• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Enantiospecific stereospecific total synthesis of the oxindole alkaloid (+)-alstonisine and stereocontrolled total synthesis of (-)-11-methoxy-17-epivincamajine as well as studies directed toward the total synthesis of N(b)-demethylalstophylline oxindole.
【24h】

Enantiospecific stereospecific total synthesis of the oxindole alkaloid (+)-alstonisine and stereocontrolled total synthesis of (-)-11-methoxy-17-epivincamajine as well as studies directed toward the total synthesis of N(b)-demethylalstophylline oxindole.

机译：对映体立体定向总合成的羟吲哚生物碱（+）-阿司他汀和立体控制的总合成（-）-11-甲氧基-17-表艾维卡那嗪，以及针对N（b）-去甲基阿糖胞苷羟吲哚的总合成的研究。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The first enantiospecific stereospecific total synthesis of alstonisine has been accomplished in an overall yield of 12% (from D-tryptophan methyl ester) in 17 reaction vessels. D-(+)-Tryptophan has served here both as the chiral auxiliary and the starting material. The stereospecific conversion of D-(+)-tryptophan methyl ester 144 into the key template (-)- Na H, Nb-benzyl tetracyclic ketone 9 via the asymmetric Pictet-Spengler reaction (600 gram scale) and Dieckmann cyclization on multi-hundred gram scale was reduced to only two reaction vessels. In the course of this work, a method that would provide entry into either spirocyclic oxindole, diastereomeric at C(7), has been developed. The diastereospecific osmylation process permitted the conversion of the 2,3-indole double bond of 177 into the oxindole moiety of 195 in 81% yield. Mechanistic studies of the stereoselective osmylation of the 2,3-indole double of indole alkaloids has been carried out. Compelling evidence for the intramolecular delivery of OsO4 via Nb-complexation was obtained with the hydrochloride salt of ketone 193 in the osmylation process. A practical method for the removal of the Nb-benzyl protecting group in the hindered azabicyclo[3.2.1]nonane system has been developed. The structure of alstonisine was determined by NOE spectroscopic experiments and was confirmed by single crystal X-ray analysis. This confirmed the configuration of the spirocenter at C(7) in alstonisine was the same as in the structure proposed earlier by Le Quesne on biogenetic grounds. The original structure of alstonisine reported by Nordman (X-ray crystallography) in 1963 was the enantiomer of natural alstonisine.;A stereocontrolled total synthesis of (-)-11-methoxy-17-epivincamajine 247, which comprises the southern unit of the bisindole alkaloid (-)-11-methoxy-10-(11 '-vincorinyl)-17-epivincamajine 246, was accomplished in an overall yield of 8.4% in 14 reaction vessels from N a-methyl-6-methoxy-D-(-)-tryptophan ethyl ester. The 6-methoxy tryptophan ethyl ester 213 has been synthesized on 300 gram scale via a palladium catalyzed heteroannulation process. The regiospecific synthesis of the template, 11-methoxy tetracyclic ketone 217, was executed enantiospecifically via the asymmetric Pictet-Spengler reaction in 46% overall yield (from iodoaniline 209). The synthesis of 16-epi- Na methylgardneral 222 and 16-epi- Na-methylgardnerine 223 has been accomplished in high yield and in stereospecific fashion via the enolate-driven, palladium-catalyzed cross coupling reaction. (Abstract shortened by UMI.).
机译：在17个反应容器中，以18％的总收率（来自D-色氨酸甲酯）完成了对阿司他汀的首次对映体立体定向全合成。 D-（+）-色氨酸在这里既用作手性助剂又用作起始原料。 D-（+）-色氨酸甲酯144通过不对称Pictet-Spengler反应（600克规模）和Dieckmann环化在数百个上立体定向转化为关键模板（-）-Na H，Nb-苄基四环酮9克规模减少到只有两个反应器。在这项工作的过程中，已经开发出了一种方法，该方法可以进入C（7）的非对映体螺环羟吲哚。非对映异构化的osmylation过程允许将81的2,3-吲哚双键转换为195的羟吲哚部分。已经进行了吲哚生物碱的2，3-吲哚双体的立体选择性osmylation的机理研究。令人信服的证据表明，在渗透过程中，酮193的盐酸盐可通过Nb络合物分子内递送OsO4。开发了一种实用的方法来去除受阻氮杂双环[3.2.1]壬烷体系中的Nb-苄基保护基。阿尔斯通碱的结构通过NOE光谱实验确定，并通过单晶X射线分析证实。这证实了在阿尔斯通的C（7）螺中心的构型与Le Quesne先前在生物遗传学上提出的结构相同。诺曼（X射线晶体学）在1963年报道了阿尔斯通的原始结构是天然阿尔斯通的对映异构体。（-）-11-甲氧基-17-表文卡他汀247的立体控制全合成，其中包括双吲哚的南部单元在14个反应容器中，由N-甲基-6-甲氧基-D-（-）在14个反应容器中以8.4％的总收率获得了生物碱（-）-11-甲氧基-10-（11'-vincorinyl）-17-表艾维卡那嗪246。 ）-色氨酸乙酯。已经通过钯催化的杂环化方法以300克规模合成了6-甲氧基色氨酸乙酯213。通过不对称的Pictet-Spengler反应以对映体特异性地进行模板的11-甲氧基四环酮217的区域特异性合成，总产率为46％（来自碘苯胺209）。通过烯醇盐驱动的钯催化的交叉偶联反应，以高收率和立体定向的方式完成了16-表位-甲基萘二酚222和16-表位-甲基萘啶223的合成。 （摘要由UMI缩短。）。

著录项

  • 作者

    Wearing, Xiangyu Z.;

  • 作者单位

    The University of Wisconsin - Milwaukee.;

  • 授予单位 The University of Wisconsin - Milwaukee.;
  • 学科 Chemistry Organic.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 302 p.
  • 总页数 302
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号