Sodium ethoxide → 4,5-Dihydro-7-hydroxy-5-oxothieno[3,2-b]pyridine-6-carbonitrile

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Reaction Steps

Sodium ethoxide (3.10 g, 45.62 mmol) was added to a solution of 3-(2-cyano-acetylamino)-thiophene-2-carboxylic acid methyl ester (24) (3.10 g, 45.62 mmol) in anhydrous ethanol and refluxed overnight. The solution was cooled and excess solvent was distilled off. The residue was dissolved in water and acidified to pH 2 by cold diluted HCl solution. The solids formed were filtered, washed by cold water, and dried under vacuum at room temperature to yield 6.7 g (84%) of 7-hydroxy-5-oxo-4,5-dihydro-thieno[3,2-b]pyrdine-6-carbonitrile as white solids. MP>300° C.; 1H NMR (400 MHz, DMSO-d6) δ 6.96 (d, J=5.2 Hz, 1H), 8.04 (d, J=5.2 Hz, 1H), 12.10 (s, 1H) ppm; MS mz=193 amu(M++1).

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