The synthesis of 4-aryl-1H-pyrazolo[3,4-b]quino­lines by cyclization of 4-arylidenepyrazolin-5-ones with anilines

Abstract

In the reaction of anilines with 4-(benzylidene)-1,3-disubstituted pyrazol-5-ones, 1H-pyrazolo [3,4-b]quinolines were formed instead of anticipated 5-phenylimino derivatives. The same compounds were also available from the reaction of pyrazolin-5-ones with Schiff bases. In spite of moderate yields both methods present a facile route to 4-aryl-1H-pyrazolo [3,4-b]quinolines. These methods have advantages over the Friedländer cyclization commonly utilized for preparation of 4-aryl-1H-pyrazolo [3,4-b]quinolines. Thus, preparation of 2-aminobenzophenones, reagents indispensable in Friedlaender synthesis, can be avoided.

Four-Component Domino Synthesis of Pyrazolo[3,4-h]quinoline-3-carbonitriles: “Turn-Off” Fluorescent Chemosensor for Fe3+ Ions

“…In addition pyrazoloquinolines display antiviral, antibacterial, antiproliferative, and immunosuppressant activities apart from exhibiting oral antipsychotic activity in the MK-801-induced hyperactive rat model . Among the pyrazoloquinolines, the syntheses and applications of pyrazolo­[3,4- b ]­quinolone derivatives have been investigated extensively. − However, the syntheses of pyrazolo­[3,4- h ]­quinolines have received less attention . In the present work novel pyrazolo­[3,4- h ]­quinoline-3-carbonitriles have been synthesized through a one-pot, four-component domino strategy under microwave conditions.…”