Abstract: A method for the removal of the formyl group from an ester of an N-formyl peptide or N-formyl aminoacid, in which the ester is reacted with urea in the presence of a polar solvent and a strong acid.

Abstract: There is described a new class of ketohydroxyimino derivatives of cephalosporins of the formula ##STR1## wherein: R is an alkyl radical having from 2 to 4 carbon atoms, a phenyl, or a 5-membered heterocyclic radical which may be substituted, containing nitrogen, oxygen and/or sulphur;R.sup.1 is an acetoxy, carbamoyloxy or S-heterocyclic group, which may be substituted, and the heterocyclic ring is a 5- or 6-membered ring containing one or more nitrogen atoms, alone or combined with sulphur;R.sup.2 is hydrogen, alkyl or acetyl.The present compounds have an interesting broad-spectrum antibacterial activity.

Abstract: Formyl derivatives of hydrazinopenicillins of the formula ##STR1## wherein R is thienyl or phenyl, R' is hydrogen, formyl or alkyl containing from 1 to 3 carbon atoms and R" is hydrogen or formyl, provided that at least one of R' and R" is a formyl group, the carbon atom with the asterisk indicating a center of asymmetry of the molecule, and pharmaceutically acceptable salts and esters thereof, as mixture or as separated epimers. These compounds have antibacterial activity against Gram-negative and Gram-positive bacteria and are prepared by a process wherein the corresponding hydrazinopenicillin is reacted under anhydrous conditions with acetoformic anhydride to give the desired compounds.