Synthesis of (+)2,3-PinDione, a versatile chiral 1,2-diketone

New manganese-scaffolded organic triple-deckers based on quinoxaline, pyrazine and pyrimidine cores

“…At a scan rate of 200 mV s −1 compounds 2b-c displayed a series of three-to-four close reduction waves at potentials slightly higher than for 2,5-diphenylpyrazine (−1.85 V vs. SCE in CH 3 CN) with reverse oxidation waves symptomatic of a possible fast chemical degradation of the reduced species through a ECE scheme. Interestingly another pyrazine-based triple-decker terpenic derivative 8 16 displayed two relatively distant reversible reduction waves, the first one occurring at a potential more positive by 0.8 V than that measured for the metal-free parent pyrazine ligand 7 (−2.24 V, DE c/a = 186 mV, scan rate 800 mV s −1 , MeCN). A comparison of the reduction potentials of 1b 11 and 6b, although measured in different conditions, gives a good illustration of how the extension of the p-aromatic system at the central heterocycle lowers the energy of the LUMOs, which are populated upon reduction.…”

Synthesis and study of the antimalarial cardamom peroxide

“…54,55 If our hypothesis is correct, this pathway should also produce peroxy ester 28 as a byproduct, a compound we have not isolated to date. We have, however, observed small amounts (~5%) of dione 30 56 in reactions utilizing the Co(acac) 2 /PhSiH 3 system, conditions which also produce nopinone (Table 2, entry 4). It is plausible this compound comes from reduction of 28 with concomitant loss of acetic acid, a process likely driven by relief of steric strain with the gem -dimethyl group of the pinane ring system.…”

Copper Complex of Pinene based Schiff base [CuSBADBH]2: Synthesis and its Application in Catalytic Asymmetric Nitroaldol (Henry) Reaction

“…Ozonolysis of 13 in dichloromethane and methanol at À78 8C produced ozonide, which was cleaved by dimethyl sulfide to render diketone 16 in 95 % yield. [17] The diketone 16 was then reacted with hydroxylamine hydrochloride and sodium acetate in ethanol to afford a mixture of compounds that contain desired 2-keto-3-oxime 15, regioisomer, (2E)-3-keto-2-oxime, 17 and little dioxime 18. The crude NMR spectra of keto-oxime mixture showed that the ratio of 15:17 is 57:43.…”