Gluco-indole alkaloids from Nauclea cadamba in Thailand and transformation of 3α-dihydrocadambine into the indolopyridine alkaloid, 16-carbomethoxynaufoline

Abstract

Three monoterpenoid gluco-indole alkaloids, 3β-isodihydrocadambine, cadambine, and 3α-dihydrocadambine, were isolated from Nauclea cadamba ROXB. growing in Thailand. The stereochemistry at C19 in 3β- isodihydrocadambine was elucidated to be R by spectroscopic analysis. Treatment of 3α-dihydrocadambine with β-glucosidase in aqueous ammonium acetate solution gave an indolopyridine alkaloid, 16-carbomethoxynaufoline, and an unusually rearranged compound. © 2003 Pharmaceutical Society of Japan.