New one-pot synthesis of 4-arylpyrazolo[3,4- <i>b</i> ]pyridin-6-ones based on 5-aminopyrazoles and azlactones

Abstract

An effective one-pot strategy was developed for the synthesis of 4-arylpyrazolo[3,4-<i>b</i>]pyridin-6-ones from pyrazolo[3,4-<i>b</i>]pyridin-6-ones, obtained by reacting 5-aminopyrazoles with 4-arylidene-2-phenyloxazol-5(4<i>H</i>)-ones (azlactones) under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium (<i>t</i>-BuOK/DMSO). The fluorescent properties of the synthesized compounds were studied. 4-Arylpyrazolo[3,4-<i>b</i>]pyridin-6-ones luminesce in the region of 409-440 nm with a quantum yield of 0.09-0.23 when irradiated with UV light.