Pyridinium N-(2′-Azinyl)Aminides: Regioselective Synthesis of 2-Alkylaminoazines

Abstract

Abstract-The regioselective alkylation of pyridinium-N-(2 H -azinil)aminides with alkyl halides under mild conditions is described. The alkylation, combined with a reduction of the N-N bond, allows an easy preparation of 2-alkylaminoazines. ᭧

Six‐Membered Heterocycles: 1,2‐, 1,3‐, and 1,4‐Diazines and Related Systems

“…Alvarez-Builla and coworkers [238] have reported methodology for selectively preparing 2-alkylaminopyrimidines 194 with high regioselectivity, after reductive removal of the pyridine moiety from the N-alkylated product (Scheme 19.216 thought to proceed through formation of an intramolecular hydrogen bond between the pyridine and pyrazine rings, which prevents alkylation of the ring nitrogens. Similar methodology can be applied to 2-aminopyrazines.…”

Pyridinium-N-(2-pyridyl)aminides and related compounds: a theoretical study

“…[1][2][3][4][5][6][7][8][9][10] These compounds belong to the class of conjugated heterocyclic Nylides. [11][12][13][14][15][16] Heterocyclic mesomeric betaines have been the subject of extensive investigation, mainly because of their 1,3-dipolar character, which allows them to take part in 1,3-dipolar cycloadditions with various dipolarophiles, thus generating novel five-membered aza heterocycles.…”

“…Amongst the rich reactivity of these compounds, Alvarez-Builla and coworkers discovered that that of azinium-N-ylides is controlled by the intramolecular hydrogenbond (HB) shown in Figure 1. 1,3,5,6 For instance, alkylation occurs exclusively on the exocyclic nitrogen atom (the N -). However, when a radical is formed, the reactivity is modified and this was attributed to a new HB between the C · and the pyridinium C-H involving a conformational change.…”

An easy preparation of pyridinium N-heteroarylaminides

“…4 -6 Moreover, N-alkylation process takes place regioselectively over the aminide nitrogen, by the partial blockage of the heteroaryl a-nitrogen, via an intramolecular hydrogen bond. 4 The N -N bond reduction of the resulting pyridinium salts should allow the preparation of the corresponding amines 4,7 or polyamines. 8 When N-alkylation was performed with a-haloesters or a-haloketones, pyrido[1,2-a]pyrimidin-4-ones and imidazo[1,2-a]pyridines were respectively obtained by a cascade heterocyclisation process.…”