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31.
The title compound a novel cyclophane containing p-tropoquinone, was synthesized starting from 5-methoxytropolone and its physical properties were discussed comparing with those of 3,7-dimethyl-p-tropoquinone and p-benzoquinonophane. The reduced quinone character exhibited by was ascribed to the intramolecular CT interaction and the deformation of the quinone ring. 相似文献
32.
Radical iodine atom transfer [3 + 2] cycloaddition with various alkenes using dimethyl 2-(iodomethyl)cyclopropane-1,1-dicarboxylate and 1,1-bis(phenylsulfonyl)-2-(iodomethyl)cyclopropane as new precursors of a homoallyl radical species smoothly proceeds to give functionalized cyclopentane derivatives in good yields. 相似文献
33.
The binding of a chiral quaternary ammonium ion to a cyclopeptide containing aromatic amino acid subunits is affected not only by the configuration of the cation but also by the configuration of the chiral counterion. Analysis of the binding equilibria shows that complex formation involves interaction of the whole ion pair with the host indicating that steric requirements of the anion influence complex geometry and stability. 相似文献
34.
The removal of excess reagent extracted into an organic phase in the solvent extraction of a metal complex anion with a quaternary ammonium ion is discussed. With a given chelating ligand (HO—R—SO3H), the order of extractability is HO—R—SO3- > M(OR—SO3)n- > X- > -O—R—SO3- when an anion such as nitrate or halide is added. If suitable amounts of the anion are added, only the excess of reagent can be removed. The principle is applied to the extraction with zephiramine of the cobalt complex anion formed with 2-nitroso-1-naphthol-4-sulfonic acid. Micro amounts of cobalt in pure nickel salts were determined spectrophotometrically. 相似文献
35.
Sulfate ion in river water is determined by flow injection analysis at a rate of 30 samples per hour; the sulfate contents are typically less than 30 ppm. The reagent solution contains dimethylsulfonazo-III, barium chloride, potassium nitrate and chloroacetate buffer in 70% () ethanol, and is saturated with barium sulfate. The aqueous carrier stream is also saturated with barium sulfate. The sample is filtered and treated with Amberlite IR120-B cation-exchanger before injection into the carrier stream, and the decoloration of the barium—dimethylsulfonazo-III complex by sulfate is measured at 662 nm. The calibration graph is linear over the range 0–30 μg ml-1 for sulfate in water. 相似文献
36.
The palladium catalysed condensation of Grignard reagents with silyl derivatives of 8-bromopurine nucleosides and 8-bromoadenosine-3′,5′ cyclic monophosphate is a convenient method for the preparation of free 8-alkylpurine nucleosides and 8-alkyladenosine-3′,5′ cyclic monophosphate. 相似文献
37.
M Yoshida M Shimokura Y Fujiwara T Fujisaki K Akaji Y Kiso 《Chemical & pharmaceutical bulletin》1990,38(2):382-388
Alpha-human atrial natriuretic peptide (alpha-hANP) was synthesized by assembling six peptide fragments in solution followed by deprotection with HF and subsequent air-oxidation. The trimethylbenzyl group was employed as an S-protecting group of cysteine. The HF-dimethylselenide-m-cresol system was employed as a final deprotecting reagent and, at the same time, as a reducing reagent of Met(O). Synthetic alpha-hANP elicited potent diuretic and natriuretic activity in rats. 相似文献
38.
Wender PA Baryza JL Bennett CE Bi FC Brenner SE Clarke MO Horan JC Kan C Lacôte E Lippa B Nell PG Turner TM 《Journal of the American Chemical Society》2002,124(46):13648-13649
Macrocycle 1 is a new highly potent analogue of bryostatin 1, a promising anti-cancer agent currently in human clinical trials. In vitro, 1 displays picomolar affinity for PKC and exhibits over 100-fold greater potency than bryostatin 1 when tested against various human cancer cell lines. Macrocycle 1 can be generated in clinically required amounts by chemical synthesis in only 19 steps (LLS) and represents a new clinical lead for the treatment of cancer. 相似文献
39.
Berger A Djukic JP Pfeffer M de Cian A Kyritsakas-Gruber N Lacour J Vial L 《Chemical communications (Cambridge, England)》2003,(5):658-659
In the presence of large amounts of [Me4N]Cl, the reaction of ortho-chloromercurated 2-[(eta6-phenyl)tricarbonylchromium]pyridine with mu-chloro cyclopalladated aromatic compounds yields a series of new heteroleptic heterodinuclear cis-(C--N)2Pd(II) complexes, which are valuable precursors of planar chiral cyclopalladated (eta6-arene)Cr(CO)3 complexes. 相似文献
40.
Komatsu H Citterio D Fujiwara Y Minamihashi K Araki Y Hagiwara M Suzuki K 《Organic letters》2005,7(14):2857-2859
[structure: see text] The jewel pendant ligand has multiple chromogenic units combined in a single molecule with the dyes linked to a semiselective binding site by three heteroatoms (O, N, S) having different HSAB characteristics, to indicate diverse response to individual transition metal ions. Using a single-molecular multianalyte sensor, multiple analytes could be determined with a minimal sensing system. 相似文献