Water → Diethyl 1-(3-benzyl-7-oxo-4-thia-2,6-diazabicyclo [3,2,0]hept-2-en-6-yl)-1-(p-nitrobenzyloxycarbonyl)-prop-1-en-2-yl phosphate

Participants

Reaction Conditions

Reaction Steps

To a solution 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 (4.53 g) containing 4-dimethylaminopyridine (0.1 g) in ethyl acetate (50 ml) under a nitrogen atmosphere at 20° C. was added triethylamine (1.53 ml) followed by diethylphosphoryl chloride (1.59 ml) dropwise. The reaction mixture was stirred at 20° C. for 3 hours. Water (40 ml) was added and the organic layer was separated, washed with water (20 ml) and saturated sodium chloride solution (20 ml), dried with magnesium sulphate and carbon treated, filtered and evaporated to give the title compound as a yellow viscous oil in essentially quantitative yield. TLC (silica) Rf 0.17 (dichloromethane/ethyl acetate 15:2). The product was a mixture of geometric isomers (ca. 2:1) about the enol phosphate double bond. NMR δCDCl3 1.11-1.60 (m, 6H), 1.98+2.60 (d, 3H), 3.73-4.65 (m, 6H), 5.22-5.42 (m, 2H), 5.88-6.28 (m, 2H) and 7.25-7.80 and 8.18-8.58 (m, 9H).

Provenance & Evidence