N-bromobutanimide → Benzyl(4aR,7aR)-2-(benzoylamino)-7a-(5-bromothiophen-2-yl)-4a,5,7,7a-tetrahydropyrrolo[3,4-d][1,3]thiazine-6(4H)-carboxylate

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Reaction Steps

To a stirred clear and colorless solution of benzyl(4aR,7aR)-2-benzamido-7a-(2-thienyl)-4,4a,5,7-tetrahydropyrrolo[3,4-d][1,3]thiazine-6-carboxylate (1.67 g, 3.50 mmol) in dimethylformamide (35 mL) at room temperature, under an atmosphere of nitrogen is added N-bromosuccinimide (747 mg, 4.20 mmol). The resulting pale yellow solution is stirred at room temperature for 50 minutes. The solution is diluted with ethyl acetate (150 mL) and washed with water (3×50 mL) and brine (50 mL). The organic phase is separated, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue is purified by silica gel flash chromatography eluting with a hexanes/ethyl acetate, gradient from 80:20 to 0:100, to give the title compound (1.79 g, 92%) as a white solid: ES/MS (m/z): 557.8 (M+H).

Provenance & Evidence