7-Aminocephalosporanic acid → 7-Amino-3-(4,6-diamino-pyrimidin-2-yl-thiomethyl)-ceph-3-em-4-carboxylic acid dihydrate

Participants

Reaction Conditions

Reaction Steps

2.7 g (0.01 mole) of 7-aminocephalosporanic acid are dissolved in 50 ml of water with the required amount of sodium bicarbonate. 1.7 g (0.013 mole) of 4,6-diamino-2-mercaptopyrimidine and the equivalent amount of sodium bicarbonate are added and the reaction solution is heated to 60° C. for 4 hours, whilst stirring and keeping the pH value constant (pH=7). The mixture is allowed to cool, undissolved material is filtered off and the filtrate is concentrated in vacuo at 30° C. to half its volume. The aqueous solution which remains is extracted several times with ethyl acetate and the aqueous phase is adjusted to a pH of 2 with 2 N hydrochloric acid. The precipitate is filtered off, washed with water until free from chloride and dried in vacuo at 37° C. over potassium hydroxide. 1.61 g of the title compound are obtained. Rf : 0.27 (acetone:glacial acetic acid =10:1) IR (KBr): 1,745 cm-1 (β-lactam band) NMR (d6 -DMSO, 60 MHz):

Provenance & Evidence