Ethyl Acetate → Racemic 1,1-dimethylethyl 7-[2-(2-tritylaminothiazol-4-yl)-2-methoxyimino-acetamido]-3-(3-nitrophenylthio)-8-oxo-4-thia-1-azabicyclo[4,2,0]oct-2-ene-2-carboxylate

Participants

Reaction Steps

A suspension of 677 mg of diphosphorus tetraiodide in 7 ml of pyridine was stirred under an inert atmosphere for 5 minutes and then 780 mg of the product of Step A were added. The mixture was stirred for 2 hours and then a further 363 mg of diphosphorus tetraiodide were added. The stirring was maintained for 1 hour and the reaction mixture was poured into 50 ml of ethyl acetate and filtered. The filtrate was evaporated to dryness under reduced pressure and the residue was dissolved in methylene chloride. The organic phase was washed with 0.1N hydrochloric acid, then with water, dried and concentrated to dryness. The residue was chromatographed on silica and eluted with a mixture of chloroform and acetone (10-0.5) to obtain 348 mg of racemic 1,1-dimethylethyl 7-[2-(2-tritylaminothiazol-4-yl)-2-methoxyimino-acetamido]-3-(3-nitrophenylthio)-8-oxo-4-thia-1-azabicyclo[4,2,0]oct-2-ene-2-carboxylate which crystallized from ether.

Provenance & Evidence