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101.
M. Fujiwara T. Okano T. -H. Nakashima A. A. Nakamura G. Sugihara 《Colloid and polymer science》1997,275(5):474-479
For a sodium salt of α-sulfonatomyristic acid methyl ester (14SFNa), one of the α-SFMe series surfactants, critical micellization
concentration (CMC), solubility and degree of counterion binding (β) were determined by means of electrocon-ductivity measurements
at different temperatures (at every 5 °C) ranging from 15 to 50 °C. The phase diagram of 14SFNa in pure water was constructed
from the CMC- and solubility-temperature data, in which the Krafft temperature (critical solution temperature) was found around
0 °C. The changes in the Gibbs energy, ΔG
0
m, enthalpy, ΔH
0
m, and entropy, ΔS
0
m, upon micelle formation as a function of temperature were evaluated taking βvalues into calculation.
Received: 28 August 1996 Accepted: 5 November 1996 相似文献
102.
Wang J Zhou Y Wang AF Zhang SH Ning L He PG Fang YZ 《Analytical and bioanalytical chemistry》2005,382(1):198-203
A reliable and reproducible method, capillary zone electrophoresis with amperometric detection (CZE–AD), has been developed for separation and quantification of levodopa methyl ester (LDME) and its biotransformation products levodopa (L-DOPA) and dopamine (DA) in rat serum. A carbon-disk electrode was used as working electrode. The optimum conditions for CZE detection were 50 mmol L–1 phosphate solution at pH 7.0 as running buffer, 17 kV as separation voltage, 1.0 V (vs Ag/AgCl, 3.0 mol L–1) as detection potential, and sample injection for 8 s at 17 kV. The linear ranges were from 2.4×10–2 to 2.2 g mL–1
for LDME, 2.9×10–1 to 49.5 g mL–1 for L-DOPA, and 1.4×10–2 to 1.5 g mL–1 for DA with correlation coefficients of 0.9997, 0.9994, and 0.9999, respectively. The detection limits for LDME, L-DOPA, and DA were 14.6, 98.0, and 9.7 ng mL–1, respectively. Recoveries were 80.3% for LDME, 93.5% for L-DOPA, and 86.5% for DA. This method was applied to serum samples after intravenous injection of LDME and L-DOPA to rats. 相似文献
103.
Michael I. Rosenthal Anthony W. Czarnik 《Journal of inclusion phenomena and macrocyclic chemistry》1991,10(1):119-126
The ability of cyclodextrins to effect rapid transacylations of bound substrates has been well studied. One important difference between cyclodextrin and enzyme-mediated transacylation is the pH required. Because the pK
a of a cyclodextrin secondary-side hydroxyl group is about 12, transacylations are accelerated in the presence of cyclodextrin under basic conditions (pH > 10.5). In 1988, our group reported the synthesis of cyclodextrin with attached cyclen-Co(III) complexes; significant acceleration in the reaction withp-nitrophenyl acetate was observed only with the primary side derivative. Of course, metalloenzymes utilize M2+ and not M3+ catalytic centers; in addition, large rate accelerations in the transacylations of both activated and unactivated substrates have been observed previously in systems utilizing M2+ ions (e.g., Zn, Cu, Ni) as well as M3+ ions (e.g. Co, Ir, Cr). In this paper, we describe the ability of CD-cyclen-M2+ conjugates to transacylate activated esters, amides, and phosphates. In addition, the ability of the apoenzyme mimic to effect transacylations was examined. 相似文献
104.
S. G. Mikhalenok N. M. Kuz'menok A. M. Zvonok 《Chemistry of Heterocyclic Compounds》2005,41(8):977-986
It was established that, in addition to ethyl 4-aryl-3-(2,3-epoxyalkanoyl)-4,5-dihydro-1H-pyrazole-5-carboxylates, the reaction
of diazoacetic ester with β-arylacryloyloxiranes also gives ethyl 4-aryl-3(5)-(3-hydroxy-2-methylalkanoyl)-1H-pyrazole-5(3)-carboxylates.
The latter are formed from the tautomeric ethyl 4-aryl-5-(2,3-epoxyalkanoyl)-4,5-dihydro-1H-pyrazole-3-carboxylates as a result
of intramolecular oxidative-reductive disproportionation.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1150–1160, August, 2005. 相似文献
105.
106.
合成了3种主链含己烷雌酚的生物可降解的聚磷酸酯,结构经IR,^1HNMR和元素分析鉴定,通过水接触角的测定研究了聚合物的亲水-疏水性能,以pH值变化表征了聚合物的体外水解速率。初步的体外实验表明,此类聚磷酸酯具有较好的体外抗艾氏腹水癌活性。 相似文献
107.
Investigation of the root extract of Antidesma pentandrum var. barbatum led to the isolation of seven new compounds, antidesmol ( 1 ), antidesmanins E ( 2 ) and F ( 3 ), antidesnone ( 4 ), antidesnol ( 5 ), barbatumols A ( 6 ) and B ( 7 ), together with 14 known compounds including sodium aristolochate‐I ( 10 ) and aristolochic acid‐I methyl ester ( 11 ). 相似文献
108.
3-(3-Aryl-4-formyl-1-pyrazolyl)propionic acids are converted by Knoevenagel condensation under conditions of microwave activation
into 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]acrylic acids. Reduction of the latter with hydrazine hydrate in the presence
of Raney nickel gives 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]propionic acids.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 686–690, May, 2006. 相似文献
109.
Rosin glycerin ester and its bromide were prepared from natural renewable rosin, glycerin and liquid bromine which were first
subjected to an esterification reaction, followed by an addition reaction. Their structures were characterized by an infrared
(IR) spectrum and their thermal resistance was conducted with thermal gravity (TG) and differential scanning calorimetry (DSC).
It showed that the bromide in the rosin glycerin ester decomposed faster than the ester; hence it may be used as fire-resistant
material. 相似文献
110.
Applying different surface and spreading techniques to form binary monolayers in a different mixing state, the mixing behavior of the three binary systems cholesteryl formiate/stearic acid, cholesteryl acetate/stearic acid, and cholesteryl-n-propionate/stearic acid were investigated and compared.Analyzing the force ()/area (a) isotherms and the equilibrium spreading pressures (e of the binary monolayers, it can be concluded that the components of the three binary systems do not mix within the whole concentration range. The lipids in the binary monolayers are completely immiscible. 相似文献