Diethyl Malonate → 4-Tert-butyl-2-[5-(2,2-diethoxycarbonylethyl)benzofuran-2-yl]thiazole

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Reaction Steps

A solution of methylmagnesium bromide in tetrahydrofuran (1N, 15 ml) was added to diethyl malonate (7.33 g) at 0° C. for 10 minutes. The mixture was stirred for 2 hours at ambient temperature. To the mixture, 4-tert-butyl-2-(5-chloromethylbenzofuran-2-yl)thiazole (3.50 g) was added and stirred for 23 hours at 45° C. The resulting mixture was concentrated under reduced pressure and added to the solution of 4N hydrogen chloride in ethyl acetate. The resulting precipitates were collected by filtration and washed with n-hexane and diisopropyl ether to give the salt. The salt was added to the aqueous sodium hydrogen carbonate solution and extracted with ethyl acetate. The extract was washed with brine, dried over magnesium sulfate and concentrated under reduced pressure to give 4-tert-butyl-2-[5-(2,2-diethoxycarbonylethyl)benzofuran-2-yl]thiazole (5.80 g).

Provenance & Evidence