2,4-Dinitrophenol → 7-[o-(N-Butoxycarbonyl-N-methylaminomethyl)phenylacetamido]-3-[2-(2-carboxyethyl)-2,3-dihydro-s-triazolo[4,3-b]pyridazin-3-on-6-ylthiomethyl]-3-cephem-4-carboxylic acid

Participants

Reaction Steps

To a mixture of 7-amino-3-[2-(2-carboxyethyl)-2,3-dihydro-s-triazolo[4,3-b]pyridazin-3-on-6-ylthiomethyl]-3-cephem-4-carboxylic acid (452 mg., 1 m.mole) and triethylamine (0.46 ml., 3.3 m.mole) in 50% aqueous acetonitrile (4 ml.) was added a THF solution (3ml.) of 2,4-dinitrophenyl o-(N-t-butoxycarbonyl-N-methylaminomethyl)phenylacetate prepared from o-(N-t-butoxycarbonyl-N-methylaminomethyl)phenylacetic acid (283 mg., 1.1 m.mole), 2,4-dinitrophenol (202 mg., 1.1 m.mole) and DCC (227 mg., 1.1 m.mole). The mixture was stirred at room temperature overnight and concentrated under reduced pressure to remove the organic solvents. The aqueous concentrate was washed with ether (3 × 20 ml.), acidified with c.HCl to pH 1 - 2 and extracted with ethyl acetate (5 × 20 ml.). The combined extracts were dried with anhydrous Na2SO4 and evaporated to dryness. The residue was chromatographed on a column of silica gel (Wako gel, C-200, 10 g.) by eluting with a mixture of MeOH-- CHCl3 (MeOH: 0 to 3%). The combined eluates which contained the desired product were evaporated to give 359 mg. (50%) of the title compound. M.P. > 150° C. (dec.).

Provenance & Evidence