Alkylation of 3,5-dichloro-2(1H)-pyrazinones using malonate esters
作者:Nigam M. Mishra、Vsevolod A. Peshkov、Olga P. Pereshivko、Sachin G. Modha、Erik V. Van der Eycken
DOI:10.1016/j.tetlet.2012.06.080
日期:2012.8
3-alkylation of 3,5-dichloro-2(1H)-pyrazinones with various malonate esters is described. The method constitutes a simple example of a C–C bond forming process at the 3-position of the pyrazinone core allowing to attain 3-substituted pyrazinones in good to high yields. 3-Alkylation of 3,5-dichloro-2(1H)-pyrazinones with acetoacetic ester was accompanied by further retro-Claisen fragmentation.
Diversely Substituted Imidazo[1,2-<i>a</i>]pyrazine-8-oxo-3-carbaldehydes: An Iodine-Mediated Cyclization/Oxidation Approach
作者:Nigam M. Mishra、Dipak D. Vachhani、Sachin G. Modha、Erik V. Van der Eycken
DOI:10.1002/ejoc.201201150
日期:2013.2
and efficient iodine-mediated intramolecular heteroannulation approach for the construction of the imidazo[1,2-a]pyrazinone core has been developed. Under ambient conditions, this metal-free protocol allows easy access to densely functionalized imidazo[1,2-a]pyrazinone-3-carbaldehydes or (aminomethyl)imidazo[1,2-a]pyrazinones from substrates containing terminal alkynes by cyclization and subsequent
Microwave-Assisted Synthesis of Pyrazino[2,1-b]quinazolines and 3-Indolyl-2(1H)-pyrazinones Employing a Chemoselective Silver(I)- and Gold(I)-Catalyzed Reaction
作者:Dipak D. Vachhani、Vaibhav P. Mehta、Sachin G. Modha、Kristof Van Hecke、Luc VanMeervelt、Erik V. Van der Eycken
DOI:10.1002/adsc.201100881
日期:2012.5.21
Novel microwave‐assisted syntheses of pyrazino[2,1‐b]quinazolines and 3‐indolyl‐2(1H)‐pyrazinones employingsilver(I)‐ or gold(I)‐catalyzed protocols have been elaborated. The scope and limitations of these processes have been investigated.