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The present work describes an efficient and environmentally benign four component synthesis of structurally diverse substituted pyrido-pyrimidines involving the reaction of barbituric acid, 4-hydroxy 6-methyl 2-pyrone, an aromatic aldehyde and ammonium acetate in low transition temperature mixture (LTTM) (glycerol:proline: 1:1). The LTTM serves as green solvent which is an inexpensive, nontoxic and plays a dual function (reusable catalyst and solvent), and is found to be an excellent reaction endorsing medium. The present protocol offers some advantages such as easy work up, shorter reaction time, an excellent yield with higher atom economy, maximum reaction efficiency with an excellent green chemistry metrics. The synthesized compounds have been evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay as well as molecular docking studies performed on myeloperoxidase enzyme. Tested scaffolds exhibits an excellent results of virtual screening and antioxidant activity. [ABSTRACT FROM AUTHOR]

In the present work, the catalytic potential of natural organocatalyst thiamine hydrochloride is explored for the synthesis of 1,2,4‐triazolidine‐3‐thiones in aqueous medium. The reaction of thiosemicarbazides with various substrates viz aryl/ heteroaryl aldehydes, isatins, cyclic and aromatic ketones to obtain corresponding 1,2,4‐triazolidine‐3‐thiones have been successfully demonstrated for the first time. The method proposed in this work addresses the green chemistry principles such as biodegradable catalyst, ambient reaction condition, shorter reaction time, high yield of the products, recyclability of catalyst and high atom economy. [ABSTRACT FROM AUTHOR]

An efficient green protocol has been investigated for the synthesis of pyrimido[4,5-b]quinolines derivatives via one-pot three-component condensation of 4-chloro aniline, aromatic aldehyde and barbituric acid using low transition temperature mixtures as new generation and sustainable solvents. The process was accomplished with the use of greener and recyclable reaction media, simple methodology, easy workup procedures and no chromatographic purification with high yield. This new approach is expected to discover some significance in combinatorial synthesis of biologically active scaffolds. Graphical Abstract: [ABSTRACT FROM AUTHOR]

The expansion of proficient and environmentally benign synthetic protocols has engrossed increasing attention in recent organic syntheses in view of the mounting concern over the environment. As part of this green concept, our group designed novel LTTM by using Glycerol and proline (1:1) at reflux condition, and effectiveness of novel DES or LTTM has been studied for the synthesis of 7-(aryl)-10-methyl-6 H ,7 H -chromeno[4,3- d ]thiazolo[3,2- a ]pyrimidin-6-one derivatives via Multicomponent reaction. The synthetic methodology with the use of novel LTTM as green solvent and inexpensive, biodegradable, plays a dual role (recyclable catalyst and solvent) with its operational simplicity and maximum greener synthetic efficiency with green chemistry metrics calculations will be attractive for academic and industrial research. The synthesized derivatives have been evaluated for mosquito larvicidal bioassay using two mosquito species namely Aedes aegypti and Culex quinquefasciatus. Unlabelled Image • New entry of DES or LTTM. • Products with excellent yield with non-chromatographic purification, shorter reaction time. • Successively reused LTTM on the basis of Green chemistry. • Admirable green metric correlation with synthesized scaffolds with high atom economy. • Synthesized derivatives exhibit an excellent mosquito larvicidal activity. [ABSTRACT FROM AUTHOR]

Product formation in this efficient, green, three-component one-pot reaction is simply controlled by the sequence of addition. [ABSTRACT FROM AUTHOR]