Revised 13C Nmr Assignments for Norditerpenoid Alkaloids with 7,8-Methylenedioxy and 10β-OH Groups

13C-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 13C-nmr chemical shift assignments for twenty-eight other norditerpenoid alkaloids possessing 7,8-methylenedioxy and 10 beta-OH groups may have to be revised. Complete 1H-nmr chemical shift assignments for compounds 1-3 and 5 are also reported