New reactivities of deltaline analogs: an efficient O-demethylation at C-1 and an unusual extrusion of the C-14 atom

被引：8

作者：

Tang, Pei ^{[1
]}

Chen, Qi-Feng ^{[1
]}

Wang, Ling ^{[1
]}

Chen, Qiao-Hong ^{[1
]}

Jian, Xi-Xian ^{[1
]}

Wang, Feng-Peng ^{[1
]}

机构：

[1] Sichuan Univ, Dept Chem Med Nat Prod, W China Coll Pharm, Chengdu 610041, Peoples R China

来源：

TETRAHEDRON | 2012年 / 68卷 / 27-28期

基金：

中国国家自然科学基金;

关键词：

C-19-Diterpenoid alkaloids; Deltaline; O-Demethylation; Extrusion; C-19-DITERPENOID ALKALOID DELTALINE; NORDITERPENOID ALKALOIDS; DEOXYGENATION REACTIONS; OXIDATION; ACID; RING;

D O I：

10.1016/j.tet.2012.04.055

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

O-Demethylation at C-1 in the C-19-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 basic condition probably via a sequence, including Grob fragmentation, aerobic oxidation, deformylation, and S(N)2 nucleophilic substitution, to give enone 21 (70%) and oxetane 22 (14%). The structure of compound 22 was confirmed by X-ray crystallographic analysis of its derivative 21. (c) 2012 Elsevier Ltd. All rights reserved.

引用

页码：5668 / 5676

页数：9