一鍋式反應製備含氮雜環之研究

One pot preparations of nitrogen containing heterocyclic compounds

廖經互(Chin-Hu Liao)

指導教授 ： 楊嘉喜

中原大學/理學院/化學研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500465

摘要

本文主要是研究一鍋式多步驟反應，合成2,3,7-三氮-二環[3.3.0]辛烯化合物，反應是先由丙烯基鹵化物與疊氮化鈉形成丙烯基疊氮，經一次分子間[3+2]偶極環化反應，然後進行開環反應，再經過一次分子內[3+2]偶極環化反應及一次麥可加成反應。在以前的方法中，丙烯基鹵化物與疊氮必須先反應並分離出丙烯基疊氮，在此研究則是直接以丙烯基鹵化物與疊氮化鈉及具拉電子基(如酮基、氰基、酯基)的烯類在一鍋於適當溫度、溶劑下有效率地合成出雙環雜環化合物，使步驟減少一步。
此一鍋式反應中，丙烯基疊氮與具拉電子基為酮基、酯基可成功合成2,3,7-三氮-二環[3.3.0]辛烯化合物；丙烯腈例子，因反應溫度提升而得到異構物；丙烯酸醯胺及二端拉電子烯類皆無法得到雙環雜環化合物；烷基鹵化物為起始物之反應在此ㄧ鍋式反應之研究中，則是反應性較為複雜。
此外，利用核磁共振光譜的1H-nmr定時追蹤溴化丙烯基與疊氮化鈉及拉電子基烯類在一鍋式多步驟反應之轉換情形，及反應路徑之探討。發現反應步驟中，丙烯基鹵化物與疊氮化鈉形成丙烯基疊氮是最慢的；另外，拉電子基為酮基之烯類，反應路徑不同於其他具拉電子基(氰基、酯基)的烯類。

關鍵字

含氮雜環 ； 一鍋式多步驟反應

並列摘要

This thesis addresses on one-pot reaction involving allyl bromide,sodium azide and alkene carrying electron-withdrawing group to prepare 7-substituted 2,3,7-triaza-bicyclo[3.3.0]octenes. Therein, allyl azide was fromed firstly from nucleophilic substitution of azide ion to allyl bromide and followed by an intermolecular [3+2] dipolar cycloaddition of allyl azide and alkene to give 2-pyrazoline which subsequently isomerized to a diazo compound with a double bound. This intermediate then underwent an intramolecular [3+2] dipolar cycloaddition to produce unsubstituted 2,3,7-triaza-bicyclo[3.3.0] octenes. A Michael addition of this compound to the alkene then give 7-substituted 2,3,7-triaza-bicyclo[3.3.0]octenes as the final compound. In previous protocol, allyl azide was prepared and separated first before it reacted with alkene , whereas in this improved protocol one step was saved by directly mixing allyl bromide, sodium azide and alkene in a suitable solvent under appropriate temperature to obtain the product in one-pot in good yield.
In this prottcol, if the alkene is alkyl acrylate or alkyl vinyl keton, the reaction give 7-substituted 2,3,7-triaza-bicyclo[3.3.0]oct-2-enes. However if the alkene is acrylonitrile, a further isomerization is occurred and the final product is 7-substituted 2,3,7-triaza-bicyclo[3.3.0]oct-3-enes. In the case of acrylamide as the alkene, no reaction was observed and if the alkene carrying two electron-
withdrawing groups at 1,2-position, the starting materials are all recovered. If allyl bromide is replaced by alkyl halide, the reaction is very complicated.
1H-NMR was used to monitor the reaction. It is found that in the case of methyl vinyl ketone as the alkene, azide ion is added favorably to methyl vinyl ketion, instead of allyl bromide, to from (2-azidoethyl) methyl ketone first.

並列關鍵字

nitrogen containing heterocyclic ； on one-pot reaction

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