Benzenesulfonyl chloride → 4-[2-(1-Benzenesulfonyl-piperidin-3-yloxy)-phenyl]-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

The compound of Step 1 (2.5 g, 4.7 mmol) was dissolved in methanol (20 mL). Palladium on carbon (50% water, 2.1 g) was added. A hydrogen atmosphere was established using balloons, and the mixture was stirred at r.t. for about 4 hours. The catalyst was removed by filtration with ethyl acetate through a bed of celite. The compound was isolated by running scrub-plug with a gradient of 100% ethyl acetate (200 mL) to triethylamine in ethyl acetate (10%). The isolated product (0.36 g, 0.9 mmol) was dissolved in methylene chloride (10 mL) at 0° C., and triethylamine (0.38 mL, 2.7 mmol) was added. Benzenesulfonyl chloride (0.15 mL, 1.1 mmol) was added drop wise to the reaction mixture. The solution warmed to r.t., concentrated under reduced pressure and purified using silica gel chromatography (75% ethyl acetate in hexanes) to afford the final compound (0.400 g, 82%).

Provenance & Evidence