Ammonia → cis-4-amino-5-chloro-2,3-dihydro-N-[3-methoxy-1-(4-oxopentyl)4-piperidinyl]-2,2-dimethyl-7-benzofurancarboxamide hemihydrate

Participants

Reaction Steps

A mixture of 5.4 parts of cis-4-amino-5-chloro-2,3-dihydro-N-[3-methoxy-1-[3-(2-methyl-1,3-dioxolan-2-yl)propyl]-4-piperidinyl]2,2-dimethyl-7-benzofurancarboxamide and 85 ml of an aqueous sulfuric acid solution 1% was stirred for 2 hours at reflux temperature. After cooling, the reaction mixture was basified with ammonia and extracted with dichloromethane (2×). The combined extracts were dried, filtered and evaporated. The residue was purified by column chromatography (silica gel; CH2Cl2 /CH3OH 95:5). The eluent of the desired fraction was evaporated and the residue was suspended in 2,2'-oxybispropane. The product was filtered off and dried, yielding 2.4 parts (51.6%) of cis-4-amino-5-chloro-2,3-dihydro-N-[3-methoxy-1-(4-oxopentyl)-4-piperidinyl]-2,2-dimethyl-7-benzofurancarboxamide hemihydrate; mp. 137.7° C. (comp. 112).

Provenance & Evidence