2-Naphthalenesulfonyl chloride → 4-Hydroxy-1-(naphthalene-2-sulfonyl)-1,2,5,6-tetrahydro-pyridine-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A suspension of 31.15 g (150 mmol) 3-Ethoxycarbonyl-4-piperidone hydrochloride was suspended in 400 ml hexamethyldisilazane and heated under reflux (140° C.) for 2.5 h. The solution was evaporated complete, the residue dissolved in 400 ml THF and treated with 34 g (150 mmol) of naphthalene-2-sulfonylchloride in 150 ml THF. The reaction was stirred 16 h at room temperature, evaporated, treated with 400 ml aqueous 10% NaCl, stirred for 10 min and extracted with EtOAc (3×400 ml). The organic phase was dried (Na2SO4) and evaporated and crystallized from Et2O at 5° C. to give 53.1 g (90%) of 4-hydroxy-1-(naphthalene-2-sulfonyl)-1,2,5,6-tetrahydro-pyridine-3-carboxylic acid ethyl ester, MS: 362 (MH+).

Provenance & Evidence