Pyrazolo-fused 4-azafluorenones as key reagents for the synthesis of fluorescent dicyanovinylidene-substituted derivatives

Abstract

A green method for the three-component synthesis of an indeno[1,2-b]pyrazolo[4,3-e]pyridines library under microwave irradiation and their use in the preparation of novel fluorescent dicyanovinylidene-substituted derivatives is provided.

Synthesis, Photophysical Properties, and Metal-Ion Recognition Studies of Fluoroionophores Based on 1-(2-Pyridyl)-4-Styrylpyrazoles

“…In this effect, the quantum yield increases with an adequate improvement of the ICT that involves the configuration of the electronic n → π transition, while the reduction in the quantum yield due to a strong ICT is called a positive solvatokinetic effect. 25−27…”

Chemosensors based on N-heterocyclic dyes: advances in sensing highly toxic ions such as CN− and Hg2+

“…A different fused pyrazole also reported by our group is based on the pyrazolo[3,4- b ]pyridine core. 62 In this case, some strategic products of an indeno[1,2- b ]pyrazolo[4,3- e ]pyridine-5-one library having aryl groups at position 4 of the fused-ring were used as precursors of the novel dicyanovinyl substituted systems. The products were found to be tunable ICT fluorophores and could be used as chemodosimeters for the detection of CN − .…”

Recent progress in chemosensors based on pyrazole derivatives

“…15b). 150 The photophysical and computational studies of 31 showed that these products are modulable ICT uorophores, and preliminary tests revealed that these compounds could be used as uorescent chemosensors for CN À detection in both "turn-on" or "turn-off" ways. In this case, the regioisomeric addition products 31-i or 31-ii could be obtained based on their better stabilization.…”