synthesis of fused pyridines by [2 + 2 + 1 + 1] the cycloaddition of ketones with an ammonium cation under a CO2 atmosphere. The reactions employed ammonium cation as a nitrogen source and CO2 gas as a carbon source in an aqueous solution. Monoethanolamine (MEA) was used as an additive to increase the solubility of CO2 in an aqueous solution. The scope and versatility of the method are demonstrated with 38
通过 [2 + 2 + 1 + 1] 酮与铵阳离子在 CO 2气氛下的环加成,探索了一种简单且绿色的合成稠合吡啶的方法。该反应在水溶液中使用铵阳离子作为氮源和CO 2气体作为碳源。单乙醇胺(MEA)用作添加剂以增加CO 2在水溶液中的溶解度。该方法的范围和多功能性通过 38 个示例进行了演示。发现产品具有光敏性,并显示出作为有机光电材料的潜在应用。在实验研究的基础上提出了一种selectfluor促进的反应机理。我们的工作非常出色,因为它是一个不含金属的系统,使用 CO 2 作为碳源和 MEA 作为水性合成中的添加剂。
A Method to Access Symmetrical Tetrasubstituted Pyridines via Iodine and Ammonium Persulfate Mediated [2+2+1+1]-Cycloaddition Reaction
作者:Weibing Liu、Hua Tan、Cui Chen、Yupeng Pan
DOI:10.1002/adsc.201601225
日期:2017.5.2
productive preparation of symmetrical 2,3,5,6‐tetrasubstituted pyridines has been developed from α‐substituted arones and N,N‐dimethyl formamide (DMF) using iodine (I2) and ammonium persulfate ((NH4)2S2O8) as mediators. In this process, both DMF and (NH4)2S2O8 play a dual role for the formation of pyridines. DMF acts as the reaction medium and the C4 source (the methyl group of DMF), while (NH4)2S2O8 serves
由α-取代的芳烃和N,N-二甲基甲酰胺开发了一种新颖的无金属[2 + 2 + 1 + 1]-环加成方法,用于快速,高效地制备对称的2,3,5,6-四取代吡啶(使用碘(I 2)和过硫酸铵((NH 4)2 S 2 O 8)作为介体。在这个过程中,DMF和(NH 4)2 S 2 O 8都对吡啶的形成起双重作用。DMF用作反应介质和C4源(DMF的甲基),而(NH 4)2 S 2 O 8用作氧化剂和氮源。值得注意的是,该转化对多种不同的芳族化合物显示出较宽的底物范围,从而以中等至优异的产率得到相应的四取代的吡啶。
Ruthenium-Catalyzed Cyclization of Ketoxime Acetates with DMF for Synthesis of Symmetrical Pyridines
A novel ruthenium-catalyzed cyclization of ketoxime carboxylates with N,N-dimethylformamide (DMF) for the synthesis of tetrasubstituted symmetrical pyridines has been developed. A methyl carbon on DMF performed as a source of a one carbon synthon. And NaHSO3 plays a role in the reaction.
Chemoselective Suzuki–Miyaura reactions on 3,5-dibromo-2,6-dichloropyridine were studied.
对3,5-二溴-2,6-二氯吡啶进行了化学选择性的Suzuki-Miyaura反应研究。
Kinetics and mechanisms of nucleophilic displacements with heterocycles as leaving groups. Part 8. Conductimetric and spectrophotometric rate constants for the reactions of pyridinium and related cations with piperidine in chlorobenzene
作者:Alan R. Katritzky、Yu Xiang Ou、Joan Ellison、Giuseppe Musumarra
DOI:10.1039/p29830001421
日期:——
which the spectrophotometric method fails. It gives equivalent results. NN′-Dimethylthiourea displaces heterocyclic leavinggroups at rates similar to those for piperidine. Compared with α-hydrogen, α-methyl groups render pyridine a less effective leavinggroup, whereas α-ethoxycarbonyl groups show a large rate enhancement.