Hydrochloric Acid → 5-(4,5,7-Trifluorobenzothiazol-2-ylthio)pentanoic acid ethyl ester

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Reaction Steps

Sodium hydride (60% in oil, 220 mg, 5.5 mmol) was suspended in DMF (2 ml) and the suspension was stirred on a water bath. To the suspension was added dropwise a solution of 4,5,7-trifluoro-2-mercaptobenzothiazole (1.1 g, 5 mmol) in DMF (5 ml) under ice cooling and the mixture was stirred for 30 min. at room temperature and then cooled on a water bath. To the cooled mixture was added dropwise a solution of ethyl 5-bromopentanoate (1.05 g, 5 mmol) in DMF (3 ml) and the mixture was stirred for 2 hours at room temperature. The resultant mixture was diluted with water, then acidified with 7% hydrochloric acid and extracted with ethyl acetate. The organic layer was washed with an aqueous saturated saline solution, dried and then evaporated. The resulting residue was purified on a silica gel column to give 5-(4,5,7-trifluorobenzothiazol-2-ylthio)pentanoic acid ethyl ester (1.1 g, 64%) as an oil.

Provenance & Evidence