Pyrazoles are very important class of biologically active compounds and many of their derivatives are in clinical use. Pyrazole derivatives have been shown to exhibit antihyperglycemic [1], hypoglycemic [2] and fungicidal properties [3]. Some of them are also used as insecticides and herbicides [4,5]. Of the condensed pyrazoles, specially pyrano[2,3-c]pyrazole is a fused heterocycle comprising ...

A new, simple thermally efficient and solvent-free condensation of 2-amino-3-cyano-6-methyl-4-phenyl-4H-pyran-5-ethylcarboxylate derivatives with coumarin-3-carboxylic acid employing pentafluorophenylammonium triflate (PFPAT) as an inexpensive organocatalyst for the synthesis of a series of ethyl 4,5-dihydro 7-methyl-2-(2-oxo-2H-chromen-3-yl)-4-oxo-5-aryl-3H-chromeno[2,3-d]pyrimidine-6-carboxyl...

An environment friendly synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran, 2aryl benzimidazole and 2-aryl-4, 5-dihydro-1H-imidazole derivatives using Mg-Al hydrotalcite as an efficient catalyst has been developed. The excellent efficiency of the catalyst can be attributed to its Lewis acidic sites which resulted in higher reaction yields for different sub...

Two high-yielding strategies for the synthesis of 4H-anthra[1,2-b]pyran antibiotics have been developed giving access to novel antitumor agent (ED(50) 1.5 microm) and to (S)-espicufolin (3). A key step for the assembly of the tetracyclic 4H-anthra[1,2-b]pyran-4,7,12-trione skeleton is the nucleophilic addition of an aryl lithium species onto an aldehyde which allows the introduction of either a...