A novel CAN-SiO2-mediated one-pot oxidation of 1-keto-1,2,3,4-tetrahydrocarbazoles to carbazoloquinones: Efficient syntheses of murrayaquinone A and koeniginequinone A

Direct oxidation of bromo-derived Fischer-Borsche oxo-ring using molecular iodine with combined experimental and computational study

A direct oxidation of the bromo-derived Fischer-Borsche oxo-ring leading to carbazolequinone has been developed by using molecular iodine. This unprecedented transformation has been used for the modular synthesis of the anti-cardiotonic agent murrayaquinone. Furthermore, the present method has been generalized to a broad range of functional groups, with good to excellent yield.

[Development of New Synthetic Methods for Carbazole Compounds Aimed at Drug Discovery and Exploratory Research on Pharmaceutical Materials]

We are developing the synthesis of biologically interesting carbazole compounds, including natural products by tandem cyclic reactions. In this report, we describe the new synthesis of carbazole-1,4-quinones as follows; 1) the synthesis of carbazole-1,4-quinones using a tandem ring closing metathesis (RCM) -dehydrogenation reaction, 2) a novel one-pot synthesis of carbazole-1,4-quinone by consecutive Pd-catalyzed cyclocarbonylation, desilylation, and oxidation reactions. Two new synthetic strategies were applied to the synthesis of carbazole-1,4-quinone alkaloids and ellipticine quinones, and then the antiproliferative activity against HCT-116 and HL-60 cells of the synthesized compounds were evaluated.

Synthesis of carbazoloquinone natural products ‘on-water’

The total synthesis of a number of carbazolo-1,4-quinone natural products using on-water chemistry is described.

Antibacterial Activity of Murrayaquinone A and 6-Methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione

The antibacterial activity of Murrayaquinone A (10), a naturally occurring carbazoloquinone alkaloid, and 6-methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione (11), a synthetic carbazoloquinone, both obtained during the development of the synthesis of Carbazomycin G, having unique quinone moiety, was studied against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas sp.) bacteria. Compound 10 showed antibacterial activities against both of Escherichia coli and Staphylococcus aureus whereas compound 11 indicated the activity against Staphylococcus aureus only. Both compounds 10 and 11 exhibited minimum inhibitory concentration (MIC) of 50 μg mL⁻¹ against Staphylococcus aureus.