13C- and 1H-NMR. Assignments for colchicine derivatives

The 13C‐NMR. spectra of a number of colchicine derivatives are given comprising examples of the normal series (4→10), iso series (11→16) and colchicine series (17), which were either reported in the literature or obtained by partial synthesis or degradation reactions. The 13C‐NMR. assignments were made by comparisons with known compounds and selective single‐frequency offresonance decoupling experiments. Selective proton decoupling experiments have also allowed assignments of the H—C(11) and H—C(12) protons of the iso and colchicine series.