Further studies on CAB approach toward chemical conversion of C19-diterpenoid alkaloids to taxoids: synthesis of the vital intermediate C-nor-aconanone.
In the title study, the synthesis of the vital intermediate C-nor-aconanone (3) from 4 was completed through 11 steps, mainly including semipinacol rearrangement, formation of the imines by the treatment of 10 or 20 with NBS, the cleavage of N-C19 bonds in 11 or 21 by treatment with m-CPBA and subsequently with LTA, as well as the rupture of the N-C17 bonds in 22 by a modified Nef reaction (NaH/t-BuOH --> KMnO4/H2O). One-pot procedure was successfully developed starting from 11 or 21 to afford the N,19-seco-C-nor product 15 or 22, respectively, in reasonably good yields.
Shen
Xiang-Li
XL
Department of Chemistry of Medicinal Natural Products, West China College of Pharmacy, Sichuan University, Chengdu, China.
Chen
Qiao-Hong
QH
Wang
Feng-Peng
FP
D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry*; D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry*; D004365:Drugs, Chinese Herbal / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D043823:Taxoids / Q000138:chemical synthesis* / Q000737:chemistry*
D000470:Alkaloids; D004224:Diterpenes; D004365:Drugs, Chinese Herbal; D043823:Taxoids