1083329-56-9Relevant articles and documents
Preparation of highly reactive pyridine- and pyrimidine-containing diarylamine antioxidants
Hanthorn, Jason J.,Valgimigli, Luca,Pratt, Derek A.
experimental part, p. 6908 - 6916 (2012/10/08)
We recently reported a preliminary account of our efforts to develop novel diarylamine radical-trapping antioxidants (Hanthorn, J. J. et al. J. Am. Chem. Soc. 2012, 134, 8306-8309) wherein we demonstrated that the incorporation of ring nitrogens into diphenylamines affords compounds which display a compromise between H-atom transfer reactivity to peroxyl radicals and stability to one-electron oxidation. Herein we provide the details of the synthetic efforts associated with that report, which have been substantially expanded to produce a library of substituted heterocyclic diarylamines that we have used to provide further insight into the structure-reactivity relationships of these compounds as antioxidants (see the accompanying paper, DOI: 10.1021/jo301012x). The diarylamines were prepared in short, modular sequences from 2-aminopyridine and 2-aminopyrimidine wherein aminations of intermediate pyri(mi)dyl bromides and then Pd-catalyzed cross-coupling reactions of the amines and precursor bromides were the key steps to yield the diarylamines. The cross-coupling reactions were found to proceed best with Pd(η3-1-PhC3H 4)(η5-C5H5) as precatalyst, which gave higher yields than the conventional Pd source, Pd2(dba) 3.
A simple Cu-catalyzed coupling approach to substituted 3-pyridinol and 5-pyrimidinol antioxidants
Nara, Susheel J.,Jha, Mukund,Brinkhorst, Johan,Zemanek, Tony J.,Pratt, Derek A.
experimental part, p. 9326 - 9333 (2009/04/06)
(Chemical Equation Presented) A convenient approach to 3-pyridinols and 5-pyrimidinols via a two-step Cu-catalyzed benzyloxylation/catalytic hydrogenation sequence is presented. The corresponding 3-pyridinamines and 5-pyrimidinamines can be prepared in an analogous sequence utilizing benzylamine in lieu of benzyl alcohol. The radical-scavenging ability of these derivatives are preliminarily explored and reveal that the increased acidities of the pyridinols and pyrimidinols render them susceptible to more significant kinetic solvent effects when compared to phenols.
