权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Exploration of Diels-Alder Reaction of 2-Vinylazoles as 1-Azadienes

2-乙烯基唑作为 1-氮杂二烯的 Diels-Alder 反应的探索

基本信息

批准号：
06672121
负责人：
SAKAMOTO Masanori
金额：
$ 1.02万
依托单位：
Meiji College of Pharmacy
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Nitrogen containing a six-membered ring system (piperidine ring) is a common partial structure of biologically active compounds. One of the most direct approaches to the system is the nitorogen containing hetero Diels-Alder reaction. 1 However, Diels-Alder reaction of 1-aza-1, 3-butadienes, simple alpha, beta-unsaturated imines, themselves have been difficult due to their low reactivities as dienes, side reactions and instabilities arising from the imine moieties. We found benzylidenecyanomethyl-1, 3-benzothiazoles and -1, 3-benzoxazoles (1) as 1-aza-1, 3-butadienes. The dienes (1) featuring the stabilized imine moieties by constituting heteroaromatic rings, react with both electron-deficient and electron-rich dienophiles. It was found that substrates having the diene systems and dienophiles moiety in the molecules smoothly caused stereoselective intramolecular Diels-Alder reaction to give polycyclic compounds via exo-transition state. Ethyl (E)-3-(1, 3-benzothiazol-2-yl)-3-cyanopropenoate (2) as 1-aza-1, 3-butadiene (2), bearing electronwithdrawing ester group at diene -4-position, reacts with electron -rich dienophiles under extremely mild conditions to give corresponding cycloadducts with regio-and endo-selectivities. Treatment of 2 with electron-donating allyl alcohols causes tandem transesterification and intramolecular cycloaddition to afford cis-fused polycyclic systems in a single step.

含氮六元环(哌啶环)是生物活性化合物中常见的部分结构。最直接的方法之一是含氮杂化的Diels-Alder反应。然而，1-氮杂-1，3-丁二烯，简单的α，β-不饱和亚胺本身的Diels-Alder反应是困难的，因为它们的反应活性低，副反应和亚胺部分引起的不稳定性。我们发现了亚甲基-1，3-苯并噻唑和-1，3-苯并恶唑(1)为1-氮杂-1，3-丁二烯。双烯(1)的特征是稳定的亚胺部分通过形成杂芳环，与缺电子和富电子的双烯亲和体反应。研究发现，分子中含有双烯体系和亲双烯基团的底物可以顺畅地引起分子内立体选择性Diels-Alder反应，通过外过渡态得到多环化合物。(E)-3-(1，3-苯并噻唑-2-基)-3-氰基丙烯酸乙酯(2)作为1-氮杂-1，3-丁二烯(2)，在二烯-4-位带有电子吸电子基团，在极温和的条件下与富含电子的双烯烃反应生成相应的具有区域和内向选择性的环加成产物。2与给电子体的烯丙醇反应，一步完成串联的酯交换反应和分子内的环加成反应，得到顺式稠合多环体系。