A new process of multicomponent Povarov reaction–aerobic dehydrogenation: synthesis of polysubstituted quinolines

The Povarov Reaction: A Versatile Method to Synthesize Tetrahydroquinolines, Quinolines and Julolidines

The multicomponent Povarov reaction represents a powerful approach for the construction of substances containing N-heterocyclic frameworks. By using the Povarov reaction, in addition to accessing tetrahydroquinolines, quinolines and julolidines in a single step, it is possible to form the following new bonds: two Csp 3–Csp 3 and one Csp 3–Nsp 3, two Csp 2–Csp 2 and one Csp 2–Nsp 2, and four Csp 3–Csp 3 and two Csp 3–Nsp 1, respectively. This short review discusses the main features of the Povarov reaction, including its mechanism, the reaction scope by employing different catalysts and substrates, as well as stereoselective versions.

1 Introduction

2 Mechanism of the Povarov Reaction

3 Tetrahydroquinolines

4 Quinolines

5 Julolidines

6 Concluding Remarks

From Conventional Lewis Acids to Heterogeneous Montmorillonite K10: Eco-Friendly Plant-Based Catalysts Used as Green Lewis Acids

The concept of green chemistry began in the USA in the 1990s. Since the publication of the 12 principles of this concept, many reactions in organic chemistry have been developed, and chemical products have been synthesized under environmentally friendly conditions. Lewis acid mediated synthetic transformations are by far the most numerous and best studied. However, the use of certain Lewis acids may cause risks to environmental and human health. This Review discusses the evolution of Lewis acid catalyzed reactions from a homogeneous liquid phase to the solid phase to yield the expected organic molecules under green, safe conditions. In particular, recent developments and applications of biosourced catalysts from plants are highlighted.

Synthesis and Reactivity of Propargylamines in Organic Chemistry

Propargylamines are a versatile class of compounds which find broad application in many fields of chemistry. This review aims to describe the different strategies developed so far for the synthesis of propargylamines and their derivatives as well as to highlight their reactivity and use as building blocks in the synthesis of chemically relevant organic compounds. In the first part of the review, the different synthetic approaches to synthesize propargylamines, such as A³ couplings and C-H functionalization of alkynes, have been described and organized on the basis of the catalysts employed in the syntheses. Both racemic and enantioselective approaches have been reported. In the second part, an overview of the transformations of propargylamines into heterocyclic compounds such as pyrroles, pyridines, thiazoles, and oxazoles, as well as other relevant organic derivatives, is presented.

An Efficient One-Pot Synthesis of Densely Functionalized Fused-Quinolines via Sequential Ugi4CC and Acid-Mediated Povarov-Type Reaction

A divergent synthesis of fused-quinolines has been explored by performing Ugi four-component condensation and sulfuric acid promoted deprotection/Povarov-type reaction in one-pot. The process involves Ugi condensation of propiolic acids, aldehydes/ketones, aminoaldehyde acetals and isocyanides followed by sulfuric acid promoted deprotection and Povarov-type reaction with anilines in ethanol. This method enables straightforward access to the structurally diverse 2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-ones (DHPQ), 3,4-dihydrobenzo[b][1,6]naphthyridin-1(2H)-ones (DHBN), and 2,3,4,5-tetrahydro-1H-azepino[4,3-b]quinolin-1-ones (THAQ), starting from readily available starting materials.

Novel routes to quinoline derivatives from N-propargylamines

A walk around the new avenue to the synthesis of quinoline derivatives from N-propargylamines.

Synthesis, and the antioxidant, neuroprotective and P-glycoprotein induction activity of 4-arylquinoline-2-carboxylates

An efficient synthesis of 4-arylquinoline-2-carboxylates and their antioxidant, neuroprotective and P-glycoprotein induction activity have been described.

N-fused imidazoles as novel anticancer agents that inhibit catalytic activity of topoisomerase IIα and induce apoptosis in G1/S phase

On the basis of structures of known topoisomerase II catalytic inhibitors and initial molecular docking studies, bicyclic N-fused aminoimidazoles were predicted as potential topoisomerase II inhibitors. They were synthesized by multicomponent reactions and evaluated against human topoisomerase IIα (hTopoIIα) in decatenation, relaxation, cleavage complex, and DNA intercalation in vitro assays. Among 31 compounds of eight different bicyclic scaffolds, it was found that imidazopyridine, imidazopyrazole, and imidazopyrazine with suitable substituents exhibited potent inhibition of catalytic activity of hTopoIIα while not showing DNA intercalation. Molecular docking studies and molecular dynamics (MD) simulation analysis, ATPase-kinetics and ATP-dependent plasmid relaxation assay revealed the catalytic mode of inhibition of the title compounds plausibly by blocking the ATP-binding site. N-Fused aminoimidazoles showed potent anticancer activities in kidney and breast cancer cell lines, low toxicity to normal cells, relatively higher potency compared to etoposide and 5-fluorouracil in kidney cancer cell lines, and potent inhibition in cell migration. These compounds were found to exert apoptotic effect in G1/S phase.

Unsaturated lactams: new inputs for povarov-type multicomponent reactions

Unsaturated lactams with endo- or exocyclic C-C double bonds constitute a set of reactive inputs that serve as the electron-rich olefin component in Povarov reactions. These substrates afford the multicomponent adducts in convenient yields and offer a wide range of structural diversity. Postcondensation transformations allow direct access to a variety of lactam-fused and amide-substituted quinoline derivatives.