Buxus alkaloiks. Part XI. The synthesis of cycloprotobuxine-A (3β,20S-chirality) and its two isomeric alkaloids with 3β,20R- and 3α,20R- configuration from lanosterol.
作者:Tatsuhiko Nakano、Alfonso Martín、MigueL Alonso
DOI:10.1016/s0040-4020(01)96027-2
日期:1991.5
The synthesis of cycloprotobuxine-A (5),representative of Buxus alkaloids, and its two isomeric alkaloids with 3β,20R- and 3α,20R-configuration, from lanosterol, is described. In order to confirm the stereochemistries at C-3 and C-20 in these three alkaloids, the 3β-dimethylamino-(27) and the 3α-dimethylamino derivative (28) of cycloartanol (24) were also synthesised and their 1H and 13C n.m.r. spectra