1212331-85-5Relevant academic research and scientific papers
An Easy Route to Enantiomerically Enriched 7- and 8-Hydroxy-stearic Acids by Olefin-Metathesis-Based Approach
Boga, Carla,Drioli, Sara,Forzato, Cristina,Micheletti, Gabriele,Nitti, Patrizia,Prati, Fabio
, p. 1354 - 1358 (2016)
The synthesis of enantiomerically enriched 7- and 8-hydroxy-stearic acids (7- and 8-HSA) has been successfully accomplished starting from chiral nonracemic 1-pentadecen-4-ol and 1-tetradecen-4-ol, respectively. Their Yamaguchi's esterification with 4-pentenoic and 5-hexenoic acids, respectively, afforded the suitable dienic esters which were submitted to ring-closing metathesis reaction. After hydrogenation and basic hydrolysis of the complex reaction mixture, chiral nonracemic 7- and 8-HSA were obtained in about 40% total yield.
Enzymatic kinetic resolution of hydroxystearic acids: A combined experimental and molecular modelling investigation
Ebert, Cynthia,Felluga, Fulvia,Forzato, Cristina,Foscato, Marco,Gardossi, Lucia,Nitti, Patrizia,Pitacco, Giuliana,Boga, Carla,Caruana, Paolo,Micheletti, Gabriele,Calonghi, Natalia,Masotti, Lanfranco
, p. 38 - 45 (2012/11/07)
Enantioenriched 7-, 8-, 9-, and 10-hydroxystearic acids (HSA) were obtained, for the first time, by kinetic resolution of their racemates with lipases CALB and PS, in the presence of vinyl acetate. Among them, the best results were obtained for 7-HSA and 9-HSA, whose enantiomeric excess was around 55%. The same resolutions carried out on the hydroxy esters completely failed. For the acid substrates neither the Kazlauskas' rule nor the 3D-QSAR model could be applied, since both models are focused on the CALB alcohol-pocket evaluation and not on the acyl-pocket one. Therefore, a semiquantitative approach was used, whose results were in accordance with our findings, as far as the absolute configuration of the product is concerned.
Influence of positional isomers on the macroscale and nanoscale architectures of aggregates of racemic hydroxyoctadecanoic acids in their molecular gel, dispersion, and solid states
Abraham, Shibu,Lan, Yaqi,Lam, Ricky S. H.,Grahame, Douglas A. S.,Kim, Jennifer Jae Hee,Weiss, Richard G.,Rogers, Michael A.
, p. 4955 - 4964 (2012/07/13)
Inter/intramolecular hydrogen bonding of a series of hydroxystearic acids (HSAs) are investigated. Self-assembly of molecular gels obtained from these fatty acids with isomeric hydroxyl groups is influenced by the position of the secondary hydroxyl group. 2-Hydroxystearic acid (2HSA) does not form a molecular dimer, as indicated by FT-IR, and growth along the secondary axis is inhibited because the secondary hydroxyl group is unable to form intermolecular H-bonds. As well, the XRD long spacing is shorter than the dimer length of hydroxystearic acid. 3-Hydroxystearic acid (3HSA) forms an acyclic dimer, and the hydroxyl groups are unable to hydrogen bond, preventing the crystal structure from growing along the secondary axis. Finally, isomers 6HSA, 8HSA, 10HSA, 12HSA, and 14HSA have similar XRD and FT-IR patterns, suggesting that these molecules all self-assemble in a similar fashion. The monomers form a carboxylic cyclic dimer, and the secondary hydroxyl group promotes growth along the secondary axis.
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.
Stereospecific Removal of the pro-R Hydrogen at C-8 of (9S)-Hydroperoxyoctadecadienoic Acid in the Biosynthesis of Colneleic Acid
Fahlstadius, Per,Hamberg, Mats
, p. 2027 - 2030 (2007/10/02)
The stereochemistry of hydrogen removal in the conversion of (9S)-hydroperoxyoctadeca-(10E,12Z)-dienoic acid (2) into colneleic acid (4) was studied. -(2) and -(2) were incubated with the 105 000g particle fraction of potato homogenate and the colneleic acid formed was isolated.Mass spectrometric analysis demonstrated that colneleic acid which was biosynthesized from the -hydroperoxide was largely devoid of deuterium, whereas colneleic acid produced from the -hydroperoxide retained most of the deuterium.Accordingly, there is a selective removal of the pro-R hydrogen at C-8 in the biosynthesis of colneleic acid from (9S)-hydroperoxyoctadeca-(10E,12Z)-dienoic acid.
