与肼在环缩合反应中交叉共轭的烯酮的反应性：吡唑和吡唑啉的合成,The Journal of Organic Chemistry

当前位置： X-MOL 学术 › J. Org. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

与肼在环缩合反应中交叉共轭的烯酮的反应性：吡唑和吡唑啉的合成
The Journal of Organic Chemistry ( IF 3.3 ) Pub Date : 2021-05-06 , DOI: 10.1021/acs.joc.1c00569
Alexander A. Golovanov ₁ , Ivan S. Odin ₁ , Dmitry M. Gusev ₁ , Anna V. Vologzhanina ₂ , Ilya M. Sosnin ₁ , Stanislav A. Grabovskiy ₃

Affiliation

交叉共轭的烯酮，二烯酮和三烯酮（由于低成本的起始化合物而容易获得）与芳基肼的环缩合反应会导致吡唑衍生物（二杂芳基取代的乙炔，buta-1,3-diens和hexa-hexa-）的区域选择性合成1,3,5-triens）或4,5-dihydro-1 H-吡唑类化合物的收率很高。反应路径受烯酮中取代基的特性控制：吡唑是从包含五元杂芳族取代基的底物与芳基肼和4,5-二氢-1 H的反应获得的-吡唑由1，5-二苯基戊-1-en-4-yn-3-one与芳基肼一致地反应获得。尽管存在取代基，但是2-羟基苯并吡啶与所有检查的交叉共轭烯酮的环缩合导致吡唑的形成。该反应不需要特殊的条件（温度，催化剂，惰性气氛）。环缩合途径由底物中富电子的五元杂芳族环的电子效应决定。该合成允许在乙炔酮和肼中使用各种取代基和官能团。本方法的特征是高产率和产物纯化的简便性。所获得的吡唑具有荧光性质，量子产率高达31％。

"点击查看英文标题和摘要"

Reactivity of Cross-Conjugated Enynones in Cyclocondensations with Hydrazines: Synthesis of Pyrazoles and Pyrazolines

The cyclocondensation of cross-conjugated enynones, dienynones, and trienynones (easily available due to low-cost starting compounds) with arylhydrazines leads to the regioselective synthesis of pyrazole derivatives (dihetaryl-substituted ethens, buta-1,3-diens, and hexa-1,3,5-triens) or results in 4,5-dihydro-1H-pyrazoles in good yield. The reaction path is controlled by the character of the substituent in enynone: the pyrazoles are obtained from the reaction of substrates that contain five-membered heteroaromatic substituents with arylhydrazines, and the 4,5-dihydro-1H-pyrazoles are obtained from the reaction of 1,5-diphenylpent-1-en-4-yn-3-one with arylhydrazines consistently. Despite the presence of a substituent, cyclocondensation of 2-hydrazinylpyridine with all of examined cross-conjugated enynones leads to the formation of pyrazoles. The reaction does not require special conditions (temperature, catalyst, inert atmosphere). The cyclocondensation pathways are determined by the electronic effect of an electron-rich five-membered heteroaromatic ring in the substrate. The synthesis allows use of various substituents and functional groups in enynone and hydrazine. The present method features high yields and simplicity of the product purification. The obtained pyrazoles possess fluorescent properties with a quantum yield up to 31%.

更新日期：2021-05-22

点击分享查看原文

点击收藏

阅读更多本刊新发论文