Synthesis of N-Acyl Triazolyl-Pyrazolines via Acylation Initiated by the Hydrazone Moiety with Carboxylic Acids

An efficient synthesis of N-acyl/N-substituted acyl pyrazolines and their triazole hybrids have been accomplished via acylation of pyrazolines and pyrazoline-triazole hybrids with carboxylic acids and/or substituted carboxylic acids in the absence of activating agents/catalysts. In the present study, a mechanism envisaging the in situ generation of a new transient acylating intermediate has been proposed to explain the acylation.     

The First One‐Pot,Solvent‐Free,Microwave‐Accelerated,Three‐Component Synthesis of Spirothiazolidin‐4‐ones via Staudinger/Aza‐Wittig Coupling/Cyclization

An efficient and rapid, solvent‐free, microwave‐accelerated, one‐pot, three‐component protocol for the synthesis of spirothiazolidin‐4‐ones from organic azides is reported for the first time via Staudinger/aza‐Wittig coupling/cyclization. The solvent‐free approach overcomes the limitations associated with the prevailing solution‐phase methodologies in the case of amines. In particular, its novelty is that it eradicates the vital limitation, i.e., the accumulation of H₂O (by‐product), which is known to affect the yield and rate of the reaction, thus affording the spirothiazolidin‐4‐ones in short reaction times in excellent yields.     

Chemoselectivity in Coupling of Azides with Thioacids in Solution-Phase and Solvent-Free Conditions

Solvent-free rapid coupling of monothiocarboxylic acid with azide affords carboxamide chemoselectively. Triphenyl phosphine included as an additive influences the chemoselectivity, yielding carboxamide and thioamide. Similar variation in the chemoselectivity is observed in the absence and presence of triphenyl phosphine in solution-phase methodology. Rapidity and ecofriendliness of the solvent-free approach to yield the products in just 15 min is noteworthy compared to the solution-phase protocol, which has a long reaction time (1–3 days).     

The First Solvent‐Free,Microwave‐Accelerated,Three‐Component Synthesis of Thiazolidin‐4‐ones via One‐Pot Tandem Staudinger/aza‐Wittig Reaction

An efficient and rapid, solvent‐free, microwave‐accelerated, one‐pot, three‐component protocol for thiazolidin‐4‐ones synthesis from organic azides has been reported for the first time via Staudinger/aza‐Wittig reaction. The microwave‐accelerated, solvent‐free approach overcomes the limitations associated with the prevailing solution phase methodologies. In particular, its novelty is that it eradicates the vital limitation, that is, accumulation of water (byproduct) that is known to affect the yield and rate of the reaction. Thus, a library of thiazolidin‐4‐ones has been synthesized in short time in excellent yields (92–96%).     

An effcient and facile synthesis of novel 1,2,3-triazolyl-N- acylpyrazoline hybrids简

An efficient and facile synthesis of a library of hitherto novel 1,2,3-triazolyl-N-acetyl/N-propionylpyrazoline hybrids(16 examples) in excellent yields(90%–96%) has been accomplished from easily accessible 1,2,3-triazolyl chalcone precursors.     

An eco-friendly water mediated synthesis of 1,2,3-triazolyl-2- aminopyrimidine hybrids as highly potent anti-bacterial agents

An elegant and efficient synthesis of novel 1,2,3-triazole fused 2-aminopyrimidine hybrids has been accomplished for the first time in the green solvent viz. water. The hybrid molecules exhibit significant anti-bacterial activity when screened against three human pathogens viz. Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. In comparison to the commercially marketed drug tetracycline, some of them are equally potent and a few are more potent.     

Solvent-free protocol for amide bond formation via trapping of nascent phosphazenes with carboxylic acids

A solvent-free synthesis of amides via the coupling of phosphazenes with carboxylic acids is reported. Increasing the rate of heating either by microwave irradiation or conventional heating results in multifold increase in the rate of amide bond formation. Synthesis of a library of amides including a potent antitumour candidate has been accomplished.