A New Class of Pyrazolopyridine Nucleus with Fluorescent Properties, Obtained through Either a Radical or a Pd Arylation Pathway from N-Azinylpyridinium N-Aminides
摘要:
The synthesis of dipyridopyrazole and pyridopyrazolopyrazine derivatives--both of which incorporate a 3-aryl moiety--can be achieved in moderate yields by intramolecular radical arylation of pyridinium N-aminides using tris(trimethylsilyl)silane and azobisisobutyronitrile. Improved results were obtained on using Pd direct arylation in conjunction with microwave irradiation. A preliminary study into the fluorescent properties of the target compounds is also reported.
Suzuki reaction on pyridinium N-(5-bromoheteroar-2-yl)aminides
摘要:
The reactivity of substituted pyridinium N-(2'-azinyl)aminides in Suzuki-Miyaura cross-coupling reaction is reported. The reaction proceeds in good yield employing Cs2CO3 as base, and producing substitution on the negatively charged moiety. (C) 2004 Published by Elsevier Ltd.
作者:Gala, Elena、Crdoba, Marta、Izquierdo, M. Luisa、lvarez-Builla, Julio
DOI:10.3998/ark.5550190.0015.500
日期:——
Suzuki reaction on pyridinium N-haloheteroarylaminides: regioselective synthesis of 3,5-disubstituted 2-aminopyrazines
作者:Rafael Castillo、M. José Reyes、M. Luisa Izquierdo、Julio Alvarez-Builla
DOI:10.1016/j.tet.2007.11.057
日期:2008.2
An extensive study of Suzuki-Miyaura cross-coupling processes on N-pyridinium bromoazinyl aminides has been performed. Mono- and disubstitution on 5- and 3,5-bromo derivatives produced the corresponding aryl derivatives. In the disubstituted compounds regioselective substitution at the 3-position occurred, vicinal to the aminide nitrogen, and this was more evident in pyrazine derivatives. The commonly used strategy involving N-alkylation and reduction of the N-N bond gave rise to a series of 2-alkylamino-3,5-disubstituted-pyrazines. (c) 2007 Elsevier Ltd. All rights reserved.