Sodium ethoxide → 7-Hydroxy-5-oxo-4,5-dihydro-2-thia-4-aza-indene-6-carboxylic acid ethyl ester

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Reaction Steps

Sodium ethoxide (4.75 g, 66.34 mmol) was added to a solution of 4-(2-ethoxycarbonyl-acetylamino)-thiophene-3-carboxylic acid methyl ester (19) (8.57 g, 31.59 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 by cold diluted HCl solution. The solids formed were filtered, washed by water and dried under vacuum at room temperature to get 4.3 g (57%) of 7-hydroxy-5-oxo-4,5-dihydro-2-thia-4-aza-indene-6-carboxylic acid ethyl ester as white solid. MP 193° C.; 1H NMR (400 MHz, DMSO-d6) δ 1.27 (t, J=7.2 Hz, 3H), 4.28 (q, J=7.2 Hz, 2H), 6.83 (d, J=3.2 Hz, 1H), 8.24 (d, J=3.6 Hz, 1H), 11.10 (s, 1H), 12.90 (s, 1H) ppm; MS m/z=240 amu (M++1).

Provenance & Evidence