Ethyl chloroformate → HCID 178437954, compound

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Reaction Steps

Ethylchloroformate (0.30 ml, 3.08 mmol) was added to a stirred solution of the amidoxime of Example 8 (500 mg, 1.39 mmol) in pyridine (8 ml) at 0° C. under nitrogen and the resulting solution was stirred for 10 minutes. The mixture was concentrated under reduced pressure and the residue was dissolved in a mixture of water (4 ml), tetrahydrofuran (4 ml) and 1M aqueous sodium hydroxide solution (2 ml). The mixture was heated under reflux for 1 hour, cooled to room temperature and stirred for a further 2 days. The resulting solution was diluted with 2M aqueous hydrochloric acid (20 ml) and extracted with ethyl acetate (2×50 ml). The combined organic layers were washed with brine (50 ml), dried over magnesium sulphate, filtered and evaporated under reduced pressure to leave a yellow oil. The oil was purified by flash column chromatography on silica gel eluting with pentane:ethyl acetate (50:50, by volume) to yield a white solid. The solid was dissolved in a mixture of tetrahydrofuran (1 ml) and 1M aqueous sodium hydroxide solution (10 ml) and then heated under reflux for 24 hours. The resulting solution was diluted with 2M hydrochloric acid (20 ml) and extracted with dichloromethane (2×50 ml). The combined organic layers were washed with brine (50 ml), dried over magnesium sulphate, filtered and evaporated under reduced pressure to give the title compound (113 mg) as a white solid m.p. 94-96° C.

Provenance & Evidence