反应详情

To a solution of PPh3 (2.2 g, 8.2 mmol) in dry DCM (60 mL) was added I2 (2.1 g, 8.2 mmol). After I2 was dissolved completely, TEA (1.7 g, 16.4 mmol) was added quickly at rt. The mixture was stirred for 15 mins. Tert-butyl 3-(2-(2-((2S,5R)-6-(benzyloxy)-7-oxo-1,6-diaza bicyclo[3.2.1]octane-2-carbonyl)hydrazinyl)-2-oxoethyl)azetidine-1-carboxylate (2.0 g, 4.1 mmol) was added. The mixture was stirred at rt for 1 h. The reaction mixture was concentrated and the residue was purified by silica gel column chromatography (gradient elution 0˜40% EtOAc/petroleum ether) to afford tert-butyl 3-((5-((2S,5R)-6-(benzyloxy)-7-oxo-1,6-diaza-bicyclo[3.2.1]octan-2-yl)-1,3,4-oxadiazol-2-yl)methyl)azetidine-1-carboxylate (1.3 g, 66%) as a white solid. ESI-MS (EI+, m/z): 470 [M+H]+.

1. stirringThe mixture was stirred at rt for 1 h
2. concentrationThe reaction mixture was concentrated
3. customthe residue was purified by silica gel column chromatography (gradient elution 0˜40% EtOAc/petroleum ether)