反应详情

A mixture of ethyl 4-[[[(7-chloro-2,3-dihydro-1,4-benzodioxin-5-yl)carbonyl]-amino]methyl]-3-methoxy-1-piperidinecarboxylate (0.051 mol) and potassium hydroxide (0.5 mol) in ethanol (200 ml) was stirred and refluxed for 30 hours and then cooled. The solvent was evaporated. The residue was dissolved in water and the solvent was evaporated again. The residue was partitioned between DCM and water. The organic layer was separated, dried, filtered, and the solvent was evaporated. The residue was purified by column chromatography over silica gel (eluent : CH2Cl2/(CH3OH/NH3)93/7). The pure fractions were collected and the solvent was evaporated, yielding 9 g of (cis)-7-chloro-2,3-dihydro-N-[(3-methoxy-4-piperidinyl)methyl]-1,4-benzodioxin-5-carboxamide (interm. 3-i). Part of interm. (3-i) was dissolved in 2-propanol and converted into the ethanedioic acid salt (1:1). The precipitate was filtered off and dried, yielding 1.2 g of (cis)-7-chloro-2,3-dihydro-N-[(3-methoxy4-piperidinyl)methyl]-1,4-benzodioxin-5-carboxamide ethanedioate (1:1) (interm. 3-j, mp. 208° C.).

1. filtrationThe precipitate was filtered off
2. customdried