Green synthesis of novel hexahydroquinolines and 6-amino-2-oxopyridine-3,5-dicarbonitriles incorporating sulfaguanidine via [3 + 3] atom combination

The synthesis of sulfa drugs has received extensive interest from researchers for their broad spectrum of biological activities. In this context, N -Carbamimidoyl-4-((5,5-dimethyl-3-oxocyclohex-1-en-1-yl)amino)benzenesulfonamide 3 was readily prepared and its Michael addition reactions towards activated cinnamonitriles were studied as a route to 4-(2-amino-3-cyano-4-aryl-tetrahydroquinolin-1-yl)- N -carbamimidoylbenzenesulfonamide derivatives 8a-d . Moreover, N -(4-( N -carbamimidoylsulfamoyl)phenyl)-2-cyanoacetamide 13 was prepared and employed as a precursor for the synthesis of 4-(6-amino-3,5-dicyano-2-oxo-4-arylpyridin-1-yl)- N -carbamimidoylbenzenesulfonamide derivatives 17a-e . Green synthesis of the targeted products was done in water in the presence of chitosan as a green catalyst and gave considerably higher yields as compared to conducting reactions in ethanol in presence of non-benign piperidine catalyst. The chemical constitution of all newly synthesized compounds was confirmed by the different spectral tools.