Jerzy Winiarski

Carbon–hydrogen and carbon–carbon coupling patterns in the cephalosporin series

The 13C NMR spectra of the skeleton of 7-amino-3-cephem-4-carboxylic acid derivatives and the 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetyl substituent were analysed searching for the rules which might be helpful in the structure determination of new cephalosporin antibiotics and their isomers. The 13C NMR decoupled spectra were fully interpreted on the basis of 13C–1H and 13C–13C coupling patterns. The method for unambiguous assignment of the Z/E geometry of 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetyl groups was established.

Synthesis of (3,4) β-Methylenecepham and (3,4) β-Methylene-carbacepham via intramolecular carbene addition to double bond

Abstract A series of new (3,4) β-methylenecepham and carbacepham analogues were synthesised as potential antibacterial agents. The key step of the synthesis included presumed generation of the carbene species from the oxalimide substrate effected by triethylphosphite and its intramolecular addition to the double bond. The stereochemistry of the tricyclic system has been elucidated by NMR and X-ray crystallography. In preliminary screening, two of the synthesised compounds exhibited modest antibacterial activity at 1.5–2.0 mg/mL against a number of bacterial strains.