Two novel skeletal rearrangements involving in the C ring of C 19-diterpenoid alkaloid deltaline derivatives

Abstract

Treatment of compounds 2 and 5, both from the C19-diterpenoid alkaloid deltaline 1, with 5% NaOH methanol (room temperature, 16h) and NaOH-N,N-dimethylformamide (reflux, 10h) led to the two novel skeletal rearrangement products 4 (90%) and 6 (62%), respectively, involving Wagner-Meerwein rearrangement and Grob fragmentation. Their structures were fully characteristized based on 2D NMR and HR-MS data. © 2008 Pharmaceutical Society of Japan.