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nbm110金虫 (小有名气)
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[求助]
（有机化学）求翻译~~金币嫌少可追加~~高手闲暇时光帮下忙哦~~~
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Free N–H indoles can also be obtained from 2-alkynyltrifluoroacetanilides in the presence of CuI and 1,2-trans-cyclohexanediamine or PPh3 (Scheme 4). As observedwith the related palladium-catalyzed synthesis of indoles,thetrifluoroacetamido substituent plays a crucial role in promoting this transformation. Under the same conditions, moderate yields were obtained with 2-alkynylanilines or with the corresponding acetamido derivatives. Furthermore, the trifluoroacetamido group provides the additional advantage of being readily cleaved (the amide bond is broken during the reaction or/and the work-up) so as to allow for the formation of the free N–H pyrrole nuclei, avoiding troublesome and time-consuming deprotecting steps.The copper-catalyzed intramolecular hydroamination protocol has been exploited to develop microwave-assisted solid-phase syn- theses of indoles. Under microwave irradiation,N-acyl-2-alkyl- 5-arenesulfamoylindoles have been obtained from resin-bound 2-alkynylanilides, after cleavage from the resin with trifluoroacetic acid in dichloromethane (Scheme 5).More recently, a linker containing a tripeptide unit with dual functions for anchoring the 2-alkynylanilide fragment onto a solid support and for promoting a copper-mediated heterocyclization has been developed (Scheme 6). N-Acyl chains contained in the indole derivative after cleavage can be easily removed upon exposure to pyrrolidine, which results in an indirect traceless20 solid-phase synthesis. The effect of the tripeptide unit on the cyclization step has been explained by a metal-catching (via formation of a Cu(II) complex through the amide carbonyl oxygen donors) and activation mechanism (via chelation of the copper ion with the neighboring alkyne fragment) (Fig. 1). |
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小刘渊
金虫 (正式写手)
- 翻译EPI: 9
- 应助: 36 (小学生)
- 金币: 1223.1
- 散金: 145
- 红花: 1
- 帖子: 489
- 在线: 122.8小时
- 虫号: 1525769
- 注册: 2011-12-06
- 专业: 聚合物共混与复合材料
【答案】应助回帖
nbm110(金币+70, 翻译EPI+1): ★★★★★最佳答案 好 欢迎继续~我还会发的哦~ 2012-02-08 21:34:33
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哈哈，哥们，我又来拿你的金币了，还是同一篇文章。 此外，无N-H哚吲还可以通过以下方法制备（路线4），用2-乙炔基三氟乙酰苯胺为原料，在CuI和1,2-反式-二氨基环己烷或三苯基磷存在的情况下制备。在观察到的钯催化合成哚吲的反应中，三氟乙酰苯胺取代物在促进该转变的过程中起到了至关重要的作用。而在相同的条件下，如果用2-乙炔基苯胺或是用相应的乙酰苯胺衍生物来制备则产量中等（并不高）。此外，三氟乙酰苯胺基团还有其它的优势，它的的化合价很容易断裂（酰胺键在反应或者实验的过程中可以断裂）以便于形成无N-H的吡咯核，从而避免了繁杂和耗时的去保护步骤。铜催化的分子内氢胺化反应被用于微波辅助的固相合成哚吲。在微波的引发下，用载于树脂上的2-乙炔基苯胺，利用溶于二氯甲烷的三氟乙酸与树脂剥离成功合成了N-酰基-2-烷基-5-氨芳磺酰吲哚（路线5）。最近利用一种含有三肽单元和两个可以将2-乙炔基苯胺固定到固体基材上的连接物质，并可以利用铜调节的杂环化反应被成功开发出来（路线6）。哚吲中的N-乙炔基链段可以在剥离后通过与吡咯烷酮的反应而很容易地被移除，从而可以产生间接的20固相合成。三肽在环化过程中的作用可以被解释为金属捕捉作用（羰基中氧可以与CUII形成结合物）和促进作用（可以与邻近的炔基一起螯合铜离子）。 |
2楼2012-02-08 21:29:06