Potassium Carbonate → 6-Benzyloxycarbonylamino-8-hydroxy-5,6,7,8-tetrahydroquinoline

Participants

Reaction Steps

To a stirred solution of 8-acetoxy-6-benzyloxycarbonylamino-5,6,7,8-tetrahydroquinoline, cis-trans mixture (1.73 g, 5.07 mmol) in methanol (16 mL) at room temperature under nitrogen was added 10% aqueous potassium carbonate solution (8 mL, 5.79 mmol). After 24 h, the reaction mixture was diluted with methylene chloride. The organic layer was washed sequentially with saturated aqueous ammonium chloride solution and brine, dried over anhydrous magnesium sulfate, and evaporated under vacuum to obtain the title compound (1.47 g, 97%). Silica gel chromatography (eluted with 5% methanol in chloroform) provided inefficient separation of the cis and trans isomers. The cis isomer eluted first. Stereochemical assignment was made based on NOE experiments. Cis isomer: 13C NMR (400 MHz, CDCl3) δ 156.3, 155.8, 147.5, 138.0, 136.5, 128.5, 128.1, 123.1, 77.4, 67.5, 66.5, 44.4, 35.0. HPLC/MS [M+H]+, 299.

Provenance & Evidence