Hydrochloric Acid → 2-[3-(Tert-butoxycarbonyl-methyl-amino)-prop-1-ynyl]-thiazole-4-carboxylic acid

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Reaction Steps

To a solution of 2-[3-(tert-butoxycarbonyl-methyl-amino)-prop-1-ynyl]-thiazole-4-carboxylic acid ethyl ester (1.22 g, 3.76 mmol) in THF (10 mL) was added aqueous solution of sodium hydroxide (2 M, 2.82 mL, 5.64 mmol) at RT. After stirring 3 h at RT, the reaction mixture was acidified with 2M aqueous solution of HCl until pH 2, and the solution was extracted with ethylacetate (20 mL). The aqueous layer was re-extracted with ethylacetate (20 mL) and the combined organic layers were washed with brine (10 mL), dried over sodium sulfate, filtered, and evaporated under reduced pressure to 2-[3-(tert-butoxycarbonyl-methyl-amino)-prop-1-ynyl]thiazole-4-carboxylic acid (1.11 g, quant.), which can be used in the next step without further purification. 1H-NMR (400 MHz, d6-DMSO): δ=13.2 (br, 1H), 8.55 (s, 1H), 4.37 (s, 2H), 2.89 (s, 3H), 1.45 (s, 9H). MS: m/z=297 (M+1).

Provenance & Evidence