反应详情

NCS (290 mg, 2.17 mmol) and pyridine (2 drops) were added to a solution of (E)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carbaldehyde oxime (560 mg, 2.04 mmol) in dry DCM (15 mL). The reaction mixture was stirred at rt for about 3-4 hrs. Ethynyltrimethylsilane (240 mg, 2.44 mmol) was added, then a solution of DIPEA (290 mg, 2.24 mmol) in dry DCM (5 mL) was added slowly over a 0.5 h period. After addition, the reaction mixture was stirred at rt overnight. The reaction mixture was then washed with 10% citric acid, water, saturated sodium chloride (10 mL), dried and concentrated. The residue was purified by silica gel column chromatography (10:1 petroleum ether/EtOAc) to afford (2S,5R)-6-(benzyloxy)-2-(5-(trimethylsilyl)isoxazol-3-yl)-1,6-diazabicyclo[3.2.1]octan-7-one (300 mg, 41%) as a colorless oil. ESI-MS (EI+, m/z): 372 [M+H]+.

1. additionAfter addition
2. stirringthe reaction mixture was stirred at rt overnight
3. washThe reaction mixture was then washed with 10% citric acid, water, saturated sodium chloride (10 mL)
4. customdried
5. concentrationconcentrated
6. customThe residue was purified by silica gel column chromatography (10:1 petroleum ether/EtOAc)