Efficient syntheses of 1,3-unsubstituted 1H-pyrazolo[3,4-b]quinolines

Abstract

The synthesis of pyrazolo [3,4-b]quinolines from 2-chloro-3-formylquinolines is described. Direct reaction of the chloro-aldehydes with hydrazine was unsuccessful, but a very efficient sequence was developed in which protection of the aldehyde group was followed by displacement of the halogen by hydrazine, release of the aldehyde then leading to spontaneous ring closure giving the tricycles. The products were obtained in excellent yields.

Potential anti-bacterial agents: montmorillonite clay-catalyzed synthesis of novel 2-(3,5-substituted-1H-pyrazol-1-yl)-3-substituted quinolines and their in silico molecular docking studies

“…Pale yellow powder, 85% yield, mp 72-74 C (Lit. 75-76 C) 36. IR (KBr pellets, cm À1 ) n: 2921, 1626, 1541, 1330, 1101, 810 1.…”