Unprecedented SnCl2-Mediated Cyclization of Nitro Arenes via N−N Bond Formation
摘要:
A mild, efficient, one-pot protocol for the cyclization of nitro-aryl substrates using SnCl2 has been described. The mechanistic course of the reaction suggests the involvement of a hydroxylamine intermediate leading to an intramolecular cyclization via N-N bond formation. The versatility of the methodology has been demonstrated by using two nitro-aryl substrates derived from dihydroisoquinolines and dihydro-beta-carbolines. The intramolecular cyclization led to the formation of indazoles in high yields and purities.
Iodine-catalyzed chemoselective dehydrogenation and aromatization of tetrahydro-β-carbolines: A short synthesis of Kumujian-C, Eudistomin-U, Norharmane, Harmane Harmalan and Isoeudistomine-M
作者:Sunil Gaikwad、Dayanand Kamble、Pradeep Lokhande
DOI:10.1016/j.tetlet.2018.04.043
日期:2018.6
Temperature controlled chemoselective dehydrogenation and aromatization of tetrahydro-β-carbolines, using molecular I2 and H2O2, in DMSO solvent affords a practical access to a series of corresponding 3,4-dihydro-β-carbolines and β-carbolines respectively. This method has been successfully employed in the short synthesis of Kumujian-C, Eudistomin-U, Norharmane Harmane Harmalan and Isoeudistomin-M.
在DMSO溶剂中使用分子I 2和H 2 O 2对四氢-β-咔啉进行温度控制的化学选择性脱氢和芳构化,可分别实际获得一系列相应的3,4-二氢-β-咔啉和β-咔啉。该方法已成功用于Kumujian-C,Eudistomin-U,Norharmane Harmane Harmalan和Isoeudistomin-M的短合成中。
Microwave Assisted Pictet–Spengler and Bischler–Napieralski Reactions
作者:Bikash Pal、Parasuraman Jaisankar、Venkatachalam S. Giri
DOI:10.1081/scc-120021516
日期:2003.1.7
Abstract Pictet–Spengler and Bischler–Napieralskireaction products have been prepared–using microwave irradiation on silicagel support under solvent free condition. Microwave assisted reactions have resulted in better yields of the desired products than prepared under conventional conditions.
An efficient and convenient synthesis of heterocycle-fused indazoles via the N–N bond forming reaction of nitroarenes induced by low-valent titanium reagent
作者:Wei Lin、Ming-Hua Hu、Xian Feng、Cheng-Pao Cao、Zhi-Bin Huang、Da-Qing Shi
DOI:10.1016/j.tet.2013.05.074
日期:2013.8
A mild and efficient one-pot protocol for the preparation of 8,13-dihydro-7H-indolo[2′,3′:3,4]pyrido[1,2-b]indazole and 5,6-dihydroindazolo[3,2-a]isoquinoline via the reductive cyclization of nitro-aryl substrates mediated by a low-valent titanium reagent has been developed. The attractive features of the current method include an N–N bond formation and the selective reduction of the CN bond and nitro
一种温和有效的一锅法制备8,13-dihydro-7 H-吲哚并[2',3':3,4]吡啶并[1,2- b ]吲唑和5,6-二氢吲唑[3]已经开发了通过低价钛试剂介导的硝基-芳基底物的还原环化形成的2-2- α ]异喹啉。当前方法的吸引人的特征包括N–N键的形成以及C N键和硝基的选择性还原,通过控制反应混合物的pH值,一锅即可轻松实现。