Formation of the ortho-quinone mansonone C from 7-hydroxycadalene on silica gel

Acceleration Effect of Bowl‐Shaped Structure in Aerobic Oxidation Reaction: Synthesis of Homosumaneneortho‐Quinone and Azaacene‐Fused Homosumanenes

“…reported that 7‐hydroxycadalene was oxidized on silica gel to afford ortho ‐quinone mansonone under irradiation of white fluorescent light, and the photochemical oxidation reaction required 5∼6 days to complete (Figure 1b). [13] Meanwhile, we realized that the oxidation finished within 1 h in the case of 2 having a curved‐π skeleton. Herein, we report the acceleration effect in the aerobic oxidation that originates from the strained bowl‐shaped structure (Figure 1d).…”

“…After concentration, the filtrate was charged on a PTLC plate, and the PTLC plate was irradiated with UV light (λ = 254 nm) for 1 h (Figure S2). Then, the PTLC plate was soaked in CHCl 3 to separate, affording 3 (20.5 mg, 66.9 μmol, 62.0 %) as an orange solid and 4 (5.7 mg, 10 μmol, 9.0 %) as a white solid; 3: R f = 0.15 (CHCl 3 ); Melting point: 327 °C (dec.); 1 H NMR (CDCl 3 , 400 MHz) δ (ppm) 8.03 (d, J = 7.8 Hz, 2H), 7.65 (d, J = 7.8 Hz, 2H), 7.56 (s, 2H), 4.32 (s, 4H); 13…”

The role of free radicals in the decomposition of the phytoalexin desoxyhemigossypol

“…~~-~~ A free radical oxidation has been implicated in the decomposition of the elm tree metabolite 7-hydroxycadalene in air on silica gel plates. 24 Oxygen-free radicals apparently also are involved in the spermicidal activity of the HG dimer, gossypol, which is being widely studied as a male antifertility agent. For example, in the presence but not in the absence of SOD or catalase, gossypoltreated sperm was found to fertilize sea urchin eggs n~rmally.~' Gossypol promoted both the formation of 02'in rat liver microsomes and a radical species that was partially quenched by SOD, but was more effectively quenched by catalase in human sperm cell suspensions.…”