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11.
12.
HPLC determination of (+)-pseudoephedrine and (-)-ephedrine in Japanese herbal medicines containing Ephedra herb using solid-phase extraction 总被引:2,自引:0,他引:2
Ichikawa M Udayama M Imamura K Shiraishi S Matsuura H 《Chemical & pharmaceutical bulletin》2003,51(6):635-639
We developed a rapid and simple HPLC method combined with solid-phase extraction (SPE) for quantitative analysis of (+)-pseudoephedrine (PEP) and (-)-ephedrine (EP) in Japanese herbal (Kampo) medicines such as Kakkon-to, Sho-seiryu-to, Goshaku-san and Bofu-tsusho-san. SPE was performed on TOYOPAK IC-SP M containing propylsulfonic groups. Determination of PEP and EP was carried out using ion-pair reversed-phase HPLC with sodium dodecyl sulfate. N-Benzyldiethylamine was used as an internal standard. The analytical procedure was validated with regard to specificity, linearity, accuracy, and precision. These data suggest that the analytical method developed in this study is useful for quantitative analysis of PEP and EP in various formulations of Kampo medicine containing Ephedra herb. 相似文献
13.
Mishina V. Yu. Abrashina I. V. Teleshev A. T. Vasyanina L. K. Nifant'ev E. E. 《Russian Journal of Organic Chemistry》2002,38(7):977-981
Phosphorous triamides react with aliphatic diols and dibasic phenols: 1,6-hexanediol, 2,2'-(4-hydroxyphenyl)propane, 1,4-hydroquinone, and 4,4'-dihydroxybiphenyl in the temperature range 80-110°C in diethylene glycol dimethyl ether or without a solvent to afford phosphorus-containing regular high-molecular products having an O2P(NR2) moiety in the monomeric unit. The resulting poly(phosphoramidites) are capable of swelling in organic solvents, and they can be used as macroligands in the catalytic hydrogenation of styrene over rhodium(I) complexes. 相似文献
14.
Atsushi Ikeda Masaru Kawaguchi Yoshio Suzuki Tsukasa Hatano Munenori Numata Seiji Shinkai Akio Ohta Makoto Ohta 《Journal of inclusion phenomena and macrocyclic chemistry》2000,38(1-4):163-170
The calixarene-fullerene interaction,which causes only a slight change in the absorptionspectra, has been substantiated by calorimetricmeasurements: the H° values arecomparable with those obtained from the associationconstants estimated by a spectroscopic method. Furthermore, we determined the association constantbetween homooxacalix[3]arene and [60]fullerenederivatives with a porphyrin moiety by fluorescencespectra. 相似文献
15.
Racemic 2-amino-3-(heteroaryl)propanoic acids (1), mostly with a furan or thiophene nucleus as a heteroaryl group, were synthesized in 48-94% yield by the reduction of 3-(heteroaryl)-2-(hydroxyimino)propanoic acids (5) with zinc dust and formic acid in the presence of a catalytic amount of iron dust at 60 degrees C for 2 h. Under these conditions, unfavorable hydrogenolysis of bromine on the thiophene nucleus does not occur. Traditional N-formylation of the prepared 3-(heteroaryl)alanine (1) with a mixture of formic acid and acetic anhydride afforded 2-(formylamino)-3-(heteroaryl)propanoic acids (6) in 51-95% yield. 相似文献
16.
The aqueous solution of mixture of sodium decyl sulfate (SDeS) and decyltrimethylammonium bromide (DeTAB) has been found to form equilibrium multilamellar vesicles (MLV) spontaneously. We measured the surface tension of the aqueous solution of 1:1 mixture of SDeS and DeTAB as a function of temperature T at various molalities m under atmospheric pressure. The surface density, the entropy of adsorption and the entropy of vesicle formation are evaluated and compared with those of the decyltrimethylammonium decyl sulfate (DeTADeS) aqueous solution system to investigate the role of small counterions in the mechanism of equilibrium vesicle formation. The saturated surface density Gamma (H,C ) vs T curve of the SDeS/DeTAB system sits below that of the DeTADeS system. Therefore, sodium and bromide ions are negatively adsorbed and nevertheless, they neutralize the electric charge of the decyl sulfate ion DeS(-) and the decyltrimethylammonium ion DeTA(+) to some extent to weaken the electrostatic attraction between the polar head groups in the adsorbed film. The net surfactant concentration required for vesicle formation was larger in the SDeS/DeTAB system. Hence, the electrostatic attraction between the polar head groups of the surfactant ions which is one of the major driving forces for vesicle formation is weakened by the presence of the counterions Na(+) and Br(-). Small but distinct changes in the surface density and the entropies of MLV formation of the SDeS/DeTAB system from those of the DeTADeS system were also found. 相似文献
17.
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
18.
Chiral β-dimethylaminoalkylphosphines were prepared starting with amino acids, (S)-alanine, (S)-phenylalanine, (R)-phenylglycine, (S)-valine, and (R)-tert-leucine. The chiral phosphines were found to be highly efficient ligands for a nickel catalyzed asymmetric Grignard cross-coupling reaction (38~94% optical yield). 相似文献
19.
[structure: see text] A highly convergent synthetic route to the FGHIJKLM ring fragment of ciguatoxins has been developed, which relied on extensive use of the B-alkyl Suzuki-Miyaura coupling reaction. 相似文献
20.
The relative stability of various organosulfur radicals is estimated by competitive elimination technique using tributyltin radical and acetophenone derivatives having two different sulfur substituents at α and α positions. 相似文献