An Efficient One-Pot Synthesis of Benzo[4,5]imidazo[1,2-a]quinoxalines via Copper-Catalyzed Process

Recent Advances in the Tandem Copper-Catalyzed Ullmann-Goldberg N-Arylation–Cyclization Strategies

N‒Aryl bond formation under copper catalysis has been playing a pivotal role and has been extensively used as a key step in the total syntheses of several therapeutic molecules. The...

Facile synthesis of C6-substituted benz[4,5]imidazo[1,2-a]quinoxaline derivatives and their anticancer evaluation

Cancer remains a leading cause of death worldwide, resulting in continuous efforts to discover and develop highly efficacious anticancer drugs. High-throughput screening of heterocyclic compound libraries is one of the promising approaches that provided several new lead molecules with a novel mechanism of action. On the basis of the promising anticancer potential of imidazoquinoxaline as well as the structurally similar imidazoquinoline-derived scaffold, we prepared a set of C6-substituted benzimidazo[1,2-a]quinoxaline derivatives via two novel synthetic routes using commercially available starting materials, with good to excellent yields and evaluated their anticancer activity against the NCI-60 cancer cell lines. The one-dose (10 µM) anticancer screening of the synthesized compounds in the NCI-60 cell line panel revealed that the substituents have a significant role in the activity. In particular, the indole (7f), imidazole (7g), and benzimidazole (7h) derivatives showed significant activity against the triple-negative breast cancer cell line, MDA-MB-468. The lead compounds also exhibited notable IC₅₀ values against another breast cancer cell line, MCF-7. Furthermore, it was observed that these compounds were relatively nontoxic to normal cell lines: HEK293 (human embryonic kidney cell line) and MCF12A (nontumorigenic human breast epithelial cell line). The IC₅₀ values against healthy cells were at least 5- to 11-fold higher, offering a new class of heterocycles that can be further developed as promising therapeutics for cancer treatment.

Synthesis of benzo[4,5]imidazo[1,2-a]quinoxalines by I2-mediated sp3 C–H amination

Benzo[4,5]imidazo[1,2-a]quinoxalines were synthesized by I₂-mediated sp³ C–H amination under transition-metal free conditions in an efficient and scalable fashion.

Design and Synthesis of a Novel Banana-Shaped Functional Molecule via Double Cross-Coupling

A novel banana-shaped molecule using 2,8-Dimethyl-6H,12H-5,11-methanodibenzo [b,f] [1,5]diazocine (Tröger's base) as bent-core was synthesized via double Carbon-Carbon cross-coupling reaction. The double Sonogashira cross-coupling reaction was optimized by using Pd(PPh₃)₂Cl₂ as catalyst, CuI as cocatalyst and diisopropylamine as base in place of triethylamine. The structure of this compound was confirmed by ¹H-NMR, ¹³C-NMR, Fourier transform infrared (FT-IR) spectroscopy and mass spectrometry.

One-Pot Synthesis of Indole-3-acetic Acid Derivatives through the Cascade Tsuji-Trost Reaction and Heck Coupling

A practical palladium-mediated cascade Tsuji-Trost reaction/Heck coupling of N-Ts o-bromoanilines with 4-acetoxy-2-butenonic acid derivatives using a Pd(OAc)₂/P( o-tol)₃/DIPEA system is described for a straightforward synthesis of indole-3-acetic acid derivatives. This methodology was successfully applied to synthesize various substituted indole/azaindole-3-acetic acid derivatives and Almotriptan, which is a drug for the acute treatment of migraines. Moreover, a plausible cyclization mechanism has been proposed.

One-pot strategy of copper-catalyzed synthesis of 1,2-disubstituted benzimidazoles

A simple, one-pot and copper-catalyzed coupling reaction for the construction of 1,2-disubstituted benzimidazole derivatives is described. A low-cost copper salt and a weak base, K₃PO₄, were utilized in this reaction. A variety of 1,2-disubstituted benzimidazoles were obtained in moderate to excellent yields.

Green synthesis of 1,4-benzodiazepines over La2O3 and La(OH)3 catalysts: possibility of Langmuir–Hinshelwood adsorption

Adsorption of all the reactants and order of addition play a key role in the synthesis of 1,4-diazepines depicting possibility of Langmuir–Hinshelwood mechanism.

One-pot three-component synthesis of quinazolines via a copper-catalysed oxidative amination reaction

A copper-catalysed three-component reaction for constructing a series of quinazoline derivatives has been developed.

A novel type of AIE material as a highly selective fluorescent sensor for the detection of cysteine and glutathione

Novel kind of AIE materials were easily obtained in moderate yields via tandem reactions. New highly selective cysteine detection system was also developed based on this AIE compound.

Quinoxaline: a new directing group for ortho C–H alkenylation / intramolecular ortho C–H cycloamination under open air leading to bioactive polynuclear N-heteroarenes

A two-step strategy involving quinoxaline directed the ortho C–H alkenylation/intramolecular ortho C–H cycloamination afforded new PDE4 inhibitors.

I2-catalyzed one-pot synthesis of pyrrolo[1,2-a]quinoxaline and imidazo[1,5-a]quinoxaline derivatives via sp3and sp2C–H cross-dehydrogenative coupling

An efficient I₂-catalyzed cascade coupling protocol was developed for the synthesis of pyrrolo[1,2-a]quinoxaline and imidazo[1,5-a]quinoxaline derivativesviasp³and sp²C–H cross-dehydrogenative coupling.

One-pot synthesis of benzo[4,5]imidazo[1,2-a]quinazoline derivatives via facile transition-metal-free tandem process

A one-pot transition metal-free method for synthesizing benzo[4,5]imidazo[1,2-a]quinazoline and imidazo[1,2-a]quinazoline derivatives has been developed. The approach is widely applicable to 2-fluoro-, 2-chloro-, 2-bromo- and 2-nitro-substituted aryl aldehyde and ketone substrates. The fluorescence properties of target compounds were studied.