Proton resonance spectra of heterocycles. Part V. 4(1H)-cinnolone and substituted 4-cinnolones
Abstract
The literature n.m.r. assignment for 4-cinnolones is revised. The spectra of substituted 4-cinnolones are used to confirm the gross structures of 4-cinnolones and to investigate the tautomerism of some sulphonic acid derivatives. The effect of substituents on chemical shifts and coupling constants in the cinnolone series is discussed.