反应详情

One dissolves p-nitrobenzyl α-[3-benzyl-7-oxo-4-thia-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl]-α-(1-hydroxyethylidene)acetate (827 mg) in methylene chloride (10 ml), cools to -20° C., adds a solution of methanesulfonyl chloride (1 M in methylene chloride; 2.2 ml) and a solution of triethylamine (1 M in methylene chloride; 2.2 ml), stirs for 90 minutes, cools to -25° C., adds morpholine (0.35 ml), stirs for 65 minutes, adds N-bromosuccinimide (340 mg), and stirs for 1 hour. One washes the reaction mixture with water, dries over magnesium sulfate, and evaporates. Purification of the obtained residue by chromatography over silica gel containing 10% water (30 g) gives p-nitrobenzyl α-[3-benzyl-7-oxo-4-thia-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl]-α-(1-morpholino-2-bromoethylidene)acetate (710 mg). Yield: 65%.

1. customcools to -20° C.
2. customevaporates
3. customPurification of the obtained residue by chromatography over silica gel containing 10% water (30 g)