TY - JOUR
T1 - New syntheses of the Amaryllidacaea alkaloids vasconine, assoanine, oxoassoanine, pratosine and ismine by radical cyclisation
AU - Rosa, Ana M.
AU - Lobo, Ana M.
AU - Branco, Paula S.
AU - Prabhakar, Sundaresan
AU - Sá-da-Costa, Margarida
N1 - We thank Junta National de Investigação Cientffica e Tecnologica (JNICT, Lisbon) and PRAXIS program for partial financial support. Two of us, A. M. R and M. S. C., are grateful for the award of doctoral and graduatef ellowships respectively.
PY - 1997/1/6
Y1 - 1997/1/6
N2 - N-(2-bromo-4,5-dimethoxybenzyl)-N-(2'-β-hydroxyethylphenyl)amine when subjected to the action of AIBN and tri-n-butyltin hydride (TBTH) in benzene, under reflux, yielded the corresponding β-4-phenanthridinylethyl alcohol. While reduction of the tetracyclic quaternary salt obtained by treatment of this alcohol with PBr3 gave assoanine, its oxidation with alkaline ferricyanide led to a separable mixture of pratosine and oxoassoanine, its oxidation with alkaline ferricyanide led to a separable mixture of pratosine and oxoassoanine. The σ radical, similarly generated from 2-bromo-4,5-methylenedioxybenzyl-2'-aminophenylether, afforded the biphenyl alcohol, N-norismine.
AB - N-(2-bromo-4,5-dimethoxybenzyl)-N-(2'-β-hydroxyethylphenyl)amine when subjected to the action of AIBN and tri-n-butyltin hydride (TBTH) in benzene, under reflux, yielded the corresponding β-4-phenanthridinylethyl alcohol. While reduction of the tetracyclic quaternary salt obtained by treatment of this alcohol with PBr3 gave assoanine, its oxidation with alkaline ferricyanide led to a separable mixture of pratosine and oxoassoanine, its oxidation with alkaline ferricyanide led to a separable mixture of pratosine and oxoassoanine. The σ radical, similarly generated from 2-bromo-4,5-methylenedioxybenzyl-2'-aminophenylether, afforded the biphenyl alcohol, N-norismine.
UR - http://www.scopus.com/inward/record.url?scp=0031060463&partnerID=8YFLogxK
U2 - 10.1016/S0040-4020(96)00985-4
DO - 10.1016/S0040-4020(96)00985-4
M3 - Article
SN - 0040-4020
VL - 53
SP - 299
EP - 306
JO - Tetrahedron
JF - Tetrahedron
IS - 1
ER -