m-Chloroperbenzoic acid → HCID 20276295, compound

Participants

Reaction Steps

A solution of 85% pure meta-chloroperbenzoic acid (4.31 g) in methylene chloride (50 cc) is added dropwise, over a period of 30 minutes, to a solution, cooled to between 0° and -5° C., of 2-benzhydryloxycarbonyl-3-(1-bromo-2-oxoethyl)-7-t-butoxycarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (mixture of the diastereoisomers at the substituent in the 3-position) (14.69 g) in methylene chloride (150 cc). After 30 minutes at -5° C., the reaction mixture is poured into a mixture of a semi-saturated solution of sodium bicarbonate (100 cc) and methylene chloride (200 cc). The organic phase is washed with distilled water (150 cc) and a semi-saturated solution of sodium chloride (150 cc) and then dried over sodium sulphate and concentrated to dryness under reduced pressure (30 mm Hg; 4 kPa) at 20° C. to give crude 2-benzhydryloxycarbonyl-3-(1-bromo-2-oxoethyl)-7-t-butoxycarbonylamino-8 -oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide (mixture of the diastereoisomers at the substituent in the 3-position) (13.35 g) in the form of a hard, light brown foam. The crude product obtained is divided into 2 batches, which are chromatographed on a column (height: 30 cm, diameter: 5 cm) of silica gel (0.04-0.063 mm), elution being carried out under a pressure of 0.4 bar (40 kPa) with a mixture of cyclohexane and ethyl acetate (40/60 by volume), and 125 cc fractions being collected. Fractions 7 to 10 from both chromatographic separations are combined and concentrated to dryness under reduced pressure (30 mm HG; 4 kPa) at 20° C. to give 2-benzhydryloxycarbonyl-3-(1-bromo-2-oxoethyl)-7-t-butoxycarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide (mixture of the diastereoisomers at the substituent in the 3-position) (2.43 g) in the form of a hard yellow foam.

Provenance & Evidence