Trifluoroacetic acid → (6R,7R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-hydroxyiminoacetyl]amino]-8-oxo-3-(pyridin-4-ylmethylsulfanyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

Participants

Reaction Steps

To a suspension of diphenylmethyl 7β-[2-(2-aminothiazol-4-yl)-2-(Z)-(acetoxyimino)acetamido]-3-[(4-pyridyl)methylthio]-3-cephem-4-carboxylate (2.37 g, 3.51 m mol) in a mixture of dichloromethane (12 ml) and anisole (2.4 ml) was added trifluoroacetic acid (4.8 ml) at 5° C. and the mixture was stirred at the same temperature for 2 hours. The mixture was poured into IPE (300 ml) and the precipitates were collected by filtration, washed with IPE and dried in vacuo. The powder was suspended in a mixture of water (150 ml) and methanol (7.5 ml), and ammonium chloride (563 mg, 10.5 m mol) was added thereto. The mixture was stirred at room temperature with keeping the pH to 8 by addition of saturated NaHCO3 aqueous solution. The mixture was adjusted to pH ca. 6 by addition of 6N HCl and by evaporated in vacuo. The residue was adjusted to pH 3.5 by addition of 6N HCl and chromatographed on HP-20 (80 ml) and eluted with 5% aqueous IPA. The eluent was lyophilized and the crude product was purified by preparative HPLC to give 7β-[2-(2-aminothiazol-4-yl)-2-(Z)-(hydroxyimino)acetamido]-3-[(4-pyridyl)methylthio]-3-cephem-4-carboxylic acid (295 mg).

Provenance & Evidence