(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide is synthesised using (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylic acid as a raw material by chemical reaction. The specific synthesis steps are as follows:
DIPEA (5.8 mL, 36.2 mmol) was added to a solution of (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylic acid (5.0 g, 18.1 mmol), EDCI (5.2 g, 27.2 mmol), HOBT (3.7 g, 27.2 mmol) and NH4Cl (1.94 g, 36.2 mmol) in DMF (60 mL) at rt. The reaction mixture was stiffed for 17 hrs, then diluted with ice water (100 mL) and extracted with EtOAc (3*). The combined organic layer was dried over Na2SO4, and concentrated. The residue was purified by silica gel column chromatography (2:1 EtOAc/petroleum ether) to afford (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxamide (4.0 g, 80%) as a white solid. ESI-MS (EI+, m/z): 276 [M+H]+.