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991.
Various 2'-phenoxymethanesulfonanilide derivatives were synthesized and evaluated for antiinflammatory and analgesic activities. Some compounds bearing an electron-attracting substituent at the 4'-position strongly inhibited adjuvant-induced arthritis in rats and acetic acid-induced writhing syndrome in mice without causing gastro-intestinal irritation. Among them, 4'-cyano-(FK867) and 4'-acetyl-(FK3311) 2'-(2,4-difluorophenoxy)methanesulfonanilides were selected as the candidates for further development.  相似文献   
992.
Summary A new method was developed for preparing an aqueous colloidal dispersion ofΒ-carotene. This method consists of preparing a solid mixture ofΒ-carotene and polyvinylpyrrolidone (PVP) from their chloroform solution by evaporating the solvent and dissolving the mixture into water. From filtration experiment and electron microscopic observation it was found thatΒ-carotene in its aqueous dispersion exists as colloidal particles with a diameter of about 100 ?. Spectroscopic data evidenced thatΒ-carotene is molecularly dispersed in solid of PVP. It was considered that PVP acts as a solid solvent forΒ-carotene and, at the same time, a stabilizing agent for its aqueous dispersion. Instead of PVP, such a hydrophilic-oleophilic substance as methylcellulose, polyvinylmethylether or Aerosol OT could be also used as the dispersing agent. Other materials thanΒ-carotene could be dispersed by similar technique.
Zusammenfassung Es wird eine neue Methode zur Pr?paration einer w?\rigen Kolloid-Dispersion vonΒ-Carotin beschrieben. Diese Methode besteht aus Herstellen einer festen Mischung ausΒ-Carotin und Polyvinylpyrrolidon (PVP) aus der Chloroforml?sung durch Verdampfen des L?sungsmittels und anschlie\ende L?sung der Mischung in Wasser. Aus Filtration und elektronenmikroskopischen Aufnahmen l?\t sich zeigen, da\ dasΒ-Carotin molekulardispers im festen PVP verteilt ist. Das PVP wirkt offensichtlich als festes L?sungsmittel fürΒ-Carotin und gleichzeitig als stabilisiertes Agens für die w?\rige Dispersion. Anstelle von PVP k?nnen auch derartige hydrophile-oleophile Substanzen wie Methylcellulose, Polyvinylmethyl?ther oder Aerosol OT verwendet werden. Es k?nnen auch andere Materialien alsΒ-Carotin auf gleiche Weise dispergiert werden.
  相似文献   
993.
994.
995.
Too unstable for asymmetric deprotonation, alpha-sulfenyl carbanions can undergo asymmetric substitution reactions with high stereoselectivity [Eq. (1)]. The key to the asymmetric induction is the dynamic kinetic resolution of the complex formed between the organolithium compound and a chiral ligand, the most effective of which were bisoxazoline derivatives.  相似文献   
996.
The effects of separators on the self-discharge behavior and the suppression of self-discharge by a sulfonated polyolefin separator were investigated with test cells. The experimental results indicate that a sulfonated polyolefin separator effectively suppresses the self-discharge reaction in nickel-metal hydride batteries. It is also found that a sulfonated polyolefin sheet does not necessarily need to be sandwiched by positive and negative electrodes to act as a separator; it can be placed anywhere within a cell to suppress the self-discharge reaction. The self-discharge reaction is considered to be suppressed by trapping redox shuttle substances, especially nitrogen-containing compounds, by the separator.  相似文献   
997.
Three different commercial heparins were trinitophenylated with 2,4,6-trinitrobenzenesulfonic acid (TNBS) under aqueous conditions. The reaction kinetics of amino groups in heparin with TNBS showed that the reactivities of amino groups were significantly different for free amino groups on heparin, compared to reactivities in peptides and amino acid residues attached to heparin molecules. With TNBS, unreactive amino groups were always present during the reaction.  相似文献   
998.
The synergic extraction of La(III), Nd(III), Sm(III), Tb(III) and Lu(III) with 0.1M acetylacetone (Hacac) and 1,10-phenanthroline (phen) in benzene was studied. The adduct formation constant, s, for RE(acac)3 (phen) in benzene was determined. The s decreases with inceasing atomic number of RE(III). The s in different organic solvents can be predicted in connection with the activity coefficients of the solutes, and the validity of this prediction is confirmed by good agreement with the experimental values of s in carbon tetrachloride and heptane.  相似文献   
999.
[reaction: see text] A thiolate/alkyl halide coupling reaction in aqueous media provides a one-step synthesis of fullerene glycoconjugates bearing five carbohydrate groups in good yield by using stoichiometric amounts of reactants, without recourse to hydroxy group protection. The sulfide-connection methodology is also useful for synthesis of simpler amphiphilic fullerene molecules, such as one bearing five carboxylic acid groups.  相似文献   
1000.
The behavior of salicylic acid-D-alanine conjugate (salicyl-D-alanine) following intravenous, oral and intracecal administration was examined in rabbits, then compared with that of salicylic acid-L-alanine conjugate (salicyl-L-alanine) as reported previously. Following intravenous administration, salicyl-D-alanine eliminated rapidly from the blood, and its blood concentration was almost identical with that of salicyl-L-alanine. In both cases, salicylic acid could not be detected in the blood, indicating that systemic de-conjugation of D-alanine might not occur. Unchanged salicyl-D-alanine was found in the blood mainly following oral and intracecal administration of salicyl-D-alanine. On the other hand, salicylic acid formed extensively following oral and intracecal administration of salicyl-L-alanine, suggesting that the presystemic de-conjugation of D-alanine and L-alanine was unequal. Furthermore, in vitro incubation of salicyl-D-alanine with cecal content, in which the major source of salicyl-L-alanine hydrolysis is found, showed that the hydrolysis of salicyl-D-alanine was negligible in rabbit intestinal microorganisms.  相似文献   
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