- Asymmetric synthesis of 12-hydroxyheptadecatrienoic acid and its 5,6-dihydro- and 14,15-dehydro-derivatives
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Natural 12-hydroxyheptadecatrienoic acid (12-HHT) with an S configuration was synthesised by a Suzuki-Miyaura coupling of C10-C17 iodo alcohol with C1-C9 vinylborane. The iodo alcohol was synthesised by utilising Sharpless asymmetric epoxidation of the corresponding trimethylsilyl alcohol. The method yielded more than 100 mg of 12-HHT. Similarly, syntheses of 5,6-dihydro- and 14,15-dehydro derivatives of 12-HHT, known as HHD and HHTE, respectively, were completed in a stereoselective manner.
- Kobayashi, Yuichi,Morita, Masao,Ogawa, Narihito,Kondo, Daiki,Tojo, Toshifumi
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p. 10667 - 10673
(2016/11/30)
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- Synthesis of (S,5 Z,8 E,10 E)-12-hydroxyheptadeca-5,8,10-trienoic acid (12 S -HHT) and its analogues
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Natural 12S-HHT and its analogues were synthesized for study of structure and activity relationship toward the BLT2 receptor. The Suzuki-Miyaura coupling was used for construction of the 8E,10E-diene moiety of 12S-HHT and analogues of (12R)- and 12-keto-t
- Tojo, Toshifumi,Wang, Qian,Okuno, Toshiaki,Yokomizo, Takehiko,Kobayashi, Yuichi
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p. 1545 - 1548
(2013/08/23)
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- Spectrofluorimetric quantification of malondialdehyde for evaluation of cyclooxygenase-1/Thromboxane synthase inhibition
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The in vitro assay developed by Hartmann and Ledergerber (1995) utilizing the spectrofluorimetric quantification of malondialdehyde after reaction with thiobarbituric acid was modified and used for further investigations. The human whole blood was replaced by a platelet suspension of pig blood, and calcium ionophore A23187 was used instead of collagen for inducing the arachidonic acid cascade. The modified assay represents a simple, time and cost saving method for the evaluation of cyclooxygenase- 1/thromboxane synthase inhibition. The reproducibility and comparability of results is given. Additional experiments allow classification of selective phospholipase A2, cyclooxygenase-1, and thromboxane synthase inhibitors. Further studies of malondialdehyde formation show that the cyclooxygenase and/or the thromboxane synthase are competitively inhibited by reaction products of the cyclooxygenase pathway by a negative feedback mechanism.
- Dannhardt, Gerd,Flemmer, Linda,Hartmann, Rolf W.,Kleber, Alice,Schulze, Elfriede
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p. 359 - 364
(2007/10/03)
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- Thermodynamic and structural characterization of cis-trans isomerization of 12-(S)-hydroxy-(5Z, 8E,10E)-heptadecatrienoic acid by high-performance liquid chromatography and gaschromatography-mass spectrometry
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It is shown that 12-(S)-hydroxy-(5Z,8E,10E)-heptadecatrienoic acid (5-cis-HHT) - a physiological metabolite of arachidonic acid-is acid-catalyzed converted into a less polar substance with its maximum UV-absorption at λ(max)=232 nm and a molar absorptivity of about ε=26 600±200 M-1 cm-1. Using a reversed-phase high-performance liquid chromatographic (HPLC) method this equilibrium reaction (K(c)=1.78±0.05 at pH 1.10 and 298 K) could be thermodynamicly characterized as a pH dependent, exergonic and exothermic reaction according to kinetics of a first order reaction (at pH 1.10 and 298 K: Δ(R)G°=-1.42±0.07 kJ mol-1, Δ(R)H°=-3.50±0.9 kJ mol-1, Δ(R)S°=-7.0±3.0 J mol-1*K, Δ(R)H(f)(≠)=100.0±4.0 kJ mol-1). Kinetic data for several pH-values and temperatures are presented. These data and structural characterization by gaschromatography-mass spectrometry (GC/MS) lead to the conclusion that 5-cis-HHT is isomerized to 12-(S)-hydroxy-(5E,8E,10E)-heptadecatrienoic acid (5-trans-HHT). Copyright (C) 1998 Elsevier Science Ireland Ltd.
- John,Schlegel
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p. 181 - 188
(2007/10/03)
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