Heterocyclization of 3-(R-amino)-3-methylthio-1-phenylpropenones and 5-benzoyl-6-methylthio-1,2-dihydropyridin-2-ones with 1,2- and 1,3-dinucleophilic reagents

Abstract

Keywords: 1-alkyl-5-benzoyl-3-ethoxycarbonyl-6-methylthio-1,2-dihydropyridin-2-ones, 6-amino-5-benzoyl-3-ethoxycarbonyl-1-methyl-1,2-dihydropyridin-2-one, 3-(R-amino)-3-methylthio-1-phenylpropenones, 1-R 1 -5-(R-amino)-3-phenylpyrazoles, benzimidazo[1,2-a]pyridines, benzimidazo[1,2-a]-pyrimidines, 6,7-dihydro-2H-pyrazolo [3,4-b]pyridines, 1,2,4-triazole, [1,2,4]triazolo[4,3-b]pyridazines, heterocyclization, [3+2] and [3+3] cyclocondensations.3-Alkylthio-3-(R-amino)-1-arylpropenones may react both with electrophilic and with nucleophilic and polycentered reagents. As a result of this they are desirable starting materials for the synthesis of nitrogencontaining heterocycles, derivatives of pyrimidine, pyrrole, pyridine, isoxazole, and quinoline [1][2][3][4][5]. In reactions with nucleophiles these substrates react at two reaction centers, at the carbonyl group and at C-3 [5]. The relative ease of carrying out such heterocyclizations is caused by the good nucleofugicity of the alkylthio group of 3-alkylthio-3-(R-amino)-1-aryl-propenones. In addition the presence of competing reaction centers may lead to nonselectivity in the execution of reactions of 3-alkylthio-3-(R-amino)-1-aryl-propenones with unsymmetrical dinucleophiles. It should be mentioned that, with the exception of [5], no investigations have been carried out in this area.