Benzyl chloroformate → Benzyl [4-(benzyloxy)-3-fluorophenyl]carbamate

Participants

Reaction Steps

A solution of 34.9 g 1-benzyloxy-2-fluoro-4-nitro-benzene (WO03064413) (MW: 247.28, 141 mmol) and 340 mg platinium 5% on activated carbon in 350 ml ethyl acetate was stirred under hydrogen at rt and normal pressure. The reaction was monitored by HPLC and was complete after twenty hours. The catalyst was filtered over a glass fiber filter, and the filtrate evaporated under reduced pressure to dryness. The oily residue was dissolved in 500 ml acetone and treated with 250 ml of a saturated solution of sodium bicarbonate and 17.5 g of sodium bicarbonate (MW: 84.01, 208 mmol). The mixture was cooled to 5° C. and treated drop wise with 26.08 g of benzyl chloroformate (MW: 170.59, 152 mmol). The reaction was allowed to stirred at room temperature for two hours and monitored by TLC (hexane/ethyl acetate 3:1). The acetone was evaporated, the residue diluted with 500 ml water, and the solid filtered off. The crystals were washed with 500 ml water and dried. Yield: 48.05 g, 95.8%. MS: 352.5 (M+H)+, 350.8, (M−H)−. Method ESI+, ESI−.

Provenance & Evidence