Diethyl Ether → 7beta-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-allyloxyiminoacetamido]-3-[3-acetamido-2-(2-hydroxyethyl)-1-pyrazolio]methyl-3-cephem-4-carboxylate

Participants

Reaction Steps

To a solution of di(trifluoroacetic acid) salt of 7β-amino-3-[3-acetamido-2-(2-acetoxyethyl)-1-pyrazolio]methyl-3-cephem-4-carboxylate (1 g) and N-(trimethylsilyl)acetamide (2.01 g) in dichloromethane (20 ml) was added (Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-allyloxyiminoacetyl chloride hydrochloride (0.520 g) under stirring and ice-cooling. The mixture was stirred for one hour at room temperature. The reaction mixture was added to ether under stirring and ice-cooling. The produced amorphous solid was dried in vacuo and dissolved in water. The aqueous solution was adjusted to pH 13 with 1N aqueous sodium hydroxide under stirring at -3°~0° C. and stirred for 2 hours at the same temperature. The aqueous solution was adjusted to pH 2 with 1N hydrochloric acid and subjected to column chromatography on Diaion HP-20 and the elution was carried out with 10% aqueous isopropyl alcohol. The fractions containing the object compound were combined, concentrated to remove isopropyl alcohol and lyophilized to give 7β-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2-allyloxyiminoacetamido]-3-[3-acetamido-2-(2-hydroxyethyl)-1-pyrazolio]methyl-3-cephem-4-carboxylate (syn isomer) (222 mg).

Provenance & Evidence