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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]

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]

• Novel Merrifield resin supported [MerDABCO-BSA][HSO 4 ] 2 catalyst is synthesized. • The catalyst is used in the synthesis of biscoumarins and ortho -aminocarbonitriles. • Biscoumarins and ortho-aminocarbonitriles were obtained in good yields. • Catalyst reusability showed no significant loss in activity for four cycles. In the present work, a novel polymer supported Brønsted acidic ionic liquid catalyst is synthesized by functionalization of Merrifield resin with DABCO, 1,4-butane sultone and concentrated H 2 SO 4 is reported. The structure of synthesized catalyst was confirmed by FT-IR, SEM, EDX, XRD, XPS, TGA and DTA techniques. The catalytic efficiency of novel Brønsted acidic [MerDABCO-BSA][HSO 4 ] 2 was evaluated in the synthesis of biscoumarins from 4-hydroxycoumarin and aryl aldehydes in ethanol at 80 °C. Also, ortho -aminocarbonitriles were synthesized from cyclohexanone, malononitrile and aromatic aldehydes in ethanol:water (70:30 v/v) under ultrasonic condition. The catalyst exhibits good stability under thermal as well as ultrasonic conditions. The recycled catalyst demonstrated good catalytic efficiency for four cycles without significant deterioration in the catalytic activity. The present protocol offers advantages of operational simplicity, shorter reaction times and higher yields of the products. [ABSTRACT FROM AUTHOR]