Occurrence, Biogenesis, and Synthesis of Biologically Active Carbazole Alkaloids

Total Synthesis of (&plusmn;)-Carquinostatin A, and Asymmetric Total Synthesis of (<i>R</i>)-(−)-Carquinostatin A and (<i>S</i>)-(+)-Carquinostatin A

“…Removal of the solvent under reduced pressure gave the residue, which was acetylated in CH 2 Cl 2 (5 mL) in the presence of Ac 2 O (95 µL, 1.0 mmol), Et 3 N (278 µL, 2.0 mmol) and 4-N,Ndimethylaminopyridine (DMAP) (catalytic amount) under Chart 4 stirring for 12 h in N 2 atmosphere. The mixture was quenched with aqueous NH 4 Cl solution, and the mixture was extracted with CH 2 Cl 2 . The CH 2 Cl 2 layer was washed with water and brine, and dried over Na 2 SO 4 .…”

“…A solution of (−)-acetate 18a (180 mg, 0.50 mmol) and Ac 2 O (142 µL, 1.50 mmol) in the presence of Et 3 N (418 µL, 3.00 mmol) in CH 2 Cl 2 (10 mL) under Ar atmosphere was stirred at an ambient temperature for 12 h. The mixture was quenched with aqueous NH 4 Cl solution, and then the mixture was extracted with EtOAc. The EtOAc layer was washed with water and brine, dried over Na 2 SO 4 .…”

“…Using the Mosher method, 1) the absolute stereochemistry at the C-11 position of carquinostatin A (1a) was determined to be R. Synthetic studies of the carbazole alkaloid were developed by the Knölker group. [4][5][6][7][8][9] The first total synthesis of (±)-carquinostatin A (1a) was completed by the Knölker group using two iron-and nickel-mediated coupling reactions, and palladium-mediated oxidative cyclization. [10][11][12] The first enantioselective total synthesis of (R)-(−)-carquinostatin A (1a) was then accomplished through the construction of a carbazole framework based on iron-and nickel-mediated coupling reactions.…”

In Vitro Activity of Synthesized 6-Chloro-2-methyl-1H-carbazole- 1, 4(9H)-dione against Methicillin-Resistant Staphylococcus aureus

“…Inhibitory activity of Carbazomycin B [2] and Carbazomycin C [3] against 5-lipoxygenase were also observed (19). Carbazomycin G [7], having unique quinol moiety, shows antifungal activity against Trichophyton species (14). Recently we have reported that 3-methyl-1H-carbazole-1,4(9H)-dione and 6-methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione both having unique quinone moiety, exhibited antibacterial activity (20).…”

Total Synthesis of Carbazomycins A and B

“…[1][2][3][4][5][6] Among them, carbazomycins have a simple structure, but attractive biological activities. Especially, carbazomycins A and B, which were isolated from the extract of cultured mycelia of Streptoverticillium ehimensis strain H1051-MY10 [7][8][9] (Chart 1), show inhibitory activity against 5-lipoxygenase, and have weak antibacterial and antiyeast activities.…”