Potassium Bicarbonate → 3-Acetylthiomethyl-7-[{2-(2-amino-4-thiazolyl)-2-methoxyiminoacetyl}amino]-ceph-3-eme-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

1 g of potassium bicarbonate was added at 20° C. to a suspension of 5.48 g of the product of Step C in 10.6 ml of water and 912 mg of thiourea and after dissolution, the solution was stirred at 20° C. under nitrogen for 6 hours. The gummy precipitate started forming after 11/2 hours and then 30 ml of water and 3 ml of formic acid were added thereto. After cooling to 5° C., the mixture was vacuum filtered and the filter was washed with water containing 10% of formic acid. The residue was dissolved towards 5° C. in 30 ml of water containing triethylamine and then 3 ml of formic acid were added at 5° C. The mixture was vacuum filtered and the solid was empasted with water containing formic acid. The brown gum formed was removed and the combined aqueous phases were passed through carbon black to form a clear yellow solution. The solution was saturated with ammonium sulfate and was vacuum filtered. The precipitate was empasted with water and was vacuum filtered and washed with water to obtain precipitate A. The mother liquors were saturated with ammonium sulfate and the mixture was vacuum filtered. The solid was washed 3 times with water to obtain precipitate B. Precipitates A and B were combined and taken up in ethanol. The mixture was stirred for an hour at 20° C. and then stood at 0° C. for 16 hours. The mixture was vacuum filtered and the solid was washed with ethanol, with ether and dried under reduced pressure to obtained the syn isomer of 3-acetylthiomethyl-7-[{2-(2-amino-4-thiazolyl)-2-methoxyiminoacetyl{amino]-ceph-3-eme-4-carboxylic acid identical to the products of Examples 6 and 18.

Provenance & Evidence