反应详情

To a solution of 7β-[2-(5-amino-1,2,4-thiadiazol-3-yl) -2-ethoxyiminoacetamido]-3-(1-methyl-1-piperazinio)methyl-3-cephem-4-carboxylate (syn isomer) (255 mg) in a mixture of water (5 ml) and acetone (5 ml) was added 4,5-diacetoxy-2-pyridinecarbonyl chloride hydrochloride (309 mg), with maintaining the pH of the solution to 8.0-8.5 by addition of saturated aqueous sodium bicarbonate. After stirring for 30 minutes, acetone was removed by evaporation in vacuo and the residue was adjusted to pH 8 and stirred for 2 hours. The mixture was adjusted to pH 3.0 with 1N hydrochloric acid and chromatographed on Diaion HP-20 (50 ml), and the elution was carried out with 10% aqueous isopropyl alcohol. The eluate was lyophilized to give 7β-[2-(5-amino-1,2,4-thiadiazol-3-yl) -2-ethoxyiminoacetamido]-3-[1-methyl-4(4,5-dihydroxy-2-pyridylcarbonyl)-1-piperazinio]methyl-3-cephem-4-carboxylate (syn isomer) (155 mg).

1. temperaturewith maintaining the pH of the solution to 8.0-8.5
2. customacetone was removed by evaporation in vacuo
3. stirringstirred for 2 hours
4. customchromatographed on Diaion HP-20 (50 ml)
5. washthe elution