反应详情

One dissolves p-nitrobenzyl α-[4-methoxymethylthio-3-phenoxyacetamido-2-oxo-azetidin-1-yl]-α-(1-hydroxyethylidene)acetate (1.06 g) in tetrahydrofuran (10 ml), cools to -40° C. under nitrogen atmosphere, adds triethylamine (489 mg) dissolved in tetrahydrofuran (1 ml) and methanesulfonyl chloride (252 mg) dissolved in tetrahydrofuran (1 ml), and stirs for 30 minutes at -40° C. and for 45 minutes at 0° C. To this solution, one adds morpholine (209 mg) dissolved in tetrahydrofuran (1 ml), keeps at 0° C. for 2 hours, adds N-bromosuccinimide (392 mg), keeps at 0° C. for 1.5 hour, adds water, and removes the separated oily material, and extracts with ethyl acetate. The extract solution and the removed oily material is combined, dried over magnesium sulfate, and evaporated. Purification of the obtained residual oil (1.4 g) by chromatography over silica gel containing 5% water (20 g) gives p-nitrobenzyl α-[4-methoxymethylthio-3-phenoxyacetamido-2-oxo-azetidin-1-yl]-α-(1-morpholino-2-bromoethylidene)acetate (700 mg; Yield: 52%) and p-nitrobenzyl α-[4-methoxymethylthio-3-phenoxyacetamido-2-oxo-azetidin-1-yl]-α-(1-morpholinoethylidene)acetate (170 mg; Yield: 14%).

1. customcools to -40° C. under nitrogen atmosphere
2. waitfor 45 minutes at 0° C
3. waitkeeps at 0° C. for 2 hours
4. waitkeeps at 0° C. for 1.5 hour
5. customremoves the separated oily material, and extracts with ethyl acetate
6. dry with materialdried over magnesium sulfate
7. customevaporated
8. customPurification of the obtained residual oil (1.4 g) by chromatography over silica gel containing 5% water (20 g)