Hydrochloric Acid → 1-(4-Benzyloxy-benzenesulfonyl)-5-methoxy-piperidine-2-carboxylic acid

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Reaction Steps

A mixture of 1-(4-benzyloxy-benzenesulfonyl)-5-hydroxy-piperidine-2-carboxylic acid (0.10 g, 0.26 mmol) and 1:1 THF-N-methylpyrrolidin-2-one (1 mL) was treated with NaH (0.031 g, 0.78 mmol, 60% dispersion in mineral oil). After stirring for 10 min, the mixture was warmed to room temperature, stirred for 20 min and treated with iodomethane (0.016 mL, 0.26 mmol). After stirring fro 3 h, the mixture was treated with an additional 0.010 g of NaH and 0.015 mL of iodomethane. The resulting mixture was stirred for 24 h, acidified with 1M HCl, extracted 3× with ethyl acetate, and the combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. Purification of the residue by radial chromatography (1:1 to 2:1 ethyl acetate hexane containing 1% of acetic acid, 2 mm silica gel plate) afforded 0.077 g (75%) of 1-(4-benzyloxy-benzenesulfonyl)-5-methoxy-piperidine-2-carboxylic acid as a colorless syrup:

Provenance & Evidence