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1.
Toshiro Watanabe Tapan Kumar Mazumder Shiro Nagai Keisuke Tsuji Shigeru Terabe 《Analytical sciences》2003,19(1):159-161
A micellar electrokinetic chromatography (MEKC) method was developed for estimating the angiotensin-I converting enzyme (ACE) inhibitory activity by separating the hippuric acid liberated in the ACE reaction mixture in the presence of an inhibitor, captopril. The hippuric acid was successfully separated and detected by MEKC with a 25 mM sodium dodecyl sulfate solution in a 25 mM phosphate-50 mM borate buffer at pH 7.0; the total analysis took about 5 min. A good linear relationship was observed between the inhibitor and the peak area of hippuric acid release. No significant difference in the ACE inhibitory activity (IC50) of captopril (an antihypertensive medicine) or autolyzed-mushrooms (functional foods) was observed between the conventional method and the MEKC method. The MEKC method was found to be a useful technique for a rapid assay of the ACE inhibitory activity. 相似文献
2.
The binding properties of metal ions to a pectic polysaccharide, rhamnogalacturonan II (RG-II), from plant cell walls were analyzed by size-exclusion HPLC/ICP-MS. The dimeric RG-II borate complex (dRG-II-B) from sugar beet and red wine contained 0.8 - 1.1 mol/mol of B, 0.8 - 1.1 mol/mol of Ca, 0.1 - 0.3 mol/mol of Sr, and 0.03 - 0.07 mol/mol of Ba. The treatment of dRG-II-B with Sr2+, Ba2+, Pb2+ or La3+ exchanged the originally present Ca, Sr and Ba. In contrast, monomeric RG-II (mRG-II), which contained approximately 0.1 mol/mol of Ca, formed complexes with La3+, Eu3+, and Lu3+ added to the solution, but did not do so with Ca2+, Sr2+, Ba2+ and Pb2+. The HPLC/ICP-MS and HPLC/RI (refractive index detector) analysis of the partially hydrolyzed mRG-II that was treated with La3+ indicated that the side chains and backbone of mRG-II together form a lanthanoid binding site. 相似文献
3.
Akira Okubo Hiroyuki Kawai Toshiro Matsunaga Tatsuji Chuman Sunao Yamazaki Shozo Toda 《Tetrahedron letters》1980,21(42):4095-4096
T1 gives a clue to assign cis- and trans-methyl carbons in 2-methyl-1-propenyl moiety. 相似文献
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1,3,7,9,11,12,14-Heptazapentacene-2,4,8,10 (14,3,9,12)-tetraones (mixed flavins) were prepared by the cyclization of 1,5-dihydro-8-[N-alkyl-N-(5-nitrouracil-6-yl)-amino-5-deazaflavins with Vilsmeier reagent. The mixed flavins oxidized alcohol under neutral condition in sunlight and a remarkable autorecycling was observed. 相似文献
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[reaction: see text] Dimethylsilanyl [Me2Si(H)] ketene S,O-acetal 6b is an effective nucleophile that retards the undesirable Si+-catalyzed racemic pathway in the oxazaborolidinone-catalyzed asymmetric Michael reaction. Through the further suppression of the Si+-catalyzed pathway by carrying out the reaction in the presence of 2,6-diisopropylphenol and t-BuOMe as additives, enantioselectivity up to 98% ee could be achieved for a variety of acyclic enones. 相似文献
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Masatomo Iwao Toshiro TakeuchiNaotaka Fujikawa Tsutomu FukudaFumito Ishibashi 《Tetrahedron letters》2003,44(24):4443-4446
A highly efficient route to 3,4-diarylpyrrole marine alkaloids has been developed using Hinsberg-type pyrrole synthesis and palladium-catalyzed Suzuki cross-coupling of the 3,4-dihydroxypyrrole bis-triflate derivatives as key reactions. Based on this approach, formal syntheses of permethyl storniamide A and ningalin B, and a total synthesis of lamellarin G trimethyl ether have been achieved. 相似文献