Kumkum Kumari

A Direct Metal-Free Decarboxylative Sulfono Functionalization (DSF) of Cinnamic Acids to α,β-Unsaturated Phenyl Sulfones

A metal-free room temperature decarboxylative cross-coupling between cinnamic acids and arylsulfonyl hydrazides has been realized for the first time for the synthesis of (E)-vinyl sulfones. The scope and versatility of the reaction has been demonstrated by the regio- and stereoselective synthesis of 22 derivatives with diverse structural features.

A simple and sustainable tetrabutylammonium fluoride (TBAF)-catalyzed synthesis of azaarene-substituted 3-hydroxy-2-oxindoles through sp3 C–H functionalization

A green, practical, and metal-free protocol for direct addition of α-and γ-alkylazaarenes to isatins has been developed via sp3 C–H functionalization in water under controlled microwave radiation. This methodology provides a mild and fast route to biologically important azaarene-substituted 3-hydroxy-2-oxindoles in good to excellent yields.

An Expeditious Synthesis of Tetrahydro-1,2,4-triazolo[5,1-b]quinazolin-8(4H)-ones and Dihydro-1,2,4-triazolo[1,5-a]pyrimidines

There is currently great interest in solid-state reactions as they offer potential reduction in environmental contamination with the elimination of solvents.1,2 One practical approach to achieve this goal is by grinding the solid reactants together using a mortar and pestle, a technique adopted for a number of reactions.3,4 One-pot multi-component reactions (MCRs) have been exploited as a powerful tool for the assembly of large libraries of biologically active compounds.5,6 Among heterocycles, quinazolinones and triazolo-pyrimidines have attracted a great deal of attention due to their therapeutic and pharmacological properties.7,8 Drugs such as fluconazole and itraconazole are notable examples of antifungal molecules possessing the triazole nucleus. In view of the above and considering the fact that ionic liquids have been used as eco-friendly catalysts as well as solvents in organic synthesis,9–13 it was thought worthwhile to utilize the catalytic potential of 1-nbutyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) in the synthesis of tetrahydro1,2,4-triazolo[5,1-b]quinazolin-8(4H)-ones and dihydro-1,2,4-triazolo[1,5-a]pyrimidines. Although different strategies have been employed for the synthesis of these compounds,14–18 these methods suffer from drawbacks such as long reaction times, cumbersome isolation of the products and harsh reaction conditions. We now report a facile and efficient ionic liquid-catalyzed multi-component synthesis of tetrahydro-1,2,4-triazolo[5,1-b]quinazolin8(4H)-ones (3) and dihydro-1,2,4-triazolo[1,5-a]pyrimidines (4) in excellent yields from 3-amino-1,2,4-triazole, aldehydes and dimedone (or ethyl acetoacetate), respectively, by simple grinding using a mortar and pestle at room temperature (Scheme 1). In order to optimize the reaction conditions, test reactions of 3-amino-1,2,4-triazole (1), benzaldehyde (2a) and dimedone were carried out in the presence of various ionic liquid catalysts. While there was no observable product in the absence of the catalyst, the addition of various [Bmim] salts, brought about a dramatic change in the reaction profile, the best result being obtained using 15 mol% of [Bmim]BF4 at room temperature in 12 min. Although it was also determined that heating at 70◦C in the presence of 15 mol%