Synthesis of carbazoloquinone derivatives and their antileukemic activity via modulating cellular reactive oxygen species

Access to 5-Methyl-5H-naphtho[2,3-c]carbazole-8,13-dione Derivatives via Copper-Catalyzed Intramolecular Isomerization

Carbazole-fused quinones are important compounds for their potential pharmacological activities and photophysical properties. Here, a novel copper-catalyzed intramolecular isomerization process to access a new class of naphtho[2,3-c]carbazole-8,13-dione derivatives via a furan isomerization/γ-H elimination and β-C elimination/6π-electrocyclization/aromatization cascade is reported. Furthermore, the preliminary photophysical properties of the functional 5-methyl-5H-naphtho[2,3-c]carbazole-8,13-dione derivatives have been studied.

Alashanines A-C, Three Quinone-Terpenoid Alkaloids from Syringa pinnatifolia with Cytotoxic Potential by Activation of ERK

Three quinone-terpenoid alkaloids, alashanines A-C (1-3), possessing an unprecedented 6/6/6 tricyclic conjugated backbone and quinone-quinoline-fused characteristic, were isolated from the peeled stems of Syringa pinnatifolia. Their structures were elucidated by analysis of extensive spectroscopic data and quantum chemical calculations. A hypothesis of biosynthesis pathways for 1-3 was proposed on the basis of the potential precursor iridoid and benzoquinone. Compound 1 exhibited antibacterial activities against Bacillus subtilis and cytotoxicity against HepG2 and MCF-7 human cancer cell lines. The results of the cytotoxic mechanism revealed that compound 1 induced apoptosis of HepG2 cells through activation of ERK.

Comparative analysis of p-terphenylquinone and seriniquinone derivatives as reactive oxygen species-modulating agents

Quinones are widespread in plants, animals, insects, and microorganisms. Several anticancer agents contain quinone structures as critical parts to show remarkable potential and distinctive modes of actions. The purpose of this study was to investigate the structure-activity relationships of microbial quinones and their derivatives as anticancer agents. A series of p-terphenylquinone and seriniquinone derivatives were therefore prepared. Treatment of the synthesized quinones possessed antiproliferative activity on human leukemia HL-60 cells in a dose-dependent fashion. In addition, seriniquinone derivatives elevated cellular reactive oxygen species (ROS) levels, thereby triggering the ensuing apoptotic events. Our findings emphasize the excellent potential of seriniquinone derivatives as redox cycling-induced ROS-modulating anticancer agents.

A Chemo- and Regioselective Tandem [3 + 2]Heteroannulation Strategy for Carbazole Synthesis: Combining Two Mechanistically Distinct Bond-Forming Processes

A modular approach to prepare tri- and tetracyclic carbazoles by a sequential [3 + 2]heteroannulation is described. First, optimization of Pd-catalyzed Buchwald–Hartwig amination followed by C/N-arylation in a one-pot process is established. Second, mechanistic analyses identified the origins of chemo- and regioselective sequential control of both bond-forming steps. Finally, the substrate scope is demonstrated by the preparation of a range of tri- and tetracyclic carbazoles, including expedient access to several natural products and anti-cancer agents.

The Synthesis and Chemistry of Quinolinediones and their Carbocyclic Analogs

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Quinoline-5,8-dione and naphthoquinone nuclei are very important substructures in industrial chemicals and pharmaceuticals. These compounds exhibit a wide variety of activities, including activity as antifungal, antibacterial, antimalarial, antineoplastic, anticoagulant, anticancer, antiviral, radical scavenging, antiplatelet, trypanocidal, cytotoxic and antineoplastic agents. Currently, several research articles about the importance of many natural and synthetic drugs containing quinolinequinone have been reported. This review covers the progress in quinolinequinone and naphthoquinone chemistry over the last five decades.

Synthesis of [1,2,4]triazolo[4,3-a]quinoxaline-1,3,4-oxadiazole derivatives as potent antiproliferative agents via a hybrid pharmacophore approach

Imiquimod (1-isobutyl-1H-imidazo[4,5-c]quinolin-4-amine) is efficacious in topical therapy for certain types of skin cancers. Structurally similar EAPB0203 (N-methyl-1-(2-phenethyl)imidazo[1,2-a]quinoxalin-4-amine) has been shown higher in vitro potency than imiquimod. Besides, triazole, oxadiazole, and thiadiazole rings are privileged building blocks in drug design. A series of [1,2,4]triazolo[4,3-a]quinoxaline-1,3,4-oxadiazole and [1,2,4]triazolo[4,3-a]quinoxaline-1,3,4-thiadiazole derivatives were therefore synthesized by incorporation of these rings into the structure of EAPB0203 and assessed their antiproliferative effects against various cancer cell lines. The 1,3,4-oxadiazole derivatives demonstrated the superior effectiveness compared to imiquimod and EAPB0203. Our findings highlight the excellent potential of [1,2,4]triazolo[4,3-a]quinoxaline-1,3,4-oxadiazole derivatives as anticancer agents.

Ruthenium(II)-Catalyzed Double Annulation of Quinones: Step-Economical Access to Valuable Bioactive Compounds

Double ruthenium(II)-catalyzed alkyne annulations of quinones were accomplished. Thus, a strategy is reported that provides step-economical access to valuable quinones with a wide range of applications. C-H/N-H activations for alkyne annulations of naphthoquinones provided challenging polycyclic quinoidal compounds by forming four new bonds in one step. The singular power of the thus-obtained compounds was reflected by their antileukemic activity.