FeCl3·6H2O-catalyzed facile and efficient synthesis of pyrano[4,3-b]quinolines and isochromenes
作者:Mrityunjaya Asthana、Jay Bahadur Singh、Radhey M. Singh
DOI:10.1016/j.tetlet.2015.12.102
日期:2016.2
developed for the synthesis of 1,3-disubstituted 1H-pyrano[4,3-b]quinolines from o-arylethnylquinonylmethanol via 6-endo-dig cyclization of alcoholic –OH onto alkynes in good to excellent yields. The reaction conditions were successfully exploited on primary and tertiary alcohol analogs. The reagent was further generalized with the aromatic alcohol analogs providing the synthesis of isochromenes in
廉价的1摩尔%的FeCl 3 ·6H 2 ö试剂已经被用于合成开发1,3-二取代1 ħ吡喃并[4,3- b ]喹啉由ö经由6 -arylethnylquinonylmethanol -内将醇-OH环化成良好至优异收率的炔烃。反应条件已成功地用于伯醇和叔醇类似物。该试剂进一步用芳族醇类似物泛化,从而以高收率合成了异色烯。从伯醇到仲醇到叔醇的反应速率和产率的提高可以归因于烷基的诱导作用,其增强了羟基的亲核性并加速了环化模式。
Metal-free POCl<sub>3</sub> promoted stereoselective hydrochlorination of ethynylated azaheterocycles
作者:Ritush Kumar、Radhey M. Singh
DOI:10.1039/c9ob00841a
日期:——
POCl3 as a chlorinating agent under metal-free reaction conditions. Mechanistic studies show that the reaction proceeded via nucleophilic attack of POCl3 on the nitrogen of the quinoline ring in a stereoselective manner. The resulting products were versatile intermediates in organic synthesis and were used in the cross-coupling reaction and metal-free synthesis of heterocycles. The developed protocol features
Cu(I)-Catalyzed Oxygen and Nitrogen Nucleophiles Triggered Regioselective Synthesis of Furo/Pyrrolo-Annulated Quinolines
作者:Ritush Kumar、Atish Chandra、Bilal Ahmad Mir、Gaurav Shukla
DOI:10.1021/acs.joc.9b00662
日期:2019.9.6
Cu(I)-catalyzedintramolecularannulation of o-ethynylquinoline-3-carbaldehydes leads to the synthesis of alkoxy/imidazole-substituted 1,3-dihydrofuro[3,4-b]quinolines via C–O and C–N bond formation. The scope of the reaction was further extended to o-ethynylquinoline-3-carbonitriles for the synthesis of alkoxy-substituted 3H-pyrrolo[3,4-b]quinolines using alcohols as nucleophiles. These reactions
Cu(I) 催化的o -ethynylquinoline-3-carbaldehydes 的分子内环化导致通过 C-O 和 C-N 键的形成合成烷氧基/咪唑取代的 1,3-二氢呋喃[3,4- b ] 喹啉。该反应的范围进一步扩展到邻乙炔基喹啉-3-腈,用于使用醇作为亲核试剂合成烷氧基取代的 3 H-吡咯并[3,4- b ]喹啉。这些反应区域选择性地有利于所有环化过程中的 5 -exo-dig环化。
Catalytic trifluoromethylation of aldehyde and potential application for pyrano[4,3-b]quionline synthesis
作者:Kalpana Mishra、Kishor Chandra Bharadwaj、Radhey M. Singh
DOI:10.1016/j.tetlet.2018.08.012
日期:2018.9
heteroaromatic aldehydes at room temperature to afford trifluoromethyl group containing alcohols in very good yields. Using catalytic amount of CsF (0.2 eq.) in toluene, trifluoromethylated products were achieved in good yields at rt. The substrate scope has been exemplified by a large number of substrates. As an application, iodo etherification/cyclization has also been demonstrated for the synthesis of trifluoromethyl
我们已经描述了在室温下CsF催化的杂芳族醛的三氟甲基化以非常好的收率得到含三氟甲基的醇。使用在甲苯中的催化量的CsF(0.2当量),在室温下以良好的产率获得了三氟甲基化的产物。基板范围已经以大量基板为例。作为一种应用,碘醚化/环化也已被证明可以非常好地由邻炔基三氟甲醇合成三氟甲基吡喃并[4,3- b ]喹啉。
An economical nucleophilic route toward facile synthesis of pyrano[4,3-b]quinolin-1-ones via 6-endo-dig cyclization of o-alkynylquinoline esters
作者:Neha Sharma、Mrityunjaya Asthana、Durgesh Nandini、R.P. Singh、Radhey M. Singh
DOI:10.1016/j.tet.2012.12.068
日期:2013.2
Metal-free facile synthesis of pyrano[4,3-b]quinoline-1-ones is described from methyl 2-arylethynyl-quinoline-3-carboxylates via intramolecular cyclization in excellent yields. The cyclization reactions are facilitated using cheap and easily available KOH base in MeOH. The reaction conditions did not require dry solvent, inert atmosphere, and avoid further column chromatography purification of the products. These compounds could be further used as building blocks for the synthesis of 2H-benzo[b][1,6]naphthyridin-1-one and 1-chloro-benzo[b][1,6]naphthyridines. (C) 2013 Elsevier Ltd. All rights reserved.