Benzyl chloroformate → 1-Benzyl 4-tert-butyl 2-phenylpiperazine-1,4-dicarboxylate

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Reaction Steps

A solution of tert-butyl 3-phenylpiperazine-1-carboxylate (0.95 g, 3.6 mmol), benzyl chloroformate (0.85 g, 5.0 mmol) and diisopropylethylamine (1.0 g, 7.7 mmol) in dioxane (20 mL) was heated to 95° C. for 3 hours. After cooling, the reaction mixture was diluted with ethyl acetate (100 mL), and washed with saturated aqueous sodium bicarbonate (50 mL) and brine (25 mL). After drying over anhydrous sodium sulfate, filtration and concentration, the residue was purified by silica gel column chromatography (ethyl acetate/hexanes, 1:8) to give 1-benzyl 4-tert-butyl 2-phenylpiperazine-1,4-dicarboxylate (0.84 g, 59% yield).

Provenance & Evidence