-ethyl-5-methyl-3H-imidazo[4,5-b]pyridine-6-carboxylic acid, ethyl ester

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Reaction Steps

25.7 g. of 5-amino-6-ethylamino-4-chloro-2-methylpyridine-3-carboxylic acid, ethyl ester (0.1 mol.) is refluxed for 12 hours with 100 ml. of orthoformic acid triethyl ester with stirring. The excess ester is removed in vacuo and the oily residue distilled to obtain 7-chloro-3-ethyl-5-methyl-3H-imidazo[ 4,5-b]pyridine-6-carboxylic acid, ethyl ester, b.p. 195° 0.01. Yield 23 g. (86%).

Provenance & Evidence