尽管吡咯并[1,2-a]喹喔啉在药物研究和有机合成中很重要,但这些化合物的多样化仍然受到限制。本文中,我们开发了一种选择性氯化4-芳基吡咯并[1,2-a]喹喔啉中的C 1 H键的方法。反应在作为氯化剂的NCS,催化量的DMSO和作为溶剂的CHCl 3的存在下进行。包括氟,氯和甲硫基在内的各种官能团与反应条件相容。位于吡咯并[1,2-a]喹喔啉(例如呋喃,噻吩或吡啶)的C4位的杂环也与反应条件兼容。在作为溴化剂CuBr 2的存在下,吡咯并[1,2-a]喹喔啉的溴化成功2 S 2 O 8作为氧化剂,甲苯作为溶剂。
由于氢化产物的脱氢重新芳构化和氮原子的中毒作用,多环含氮杂芳族化合物的不对称氢化仍然是一个巨大的挑战。这里,通过在原位用乙酸酐来抑制rearomatization和中毒效果,多环含氮杂的新型铱-催化的对映选择性氢化的氢化产物保护-吡咯并/吲哚并[1,2一]喹喔啉和菲啶-已经成功可以轻松获得高达98%ee的手性二氢吡咯并/吲哚并[1,2- a ]喹喔啉和二氢菲啶。该策略具有广泛的底物范围,易于操作和潜在的医学应用。
Elemental Sulfur Mediated Synthesis of Pyrrolo[1,2-a]quinoxalines from 1-(2-Nitroaryl)pyrroles
作者:Tung T. Nguyen、Nam T. S. Phan、Tuan H. Ho、Nhu T. A. Phan、Thuyen T. C. Ho、Duyen L. M. Tran
DOI:10.1055/a-1534-0466
日期:2021.11
Methods to afford pyrrolo[1,2-a]quinoxalines often require the use of prefunctionalized aniline precursors, transition metals, and/or harsh conditions. Herein we describe a simple coupling of 1-(2-nitroaryl)pyrroles and arylacetic acids, in the presence of elemental sulfur, to furnish the fused heterocycles in good yields. The conditions are compatible with many functionalities including ester, nitrile
Lewis Acid-Catalyzed Selective Synthesis of Diversely Substituted Indolo- and Pyrrolo[1,2-a]quinoxalines and Quinoxalinones by Modified Pictet-Spengler Reaction
作者:Akhilesh K. Verma、Rajeev R. Jha、V. Kasi Sankar、Trapti Aggarwal、Rajendra P. Singh、Ramesh Chandra
DOI:10.1002/ejoc.201101013
日期:2011.12
An efficient tandem process for the selectivesynthesis of 1,2-annulated α-fused quinoxalines using benzotriazole methodology by a modifiedPictet–Spenglerreaction is described. The approach involves the reaction of arylamines 4 with aromatic aldehydes 5 to furnish 6-endo-dig-cyclized products. Dihydroquinoxalines 6 were selectively obtained by using AlCl3 in tetrahydrofuran (THF) at room temperature
Direct Synthesis of Pyrrolo[1,2-α]quinoxalines <i>via</i> Iron-Catalyzed Transfer Hydrogenation between 1-(2-Nitrophenyl)pyrroles and Alcohols
作者:Simin Chun、Jiwon Ahn、Ramachandra Reddy Putta、Seok Beom Lee、Dong-Chan Oh、Suckchang Hong
DOI:10.1021/acs.joc.0c02145
日期:2020.12.4
Herein, we describe novel iron-catalyzed transferhydrogenation between alcohols and 1-(2-nitrophenyl)pyrroles for the synthesis of pyrrolo[1,2-α]quinoxalines. The tricarbonyl (η4-cyclopentadienone) iron complex catalyzed the oxidation of alcohols and the reduction of nitroarenes, and the corresponding aldehydes and aniline were generated in situ. The resulting Pictet–Spengler-type annulation/oxidation
Driving Recursive Dehydration by P<sup>III</sup>/P<sup>V</sup> Catalysis: Annulation of Amines and Carboxylic Acids by Sequential C–N and C–C Bond Formation
作者:Morgan Lecomte、Jeffrey M. Lipshultz、Shin-Ho Kim-Lee、Gen Li、Alexander T. Radosevich
DOI:10.1021/jacs.9b06277
日期:2019.8.14
A method for the annulation of amines and carboxylicacids to form pharmaceutically relevant azaheterocycles via organophosphorus PIII/PV redox catalysis is reported. The method employs a phosphetane catalyst together with a mild bromenium oxidant and terminal hydrosilane reductant to drive successive C–N and C–C bond-forming dehydration events via the serial action of a catalytic bromophosphonium
Efficient synthesis of pyrrolo[1,2-a]quinoxalines catalyzed by a Brønsted acid through cleavage of C–C bonds
作者:Caixia Xie、Lei Feng、Wanli Li、Xiaojun Ma、Xinkun Ma、Yihan Liu、Chen Ma
DOI:10.1039/c6ob01401a
日期:——
An efficient and convenient one-pot domino reaction for the direct synthesis of pyrrolo[1,2-a]quinoxalines has been developed. This approach utilizes an imine formation reaction, SEAr reaction and cleavage of C–C bonds catalyzed by a Brønsted acid. β-Diketones and β-keto esters are both well tolerated to give the corresponding products in moderate to excellent yields.
已经开发了用于直接合成吡咯并[1,2- a ]喹喔啉的有效且方便的一锅多米诺反应。该方法利用用于形成亚胺的反应,S È氩反应和裂解由布朗斯台德酸催化的C-C键。β-二酮和β-酮酯均具有良好的耐受性,可以以中等至极好的收率得到相应的产物。