Chitosan as a green catalyst for synthesis of pyridazines and fused pyridazines via [3+3] atom combination with arylhydrazones as 3 atom components

Abstract

A series of arylhydrazones 1a-c were prepared and reacted with α,β-unsaturated nitriles 2a-e to yield 1,4-dihydropyridazines and fused pyridazinoquinazoline. The prepared pyridazines and fused pyridazines are then used as precursors for synthesis of polycondensed pyridazine ring systems.

Synthesis of novel bis(dihydropyridine) and terpyridine derivatives

“…[22][23][24][25][26] Although the synthesis of biologically interesting 1,2dihydropyridine-3,5-dicarbonitrile derivatives has been investigated in the past, [27][28][29][30][31] there is still demand for more concise and efficient elucidation of molecular structure. In connection with this finding and in continuation to our work on Michael addition, [32][33][34][35][36][37][38] multicomponent reactions, [35][36][37][39][40][41][42][43][44][45] as well as on the synthesis of bis-heterocycles, 41,[45][46][47][48][49][50][51][52][53][54] we report herein on the synthesis of novel bis(1,2-dihydropyridine-3,5dicarbonitriles) and terpyridines utilizing 2-cyanoacetamide derivatives as intermediates.…”

N-(Pyrazol-5-yl)cyanoacetamide in heterocyclic synthesis: synthesis of novel N-(pyrazol-5-yl)pyridine-3,5-dicarbonitrile, pyrazolo[1,5-a]pyrido[3,2-e]pyrimidine-7-carbonitrile and pyrazolo[4,3-e]pyrido[1,2-a]pyrimidine-6,8-dicarbonitrile moieties

“…[3][4][5][6] Moreover, pyridine derivatives have attracted a continuing interest over the past years as they exhibit diverse biological activities that include antihistaminic, 7 antihypertensive, 8 antiviral, 9,10 antitumor, 11,12 and anti-inflammatory agents. 13 Encouraged by the above findings and as a part of an ongoing research program on Michael addition reaction to acrylonitrile derivatives [14][15][16][17][18][19][20][21][22][23][24][25][26] we report herein the results of our investigations concerning the different reactivity patterns of 7-aminopyrazolo [1,5a]pyrimidin-5-one and cyanoacetamides towards cinnamonitrile derivatives.…”

Bis(2-cyanoacetamides): versatile precursors for bis(dihydropyridine-3,5-dicarbonitriles)

“…Furthermore, bis-heterocycles have interesting biological properties [21][22][23] including antitumor activities, 24,25 antihypertensive, 24,26 and antiallergenic. 27 As a part of an ongoing research program on Michael addition reactions, [28][29][30][31][32][33][34][35] bis(heterocycles) [36][37][38][39][40][41][42][43][44][45][46] we report herein, the results of our investigations concerning the different reactivity patterns of bis(cyanoacetamides) containing thioether linkage towards cinnamonitrile derivatives.…”