Triethylamine → (4-methoxyphenyl)methyl (6R)-7-[[(2Z)-2-[(1S)-2-benzhydryloxy-1-(3,4-dihydroxyphenyl)-2-oxoethoxy]imino-2-[2-(tritylamino)-1,3-thiazol-4-yl]acetyl]amino]-3-(chloromethyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Participants

Reaction Steps

60.5 g (0.0794 mol) of (Z)-2-[[(S)-α-benzhydryloxycarbonyl-3,4-dihydroxybenzyl]oxyimino]-2-(2-tritylaminothiazol-4-yl)acetic acid and 32.2 g (0.0794 mol) of p-methoxybenzyl 7-amino-3-chloromethyl-3-cephem-4-carboxylate were suspended in 600 ml of tetrahydrofuran, and 22.1 ml (0.158 mol) of triethylamine was added thereto at -5° C. The mixture was stirred at the same temperature for 30 minutes. Then, 18.5 ml (0.198 mol) of phosphorus oxychloride was dropwise added thereto at a temperature of from -10° to -5° C. over a period of 15 minutes. After stirring for 10 minutes, 27.6 ml (0.198 mol) of triethylamine was added thereto at a temperature of at most -5° C., and the mixture was stirred at a temperature of at most 5° C. for 1.5 hours. The reaction mixture was added to a mixed solution of 500 ml of water and 300 ml of ethyl acetate and subjected to liquid separation. The aqueous layer was further extracted with 100 ml of ethyl acetate, and the extract was put together with the organic layer. 120 ml of a saturated sodium hydrogencarbonate aqueous solution was gradually added to the organic layer, and the mixture was stirred for one hour. Then, the organic layer was washed with 400 ml of a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to obtain a foam-like solid. The foam-like solid thereby obtained was subjected to silica gel column chromatography (Wakogel® C-300, hexane/ethyl acetate =10/3→10/9). The desired fractions were put together and concentrated under reduced pressure to obtain 44.0 g (yield: 50%) of p-methoxybenzyl 7-[(Z)-2-[[(S)-α-benzhydryloxycarbonyl-3,4-dihydroxybenzyl]oxyimino]-2-(tritylaminothiazol-4-yl)acetamido]-3-chloromethyl-3-cephem-4-carboxylate as a foam-like solid.

Provenance & Evidence