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31.
Tsuyoshi Miura Satoshi Tsujino Kohtaro Goto Midori Noguchi Manabu Node Nobuyuki Imai 《Tetrahedron》2005,61(27):6518-6526
The use of the bisfluorous chain-type propanoyl (Bfp) group as a fluorous protective group made it possible to rapidly synthesize the Gb2 and Gb3 oligosaccharide derivatives by a simple fluorous-organic extraction purification. Furthermore, the fluorescence-labeled Gb2 and Gb3 oligosaccharides were prepared as a potential Vero Toxins detecting reagent. 相似文献
32.
The functionalized pyranosyl hetero-olefins , and received a remarkable diastereoselective addition of methyllithium to form adducts, one of which was introduced into a possible synthetic intermediate as for maytansine () along Scheme I. 相似文献
33.
K Yoshino K Goto T Kohno T Morita G Tsukamoto 《Chemical & pharmaceutical bulletin》1990,38(3):676-680
Various asymmetric or cyclic ester derivatives of the phosphonic acid moiety in the calcium antagonist fostedil (KB-944) were synthesized. The coronary vasodilator activity of these compounds was assessed by Langendorff's method. Among them, the ethyl isopropyl ester 12 showed the most potent activity, which was comparable to that of fostedil. 相似文献
34.
Jinghua Zhang Toshiko Nagahama Hiroki Ohwaki Yasuhiro Ishibashi Yuji Fujita Sunao Yamazaki 《Analytical sciences》2004,20(1):37-43
To understand the cause of discoloration of the sea laver "nori," which is found in the Ariake Sea, the concentrations of pigments and elements in the normal and discolored laver samples were determined. In the discolored samples, a decrease in all of the pigments, chlorophyll a and carotenoids, and proteinous pigments, phycobiliproteins, was clearly observed. This was accompanied by a decrease in the content of Fe, Zn, Mn, Cu, and P. Good correlations between these elements and chlorophyll a, as well as between these elements and phycobiliproteins, were confirmed, indicating that, in addition to the deficiency of nitrogen and phosphorus, the deficiency of trace elements (Fe, Zn, Mn, and Cu), which are specifically required for photosynthesis, could be a reason for the discoloration of nori. The cause of elemental deficiency is also discussed. 相似文献
35.
The enantio-controlled synthesis of trans-4,5-benzhydrindan-1-ones was achieved by means of a stereoselective [4+2] cycloaddition of o-quinodimethanes generated by a thermal cleavage of benzocyclobutene derivatives as a key step. The chiral substrates of the thermal reaction were synthesized by a diastereoselective Grignard addition to the chiral O-isopropylideneglyceroketones connected to a benzocyclobutene ring, which were simply prepared from D-mannitol as a chiral source. This approach can provide a new efficient access to A-nor B-aromatic steroidal compounds. 相似文献
36.
The pinacol reaction of beta-halogenated alpha,beta-unsaturated aldehydes was promoted by titanium tetraiodide to give coupling products in good yields with high dl-selectivity. Subsequent reduction with H(2)/Pd-C gave saturated vic-diols in good yields. Heck coupling reaction enabled the displacement of halogens with vinyl groups without the loss of stereochemical integrities. [reaction: see text] 相似文献
37.
Labeling experiments using several deuterated lipids were pursued to study the biosynthesis of macrocyclic isoprenoidal lipids of thermophilic methanogenic archaea, Methanothermobacter thermautotrophicus. The isopropylidene terminal of geranylgeranyl group of monomeric precursor appeared to be important for the CC bond formation at the hydrophobic end in the macrocyclic lipids. A mechanism involving a radical trigger at the allylic methyl group is proposed for this CC bond formation. 相似文献
38.
A catalytic photometric method with a flow-injection system is described for the determination of 9,10-phenanthrenequinone. It is based on the catalytic effect of 9,10-phenanthrenequinone on the redox reaction of 1,2-dinitrobenzene with formaldehyde under alkaline conditions. 9,10-Phenanthrenequinone at the 5.0 x 10(-8)-5.0 x 10(-6)M level can be determined at a rate of 20 samples/hr. The detection limit is 1.0 x 10(-8)M (40 pg in a 10-microl injection). 相似文献
39.
Hidemasa Yamaguchi Yuji Minoura 《Journal of polymer science. Part A, Polymer chemistry》1970,8(6):1467-1479
Optically active N-bornylmaleimide (NBMI) was copolymerized with styrene, methyl methacrylate, and vinylidene chloride with a free-radical catalyst to obtain optically active copolymers. The monomer reactivity ratios for the radical copolymerization of NBMI (M2) with styrene, methyl methacrylate, and vinylidene chloride were: ST-NBMI, r1 = 0.13, r2 = 0.05; MMA-NBMI, r1 = 2.02, r2 = 0.16; VCl2-NBMI, r1 = 1.15, r2 = 0.47. The Q-e values for NBMI were Q2 = 0.48 and e2 = +1.47. The specific rotation and optical rotatory dispersion of these copolymers were measured. The correlation between the specific rotation and composition of these copolymers was not linear. The value of λc for each copolymer was independent of the copolymer composition and the comonomer, being 260 mμ for the St-NBMI system, 262 mμ for the MMA-system, and 260 mμ for the VCl2-NBMI system. The effects of solvents and temperature on the specific rotation of these copolymers were investigated. 相似文献
40.
Liposomes prepared from synthetic amphiphiles. I. Their technetium labeling and stability 总被引:1,自引:0,他引:1
In order to apply liposomes prepared from synthetic amphiphiles containing amino acid residues to radiopharmaceuticals, their labeling with 99Tc or 99mTc and stability in saline or in serum were investigated. These liposomes were highly labeled by embedding stearylamine-diethylenetriamine pentaacetic acid as a ligand of technetium. The labeling was more efficient at pH 7.0 than at pH 4.0 or 8.5. Among these technetium-labeled liposomes tested, liposomes containing the alanine residue were stable in saline or in 50% serum at 37 degrees C for at least 24 h, in contrast to liposomes (phosphatidylcholine: cholesterol = 1:1 molar ratio) whose stability had been enhanced by adding cholesterol. 相似文献