Phenylsulphonylacetylmethylenetriphenylphosphorane → methylene-(2S,5R)-3,3-dimethyl-7-oxo-6-[3-(phenylsulphonyl)-2-oxopropylidene]-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate

Participants

Reaction Steps

A solution of 3.3 g of methylene-6,7-dioxo-3,3-dimethyl-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate in 100 ml of benzene is treated at room temperature with 6 g of phenylsulphonylacetylmethylenetriphenylphosphorane. After 10 minutes, the reaction mixture is evaporated. The residue is chromatographed on silica gel while eluting with cyclohexane/ethyl acetate (6:4). There is obtained methylene-(2S,5R)-3,3-dimethyl-7-oxo-6-[3-(phenylsulphonyl)-2-oxopropylidene]-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate pivalate as yellow crystals of melting point 100°-102° [Rf: 0.25; cyclohexane/ethyl acetate (6:4)].

Provenance & Evidence