反应详情

Trifluoroacetic acid (125 mg, 1.1 mmol) was added at 0° C. to a solution of 2-oxa-7-azaspiro[3.5]nonane-7-carboxylic acid tert-butyl ester (U.S. Pat. No. 7,105,507 B2; 50 mg, 0.22 mmol) in dichloromethane, then after 1 h the reaction mixture was concentrated to afford the title compound (83 mg), which contained approximately one additional equivalent of trifluoroacetic acid. Colorless oil, 1H-NMR (300 MHz, DMSO-d6): 8.4 (br. s, 2H), 4.32 (s, 4H), 3.05-2.95 (m, 4H), 1.95-1.9 (m, 4H).

1. concentration50 mg, 0.22 mmol) in dichloromethane, then after 1 h the reaction mixture was concentrated