99640-09-2Relevant academic research and scientific papers
Anti-inflammatory constituents of the Red Alga Gracilaria verrucosa and their synthetic analogues
Hung, The Dang,Hye, Ja Lee,Eun, Sook Yoo,Shinde, Pramod B.,Yoon, Mi Lee,Hong, Jongki,Dong, Kyoo Kim,Jung, Jee H.
, p. 232 - 240 (2008/12/22)
A chemical study on the anti-inflammatory components of the red alga Gracilaria verrucosa led to the isolation of new 11-deoxyprostaglandins (1-4), a ceramide (5), and a C16 keto fatty acid (6), along with known oxygenated fatty acids (7-14). Their structures were elucidated on the basis of NMR and MS data. The absolute configurations of compounds 1-5 were determined by Mosher's method. The anti-inflammatory activity of the isolated compounds (1-14) was evaluated by determining their inhibitory effects on the production of pro-inflammatory mediators (NO, IL-6, and TNF-α) in lipopolysaccharide (LPS)-activated RAW 264.7 murine macrophage cells. Compounds 9 and 10 exhibited the most potent activity. In the evaluation of these two compounds and derivatized analogues (15-40), the anti-inflammatory activity was enhanced in some synthetic analogues. These enone fatty acids were investigated as potential anti-inflammatory leads for the first time.
Allylic Mono- and Di-hydroxylation of Isolated Double Bonds with Selenium Dioxide-tert-Butyl Hydroperoxide. NMR Characterization of Long-chain Enols, Allylic and Saturated 1,4-Diols, and Enones
Knothe, Gerhard,Bagby, Marvin O.,Weisleder, David,Peterson, Robert E.
, p. 1661 - 1670 (2007/10/02)
Selenium dioxide with tert-butyl hydroperoxide as re-oxidant was used in the allylic hydroxylation of isolated double bonds in straight-chain hydrocarbons.This was shown for mono-unsaturated fatty acids, esters and alcohols.Either allylic position was hydroxylated individually or both positions reacted to give dihydroxy isomers, affording numerous novel hydroxy compounds.Yields of monohydroxy compounds in which the OH group is between the double bond and C-1 were usually higher than those in which the OH group is between the double bond and the methyl terminus.Monohydroxy products were used as starting material in subsequent allylic hydroxylation reactions to increase the yield of dihydroxy product, although this reaction is slow.Coinciding with the known mechanism, cis double bonds of starting materials isomerized nearly quantitatively to trans double bonds in the products while trans double bonds did not isomerize.Resonance differences of the olefinic carbons in 13C NMR of the unsaturated monohydroxy compounds show on which side of the double bond the hydroxy group is located.The magnitude of these differences depends on the nature of the group at C-1 and the distance of the double bond from C-1.Corresponding saturated hydroxy fatty acids were synthesized with the hydrazine-air system. 13C-NMR of the saturated compounds showed that the dihydroxy products were erythro/threo diastereoisomers.With this assignment, 1H NMR of the unsaturated allylic dihydroxy compounds may be used to distinguish these diastereoisomers.The olefinic protons of the erythro dihydroxy diastereoisomer resonate downfield from those of the threo form.The threo diastereoisomers are formed in higher yields than theirerythro counterparts.Compounds with allylic keto group (enones) analogous to the monohydroxy products arose as side products.The 13C NMR spectra of these enones are discussed.
Allylic Hydroperoxide Rearrangement: β-Scission or Concerted Pathway?
Porter, Ned A.,Wujek, Jacqueline Sullivan
, p. 5085 - 5089 (2007/10/02)
The rearrangements of the allylic hydroperoxides derived from oleic acid have been studied.Two hydroperoxides are formed by singlet-oxygen oxidation of oleic acid trans-9-hydroperoxyoctadec-10-enoic acid (5) and trans-10-hydroperoxyoctadec-8-enoic acid (6).These hydroperoxides can be separated by reverse-phase chromatography.Rearrangement of 18O-labeled hydroperoxides (5 or 6) under a 32O2 atmosphere led to no incorporation of 16O into the rearrangement products.Similarly, rearrangement of 16O-labeled hydroperoxides (5 or 6) under a 36O2 atmosphere led to no incorporation of 18O into the rearrangement products.The hydroperoxide 5 rearranges to a mixture of 5 and trans-11-hydroperoxyoctadec-9-enoic acid and alcohols and ketones resulting from Russell termination steps.The results are discussed in terms of a concerted rearrangement of allylic peroxyl radicals proceeding through a five-membered-ring transition state.
