Phosphorus trichloride → 3-Acetonyl-2-benzhydryloxycarbonyl-7-[2-methoxyimino-2-(2-tritylaminothiazol-4-yl)-acetamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene

Participants

Reaction Conditions

Reaction Steps

A solution of 3-acetonyl-2-benzhydryloxycarbonyl-7-[2-methoxyimino-2-(2-tritylaminothiazol-4-yl)-acetamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide (5 g) in a mixture of methylene chloride (60 cc) and N,N-dimethylacetamide (2.3 cc) is cooled to -10° C. Phosphorus trichloride (1.01 cc) is then added and the mixture is stirred for one hour at -10° C. The reaction mixture is diluted with ethyl acetate (300 cc), washed successively with a saturated solution of sodium bicarbonate (50 cc) and distilled water (300 cc), dried over sodium sulphate and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 20° C. This yields the syn isomer of 3-acetonyl-2-benzhydryloxycarbonyl-7-[2-methoxyimino-2-(2-tritylaminothiazol-4-yl)-acetamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (4.5 g) in the form of a hard yellow foam.

Provenance & Evidence