Methanol → HCID 70511010, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 1.5 g (4 mMol) of pivaloyloxymethyl [3R,4S]-2-[4-chloro-3-(1-hydroxyisopropyl)-2-oxoazetidin-1-yl]-2-isopropylidenylacetate in 50 ml of dichloromethane is stirred at -78° C., to which is introduced ozone for 15 minutes. Consumption of the starting material is cofirmed by means of thin-layer chromatography. Introduction of nitrogen gas into the reaction mixture for 30 minutes gives a solution containing pivaloyloxymethyl [3R,4S]-2-[4-chloro-3-(1-hydroxyisopropyl)-2-oxoazetidin-1-yl]-2-oxoacetate. This solution is stirred at -10° C., to which are added 800 mg (8 mMol) of acetylacetone, then 20 ml of methanol dissolving 216 mg (4 mMol) of sodium methylate. The solvent is distilled off under reduced pressure, and the residue is stirred vigorously together with 20 ml of ethyl acetate, 1 ml of 1 N-hydrochloric acid and 10 ml of a saturated aqueous solution of sodium chloride. The organic layer is separated, dried over magnesium sulfate, and concentrated. The resulting reaction product is subjected to silica-gel column-chromatography (n-hexane-ethyl acetate 1:1-1:4). The fractions containing the desired product are combined and concentrated to give 80 mg of the titled compound as crystals, m.p. 109°-110° C.

Provenance & Evidence