Experiments on the degradation of cephalosporin C

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Abstract
Cephalosporin C is relatively stable in dilute acid at room temperature, but is rapidly inactivated at pH 12. Inactivation in alkaline solution at 20[degree] is accompanied by the loss of an absorption band at 260 mu and the liberation of 2 acidic groups. Hydrol- ysis with alkali at 100[degree] results in the formation of substances which behave like alpha-aminoadipic acid and glycine, respectively, on paper chromatograms. Cephalosporin C is inactivated by an enzyme in partly purified preparations of penicillinase from Bacillus cereus, with loss of its absorption band at 260 m[mu] and liberation of one acid group. Hydrolysis of cephalosporin C with dilute acid at 105[degree] results in the liberation of CO2, volatile base, D-alpha-aminoadipic acid and traces of glycine. Little or no penicillamine appears to be formed. Hydrolysis of the dinitro-pyenyl derivative of cephalosporin C results in the liberation of dinitrophenyl-alpha-aminoadipic acid. Cephalosporin C absorbs 1 mole of H in the presence of a palladium-charcoal catalyst, yielding a product which has little antibacterial activity but which still shows an absorption maximum at 260 m[mu] Hydrolysis of the product with dilute acid at 105[degree] results in the formation of alpha-aminoadipic acid and glycine. Treatment of the hydrolysate with bromine water yields a small amount of a substance which be -haves like penicillaminic acid on paper chromatograms. Hydrolysis with dilute acid at 105[degree] of the material obtained by hydro-genolysis of cephalosporin C with Raney nickel yields D-alpha-aminoadipic acid, valine which is extensively racemized but which appears to contain an excess of the D-form, and smaller amounts of L-alanine and glycine. In yielding aline, alanine, and glycine after hydrogenolysis cephalosporin C resembles the penicillins. The dinitrophenyl and benzoyl derivatives of cephalosporin C are more active against Staphylococcus aureus and less active against Salmonella typhi than the parent compound.
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