Phenylacetyl chloride → (S)-N-(Methylsulfonyl)-2-oxo-3-[(phenylacetyl)-amino]-1-azetidinecarboxamide

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Reaction Conditions

Reaction Steps

(S)-N-Methylsulfonyl)-2-oxo-3-amino-1-azetidinecarboxamide, hydrochloride salt (189 mg; see example 6) was suspended in 8 ml of dry acetonitrile and 0.54 ml of triethylamine, and stirred at room temperature under nitrogen until solution occurred (about 15 minutes). The solution was cooled to 0°to 5° C., and then phenyl acetylchloride (153 μl) was added. The reaction was stirred at room temperature for 3 hours and then poured into 10 ml of 0.5 M pH 5.5 monobasic potassium phosphate buffer. The pH was adjusted to 7 (dilute potassium hydroxide) and the solution was extracted twice with ethyl acetate. The aqueous layer was covered with fresh ethyl acetate, and the pH was adjusted to 2 (3N hydrochloric acid). Repeated extraction with ethyl acetate gave an acidic ethyl acetate extract, which was dried (sodium sulfate) and evaporated to a residue (196 mg). Chromatography of this material on 20 g of SilicAR CC-4 using ethyl acetate/dichloromethane (1:1) provides 96 mg of crystalline product after removal of solvent. Recrystallization from ethyl acetate/dichloromethane provides an analytical sample having a melting point 168°-170° C., dec.

Provenance & Evidence