Multicomponent Coupling Cyclization Access to Cinnolines via in Situ Generated Diazene with Arynes, and α-Bromo Ketones
作者:Wen-Ming Shu、Jun-Rui Ma、Kai-Lu Zheng、An-Xin Wu
DOI:10.1021/acs.orglett.5b03236
日期:2016.1.15
A transition-metal-freemulticomponent coupling cyclization reaction was explored involvingarynes, tosylhydrazine, and α-bromo ketones. The reaction proceeds via a formal [2 + 2 + 2] cycloaddition, giving access to cinnoline derivatives in moderate yields under mild conditions. Three chemical bonds were formed—two C–N bonds and one C–C bond—in a single step.
excellent yields. The salient features of this reaction include readily available starting materials, good functional group compatibility, mild reaction conditions, no column chromatography, high bond-formation efficiency, and ease in further transformations. Notably, this is the first example for the synthesis of 2H-indazoles with in situ generated diazoniumsalt as the nitrogen source, and a mechanistic
Facile cyclization of 2-arylethynyl aniline to 4(1H)-cinnolones: a new chemodosimeter for nitrite ions
作者:Raju Dey、Tanmay Chatterjee、Brindaban C. Ranu
DOI:10.1016/j.tetlet.2010.11.098
日期:2011.1
2-Arylethynyl anilines undergo very fast reaction (5 min) with nitrite ions in aqueous acidic media to produce 4(1H)-cinnolones which exhibit yellow color and UV absorbance at 391 nm. This reaction is irreversible and has been successfully tested for the detection of nitrite ions in water at ppm concentration. Thus, 2-phenylethynyl aniline serves as a chemodosimeter. An efficient and general method
The Richter reaction in the synthesis of combretastatin analogs
作者:A. A. Babushkina、V. N. Mikhailov、A. D. Ogurtsova、A. S. Bunev、V. N. Sorokoumov、I. A. Balova
DOI:10.1007/s11172-023-3866-3
日期:2023.4
The regioselectivity of the Richter cyclization for a series of 4-halo-2-[(3,4,5 trimethoxyphenyl)ethynyl]anilines has been studied to obtain trimethoxybenzoyl-1H-indazoles, heteroanalogs of combretastatin. In aqueous acetonitrile, cinnolin-4(1H)-ones, which are products of 6-endo-dig cyclization, are formed along with 1H-indazoles, products of 5-exo-dig cyclization. In a DMSO:H2O mixture, 3-aroyl-1H-indazoles
Synthesis of trifluoroethoxy/aryloxy cinnolines, cinnolinones and indazoles from <i>o</i>-alkynylanilines <i>via</i> metal-free diazotization reagent
作者:Madan Kumar、Avijit Goswami
DOI:10.1039/d4ob00058g
日期:——
and user-friendly protocol for the synthesis of trifluoroethoxy/aryloxy cinnolines, cinnolinones and indazoles from o-alkynylaniline in good-to-excellent yields has been developed using a metal-free diazotization reagent (a combination of BF3·OEt2 and TBN). The methodology has been further extended to construct bis-cinnolinones and for the chemoselective synthesis of N-propargylated cinnolinones.