8-(4-Tert-butoxycarbonyl-piperazin-1-yl)-6-chloro-2,3-dihydro-benzo[1,4]oxazine-4-carboxylic acid benzyl ester → 4-(6-chloro-3,4-dihydro-2H-benzo[1,4]oxazin-8-yl)-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

A solution of 8-(4-tert-butoxycarbonyl-piperazin-1-yl)-6-chloro-2,3-dihydro-benzo[1,4]oxazine-4-carboxylic acid benzyl ester (870 mg, 1.79 mmol) in ethanol (10 mL) was hydrogenated at atmospheric pressure over 10% Pd/C (75 mg) for 0.5 hour. The catalyst was removed by filtration, and the filtrate was concentrated. The crude material was purified by flash chromatography on silica gel (eluting with hexane-ethyl acetate; 1:1, v/v) to give 4-(6-chloro-3,4-dihydro-2H-benzo[1,4]oxazin-8-yl)-piperazine-1-carboxylic acid tert-butyl ester as a white foam (450 mg, 71%). MS: MH+=354.

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