Cyclization of 2-dicyanomethylene-1,2-dihydropyridine-3-carbonitriles with amines: a mechanistic rationalization
摘要:
A mechanistic rationalization for the cyclization of the 1,5-dinitrile system present in pyridines 4{1-3} with amines to lead to 1,6-naphthyridines is proposed. Three factors play an important role on the direction of cyclization: (1) the cyclization involves nucleophilic attack of an amidine onto a nitrile or amidine; (2) the attack has to fulfill strict geometrical constraints to allow the cyclization to proceed; (3) the cyclization step should involve the nucleophilic attack combined with a tautomerism to achieve the high levels of regioselectivity observed. (c) 2006 Elsevier Ltd. All rights reserved.
Cyclization of 2-dicyanomethylene-1,2-dihydropyridine-3-carbonitriles with amines: a mechanistic rationalization
作者:Francisco Carrión、Núria Mont、Xavier Batllori、José I. Borrell、Jordi Teixidó
DOI:10.1016/j.tet.2006.10.025
日期:2007.1
A mechanistic rationalization for the cyclization of the 1,5-dinitrile system present in pyridines 41-3} with amines to lead to 1,6-naphthyridines is proposed. Three factors play an important role on the direction of cyclization: (1) the cyclization involves nucleophilic attack of an amidine onto a nitrile or amidine; (2) the attack has to fulfill strict geometrical constraints to allow the cyclization to proceed; (3) the cyclization step should involve the nucleophilic attack combined with a tautomerism to achieve the high levels of regioselectivity observed. (c) 2006 Elsevier Ltd. All rights reserved.