Phosphoric Acid → HCID 69731219, compound

Participants

Reaction Conditions

Reaction Steps

To a previously cooled (−15° C.) solution of 5 g of 4-methoxybenzyl 7β-phenylacetamido-3-methylenecepham-4-carboxylate in 200 ml of anhydrous dichloromethane, 8.9 ml of anhydrous pyridine and, subsequently, 7.3 g of PCl5 are added under stirring, and stirring is continued for 1 hour at −15° C. The reaction mixture is cooled to −30° C., 55.4 ml of absolute methanol are added thereinto, the mixture is stirred 90 minutes at −15° C. then 60 minutes at 0° C. and finally 60 minuts at 25° C. To the resulting mixture, 200 ml of a 0.5 M solution of K2HPO4 are added, the the pH is adjusted to bout 2 by addition of 5% H3PO4. The mixture is let to stand 30 minutes under stirring at 25° C., then the organic phase is separated, the organic one is extracted twice with dichloromethane and the collected organic phases are dried over sodium sulfate and concentrated under reduced pressure. The obtained oily residue is dissolved in 70 ml of ethyl acetate, the solution is cooled to 0° C. and treated first with a solution of 3.15 g of p-toluene sulfonic acid monohydrate in 70 ml of ethyl acetate, then with 70 ml of diethyl ether. After standing overnight at 4° C., the precipitate is filtered to give 3.92 g of practically pure (thin layer chromatography, eluent ethyl acetate/n-hexane 7/3, Rf=0.20) 4-methoxybenzyl 7β-amino-3-methylenecepham-4-carboxylate p-toluenesulfonic acid addition salt.

Provenance & Evidence