نتایج جستجو برای: 1 8 dioxo octahydroxanthene
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Two new spiranoid withanolides, (20R,22R,23R)-12β ,17β ,22-trihydroxy-1-oxo-12,23-cycloergosta-2,24-dien-26,23-olide (3) and (23R)-5α ,6β ,12β ,21-tetrahydroxy-1,22-dioxo-12,23-cycloergosta-2,17,24-trien-26,23-olide (4) were isolated from plants of Jaborosa odonelliana and Jaborosa runcinata, respectively. Compounds 3 and 4 were characterized by a combination of spectroscopic methods (1D and 2D...
Four lanostane triterpenes, 3,7,11-trioxo-5α-lanosta-8,24(E)-dien-26-oic acid, methyl 11α-3,7-dioxo-5α-lanosta-8,24(E)-dien-26-oate, methyl 3,7,11,12,15,23-hexaoxo-5α-lanost-8-en-26-oate, and ethyl 3,7,11,12,15,23-hexaoxo-5α-lanost-8-en-26-oate, two sterols, (14α,22E)-14-hydroxyergosta-7,22-diene-3,6-dione and a steroid named as camphosterol A were isolated from a mixture of fruiting bodies and...
The reaction of dibenzoylacetylene with 4-alkylaminocoumarins in THF/H2O (50:50) lead to 4-(alkylamino)-3-(1,4-dioxo-1,4-diphenylbut-2-en-2-yl)-2H-chromen-2-one derivatives in good yields. When the reaction carried-out in DMSO the cyclized products 2-hydroxy-1-alkyl-3-(2-oxo-2-phenylethylidene)-2-phenyl-2,3-dihydrochromeno [4,3-b] pyrrol-4(1H)-ones were formed in good yields.
Isolation and structural elucidation of prune constituents were performed and total 10 compounds were determined by NMR and MS analyses. A novel compound was identified to be 2-(5-hydroxymethyl-2',5'-dioxo-2',3',4',5'-tetrahydro-1'H-1,3'-bipyrrole)carbaldehyde, and 7 phenolic compounds were isolated from prunes for the first time. In addition, antioxidant activity of them was evaluated on the b...
The high valent molybdenum-dioxo complex [MoO2Cl2] catalyzes the addition of dimethylphenylsilane to aldehydes and ketones to afford the corresponding dimethylphenylsilyl ethers in quantitative yield.
A novel thiol-reactive bifunctional agent, an analogue of fluorobenzaldehyde-O-[6-(2,5-dioxo-2,5dihydro-pyrrol-1-yl)-hexyl]oxime, (FBAM) has been synthesized. The new prosthetic group, [18F]FBAMPy, replaces the 4-fluorophenyl moiety with a 2-fluoropyridinyl moiety leading to increased polarity (FBAM analytical HPLC Rf = 6.4 min; FBAMPy Rf = 4.8 min) while retaining the sulfurreactive pendant. B...
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