Building libraries of skeletally diverse scaffolds from novel heterocyclic active methylene compound through multi-component reactions

Ultrasound-Facilitated Direct meta-C-H Functionalization of Arenes: A Time-Economical Strategy under Ambient Temperature with Improved Yield and Selectivity

The horizon of ultrasound-assistance has been expanded to palladium-catalyzed distal C-H functionalization of arenes. Compared to thermal conditions, operationally simple ultrasound mediated distal C-H functionalization occurred with a shorter reaction time and enhanced reactivity of reactants to give superior yields with improved selectivity both in terms of meta:others and mono:di. A wide variety of meta-functionalizations such as olefination, alkylation, acetoxylation, allylation and cyanation were successfully carried out under ambient temperature.

Diversity oriented multi-component reaction (DOS-MCR) approach to access natural product analogues: regio- and chemo-selective synthesis of polyheterocyclic scaffolds via one-pot cascade reactions

Skeletally diverse and complex aza-cyclopenta(cd)diindene, pyrrolo(3,4-d)pyridine-13-carboxamide, and furo-pyrrolo(1,2-a)imidazole-4-carboxamide fused polyheterocyclic hybrid scaffolds and a furo(2,3-b)furan core have been accessed via one-pot three-component reaction by exploiting the build/couple/pair strategy of diversity oriented synthesis (DOS). This protocol is metal free, has a good substrate scope and affords products with good to excellent yields and regio- and chemo-selectivity. The heterocyclic skeletons obtained in this study mimic natural products such as eupolauramine, gracilamine and presilphiperfolanol.

Water mediated synthesis of 6-amino-5-cyano-2-oxo-N-(pyridin-2-yl)-4-(p-tolyl)-2H-[1,2'-bipyridine]-3-carboxamide and 6-amino-5-cyano-4-(4-fluorophenyl)-2-oxo-N-(pyridin-2-yl)-2H-[1,2'-bipyridine]-3-carboxamide - An experimental and computational studies with non-linear optical (NLO) and molecular docking analyses

6-Amino-5-cyano-2-oxo-N-(pyridin-2-yl)-4-(p-tolyl)-2H-[1,2'-bipyridine]-3-carboxamide and 6-amino-5-cyano-4-(4-fluorophenyl)-2-oxo-N-(pyridin-2-yl)-2H-[1,2'-bipyridine]-3-carboxamide were synthesized through three-component reaction between N¹,N³-di(pyridin-2-yl)-malonamide, aldehyde and malononitrile in water using triethylamine as a base at room temperature. Synthesized compounds were characterized by using different techniques (FT-IR, NMR and X-ray diffraction). Additionally, the mentioned compounds were investigated by computational chemistry methods. Obtained results were supported with calculated results. Additionally, NLO properties and molecular docking analyses of related compounds were examined in detail. The binding modes of the compounds 4a and 4b were explored with the colchicine binding site of tubulin, from molecular docking studies, remarkable interactions have been observed for 4a and 4b near to the colchicines binding site of tubulin that may contribute to the inhibition of tubulin polymerization and anticancer activity.

Synthesis and pharmacological properties of polysubstituted 2-amino-4H-pyran-3-carbonitrile derivatives

2-Amino-3-cyano-4H-chromenes are structural core motifs that received increasing attention in the last years due to their interesting potential pharmacological properties. In this review, the synthetic methods for these compounds are classified based on the type of catalyst in the pertinent reactions. In addition, the wide range of pharmacological properties of these compounds is covered in a separate section.

Design and synthesis of benzothiazole/thiophene-4H-chromene hybrids

A library of 4H-chromene derivatives with heterocyclic substituent's at the 3 and 4-positions was synthesized in a convenient DBU catalysed three component synthesis between salicylaldehyde, acetonitrile derivatives and thiazolidinedione to afford 2-amino-3-benzothiazole-4-heterocycle-4H-chromenes and 2-amino-3-thiophenoyl-4-heterocycle-4H-chromenes derivatives in ethanol and a mixture of ethanol and water (1 : 1) at room temperature. The significance of this protocol is the feasibility of incorporating substituents simultaneously at the 3 and 4 positions of 4H-chromenes in an efficient three component reaction.

Facile Construction of Novel Fused Chromeno[2,3-d]Thiazolo[3,2-a]Pyrimidine Derivatives in Biocompatible Ionic Liquid under Solvent-Free Conditions

A simple and efficient three-component reaction is reported between 2,3-dihydro-7-hydroxythiazolo[3,2-a]pyrimidin-5-one, dimedone and aromatic aldehydes for synthesis of biologically important novel heterocycles containing thiazolo[3,2-a]pyrimidine and chromene as biologically active moieties. The SO3H-functionalised halogen-free ionic liquid [MIM(CH2)4SO3H][HSO4-] is found to be an environmentally benign catalyst for this reaction without using any solvent. This SO3H-functionalised ionic liquid could be recovered and used at least four times without considerable reduction in activity. Good functional group tolerance, broad scope of usable substrates and good to excellent yields of products are the other prominent features of the present synthetic protocol.