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

An effective one-pot strategy was developed for the synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones from pyrazolo[3,4-b]pyridin-6-ones, obtained by reacting 5-aminopyrazoles with 4-arylidene-2-phenyloxazol-5(4H)-ones (azlactones) under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium (t-BuOK/DMSO). The fluorescent properties of the synthesized compounds were studied. 4-Arylpyrazolo[3,4-b]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.

Novel Approach to the Synthesis of 3-amino-4-arylpyridin-2(1H)-one Derivatives.

The reaction of 4-arylidene-2-phenyloxazol-5(4H)-ones with enamines of ethyl acetoacetate gave 4-aryl-2-methyl-6-oxo-5-[(phenylcarbonyl)amino]-1,4,5,6-tetrahydropyridine-3-carboxylic acid esters, which, when heated with phosphorus oxychloride, were converted into esters of 7-aryl-5-methyl-2-phenyloxazolo[5,4-b]pyridine-6-carboxylic acids. Alkaline hydrolysis of these compounds gave 4-aryl-2-methyl-6-oxo-5-[(phenylcarbonyl)amino]-1,6-dihydropyridine-3-carboxylic acid esters. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10593-021-02980-w.