Sodium hydride → 2-[4,5-Bis-(p-methoxyphenyl)-thiazol-2-ylthio]-2-formylacetic acid ethyl ester

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Reaction Steps

3.3 g of 4,5-bis-(p-methoxyphenyl)-thiazoline-2-thione are dissolved in 50 ml of hexamethylphosphoric acid triamide, the solution is cooled to 5° and converted into the sodium salt under nitrogen with sodium hydride (0.5 g of a 50% strength suspension in mineral oil, de-oiled with hexane). The product is allowed to warm to room temperature, 2.0 g of 2-bromoformylacetic acid ethyl ester are added dropwise and the mixture is stirred at 25° for 1 hour, poured into 750 ml of ice-water and taken up in diethyl ether. The ethereal phase is washed with water, dried over magnesium sulphate and concentrated to dryness by evaporation. 2-[4,5-bis-(p-methoxyphenyl)-thiazol-2-ylthio]-2-formylacetic acid ethyl ester is obtained, which can be used without further purification.

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