Water → p-Nitrobenzyl alpha-[3-phenoxymethyl-7-oxo-4-thia-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl]-alpha-(1-toluene-p-sulfonyloxyethylidene)acetate

Participants

Reaction Conditions

Reaction Steps

To a solution of p-nitrobenzyl α-[3-phenoxymethyl-7-oxo4-thia-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl]-α-(1-hydroxyethylidene)acetate (940 mg) in dimethylformamide containing 10% tetrahydrofuran (5 ml) is added toluene-p-sulfonyl chloride (456 mg). After cooling to -70° C., the solution is mixed with triethylamine (0.3 ml). The reaction mixture is allowed to warm slowly up to room temperature, poured into water, and extracted with ethyl acetate. The extract solution is washed with water, dried, and evaporated. The obtained residue is chromatographed over silica gel containing 10% water using benzene containing 5% ethyl acetate to give p-nitrobenzyl α-[3-phenoxymethyl-7-oxo-4-thia-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl]-α-(1-toluene-p-sulfonyloxyethylidene)acetate (644 mg). IR: νmaxCHCl3 1785, 1735 cm-1. NMR: δCDCl3 2.45s3H, 4.75+4.20ABq (14 Hz)2H, 5.15s2H, 5.77s2H, 8.30-6.60m 13H.

Provenance & Evidence