CARBON-HYDROGEN AND CARBON-CARBON COUPLING PATTERNS IN THE CEPHALOSPORIN SERIES

The C-13 NMR spectra of the skeleton of 7-amino-3-cephem-4-carboxylic acid dagger derivatives and the 2-(2-aminothiazol-4-yl)-2-alkoxyiminoa cetyl substituent were analysed searching for the rules which might be helpful in the structure determination of new cephalosporin antibioti cs and their isomers. The C-13 NMR decoupled spectra were fully interp reted on the basis of C-11-H-1 and C-13-C-13 coupling patterns. The me thod for unambiguous assignment of the Z/E geometry of 2-(2-aminothiaz ol-4-yl)-2-alkoxyiminoacetyl groups was established.