Hydrochloric Acid → (6S)-4-Nitrobenzyl 3-hydroxy-8-oxo-7-(N-phenylacetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Participants

Reaction Steps

One adds triethylamine (5.68 ml) to a stirred suspension of p-nitrobenzyl α-[3-benzyl-7-oxo-4-thia-2,6-diazabicyclo[ 3,2,0]hept-2-en-6-yl]-α-(1-hydroxyethylidene)acetate (9.06 g) in tetrahydrofuran (120 ml) under nitrogen atmosphere at -20° C. to give clear solution, adds methanesulfonyl chloride (1.65 ml) to the solution, stirs for 30 minutes at the same temperature, adds morpholine (1.92 ml), warms to 0° C., stirs for 5 hours, cools to -30° C. to -35° C., adds pyridine (1.54 ml) and bromine (3.12 g), stirs for 20 minutes, warms to ice-water temperature, adds 5% hydrochloric acid (144 ml) and methanol (120 ml), stirs for 3 hours at room temperature, and lets stand overnight at 0° C. Collection of the separated crystals in the reaction mixture by filtration gives p-nitrobenzyl 7-phenylacetamido-3-hydroxy-3-cephem-4-carboxylate (6.678 g). m.p. 201° C. Yield: 71%.

Provenance & Evidence