在C 19-二萜生物碱中,C-1处的O-脱甲基非常具有挑战性。在本文中,首先观察到δ(1)中的10-OH基是O-脱甲基化反应的决定因素。除去该羟基后,可以通过用HBr–HOAc处理,轻松除去相应的Deltaline类似物中的1- O-甲基。同时,可以在碱性条件下,通过Grob片段化,有氧氧化,甲酰基化和S N 2亲核取代等一系列顺序,将溴化物18或20中的C-14原子挤出,得到烯酮21(70%)和氧杂环丁烷22(14%)。化合物的结构通过其衍生物21的X射线晶体学分析证实了22。
Deoxygenation reactions of C19-diterpenoid alkaloids
作者:Palaniappan Kulanthaivel、S.William Pelletier
DOI:10.1016/s0040-4039(00)96410-4
日期:1987.1
Efficient methods for deoxygenation of secondary and tertiary alcohols of some C19-diterpenoid alkaloids are presented. Thus deltaline (1) was converted to delpheline (2) or to 10-deoxydeltaline (7); deltamine (8) to 6-deoxydetamine (10); and delpheline (2) to 6-deoxydelpheline (12). An unusual elimination product 4 was formed when chloro-derivative 3 was reduced with LiAlH4.
Deoxygenation reactions of c19-diterpenoid alkaloids
作者:Palaniappan Kulanthaivel、S.William Pelletier
DOI:10.1016/s0040-4020(01)86133-0
日期:1988.1
thiocarbonylimidazolyl derivatives: 14-acetyldelcosine (13) to 14-acetyl-l-deoxydelcosine (22); alkalinehydrolysis of 22 gave 1-deoxydelcosine (23); aconitine (24) to 3-deoxyaconitine (27); yunaconitine (25) to crassicauline A (28). Deoxygenation of 14-acetyldictyocarpine (30) via the chloro-derivative 31 gave 14-acetyl-10-deoxydictyocarpine (34). Reduction of 31 with LiAlH4 gave the unusualelimination product
New reactivities of deltaline analogs: an efficient O-demethylation at C-1 and an unusual extrusion of the C-14 atom
作者:Pei Tang、Qi-Feng Chen、Ling Wang、Qiao-Hong Chen、Xi-Xian Jian、Feng-Peng Wang
DOI:10.1016/j.tet.2012.04.055
日期:2012.7
O-Demethylation at C-1 in the C19-diterpenoid alkaloids is very challenging. In this paper, it was firstly observed that 10-OH group in deltaline (1) is a determining factor for the O-demethylation reaction. After removal of this hydroxyl group, 1-O-methyl group in the corresponding deltaline analogs can be readily removed by treatment with HBr–HOAc. Meanwhile, the C-14 atom in bromides 18 or 20 can be extruded under
在C 19-二萜生物碱中,C-1处的O-脱甲基非常具有挑战性。在本文中,首先观察到δ(1)中的10-OH基是O-脱甲基化反应的决定因素。除去该羟基后,可以通过用HBr–HOAc处理,轻松除去相应的Deltaline类似物中的1- O-甲基。同时,可以在碱性条件下,通过Grob片段化,有氧氧化,甲酰基化和S N 2亲核取代等一系列顺序,将溴化物18或20中的C-14原子挤出,得到烯酮21(70%)和氧杂环丁烷22(14%)。化合物的结构通过其衍生物21的X射线晶体学分析证实了22。