REVISED C-13 NMR ASSIGNMENTS FOR NORDITERPENOID ALKALOIDS WITH 7,8-METHYLENEDIOXY AND 10-BETA-OH GROUPS

C-13-nmr chemical shift assignments for the norditerpenoid alkaloids deltaline [1], deltamine [2], dictyocarpine [3], and 14-acetyldictyocarpine [5] have been revised on the basis of a study of their 1D, 2D, and selective INEPT nmr spectra. These revisions suggest that the C-13-nmr chemical shift assignments for twenty-eight other norditerpenoid alkaloids possessing 7,8-methylenedioxy and 10beta-OH groups may have to be revised. Complete H-1-nmr chemical shift assignments for compounds 1-3 and 5 are also reported.