A regiospecific synthesis of both positional isomers of 4,6-disubstituted 2-dicyanomethylene-1, 2-dihydropyridin-3-carbonitriles.
Mol Divers 2010;
14:755-62. [PMID:
20072813 DOI:
10.1007/s11030-009-9222-0]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 12/27/2009] [Indexed: 10/20/2022]
Abstract
A protocol allowing the regiospecific synthesis of both positional isomers of 4,6-disubstituted 2-dicyanomethylene-1,2-dihydropyridin-3-carbonitriles, precursors of 1,6-naphthyridines, is presented. Thus, treatment of enaminoketones with the propanedinitrile dimer yields one regioisomer while the treatment of the corresponding (3-chloro-allylidene)-dimethylammonium perchlorates (easily obtained from enaminoketones and POCl(3)), in which the nature of the reactive centers is inverted with respect to the enaminoketone, yields the other regioisomer.
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