One-Pot/Four-Step/Palladium-Catalyzed Synthesis of Indole Derivatives: The Combination of Heterogeneous and Homogeneous Systems

Synthesis of Indoles via Intermolecular and Intramolecular Cyclization by Using Palladium-Based Catalysts

As part of natural products or biologically active compounds, the synthesis of nitrogen-containing heterocycles is becoming incredibly valuable. Palladium is a transition metal that is widely utilized as a catalyst to facilitate carbon-carbon and carbon-heteroatom coupling; it is used in the synthesis of various heterocycles. This review includes the twelve years of successful indole synthesis using various palladium catalysts to establish carbon-carbon or carbon-nitrogen coupling, as well as the conditions that have been optimized.

Enantioselective synthesis of indole derivatives by Rh/Pd relay catalysis and their anti-inflammatory evaluation

An efficient Rh/Pd relay catalyzed intermolecular and cascade intramolecular hydroamination for the synthesis of exclusive trans 1-indolyl dihydronaphthalenols (up to 88% yield, 99% ee) is described under mild conditions. Moreover, the in silico and in vitro screening showed that the novel 1-indolyl dihydronaphthalenol products are potent lead compounds for treating inflammation disease.

Recent advances in the synthesis of indoles from alkynes and nitrogen sources

This review highlights ten years of success in the synthesis of indoles using alkynes and nitrogen sources as substrates.

A Reusable MOF-Supported Single-Site Zinc(II) Catalyst for Efficient Intramolecular Hydroamination of o-Alkynylanilines

The exploitation of new and active earth-abundant metal catalysts is critical for sustainable chemical production. Herein, we demonstrate the design of highly efficient, robust, and reusable Zn^II -bipyridine-based metal-organic framework (MOF) catalysts for the intramolecular hydroamination of o-alkynylanilines to indoles. Under similar conditions homogeneous catalytic systems mainly provide hydrolysate. Our results prove that MOFs support unique internal environments that can affect the direction of chemical reactions. The Zn^II -catalyzed hydroamination reaction can be conducted without additional ligands, base, or acid, and is thus a very clean reaction system with regard to its environmental impact.

Palladium-catalyzed primary amine-directed regioselective mono- and di-alkynylation of biaryl-2-amines

Palladium-catalyzed primary amine-directed controlled alkynylation of biaryl-2-amines has been developed by using haloalkynes as an alkynylating reagent.

Toward highly potent cancer agents by modulating the C-2 group of the arylthioindole class of tubulin polymerization inhibitors

New arylthioindole derivatives having different cyclic substituents at position 2 of the indole were synthesized as anticancer agents. Several compounds inhibited tubulin polymerization at submicromolar concentration and inhibited cell growth at low nanomolar concentrations. Compounds 18 and 57 were superior to the previously synthesized 5. Compound 18 was exceptionally potent as an inhibitor of cell growth: it showed IC₅₀ = 1.0 nM in MCF-7 cells, and it was uniformly active in the whole panel of cancer cells and superior to colchicine and combretastatin A-4. Compounds 18, 20, 55, and 57 were notably more potent than vinorelbine, vinblastine, and paclitaxel in the NCI/ADR-RES and Messa/Dx5 cell lines, which overexpress P-glycoprotein. Compounds 18 and 57 showed initial vascular disrupting effects in a tumor model of liver rhabdomyosarcomas at 15 mg/kg intravenous dosage. Derivative 18 showed water solubility and higher metabolic stability than 5 in human liver microsomes.

Facile Sc(OTf)3-catalyzed generation and successive aromatization of isobenzofuran from o-dicarbonylbenzenes

Isobenzofuran can be prepared from o-phthalaldehyde using hydrosilane. The formed isobenzofuran is trapped by an alkene via a Diels-Alder reaction. Further dehydration proceeds to furnish the conjugated aromatic compound. This multistep reaction was promoted by catalytic amounts of Sc(OTf)(3).

Ready synthesis of free N-H 2-arylindoles via the copper-catalyzed amination of 2-bromo-arylacetylenes with aqueous ammonia and sequential intramolecular cyclization

A wide range of free N-H 2-arylindoles were synthesised via the copper(II)-catalyzed amination of 2-bromo-arylacetylenes with aqueous ammonia and sequential intramolecular cyclization. The convenience and atom economy of aqueous ammonia, and the low cost of the copper catalytic system make this protocol readily superior in practical application.