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141.
S. Z. Taits O. A. Kalinovskii V. S. Bogdanov Y. L. Gol'dfarb 《Chemistry of Heterocyclic Compounds》1970,6(11):1367-1372
A mixture of isomers corresponding to closing of the ring at the 3 and 4 positions of the thiophene ring is formed during intramolecular acylation of 12-(5-methyl-2-thienyl)-lauryl chloride in a homogeneous medium; the reaction proceeds primarily to favor the formation of the isomer with the larger ring (80%). A method for the synthesis of macrocyclic -alkylcycloalkanones by reductive desulfurization of the corresponding bicyclic ketones, which contain thiophene rings, was developed.See Izv. Akad. Nauk SSSR, Ser. Khim., 2228 (1970) for Communication XI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1467–1472, November, 1970. 相似文献
142.
Fischer indolization of ethyl pyruvate 2-methoxyphenylhydrazone (1) with p-toluene-sulfonic acid in benzene in the presence of an enolizable dicarbonyl or an indolic compound gave either an indole product having an active methine group at C6 or a novel type of 3,6′-biindole compound. Structures of the products were established by NMR spectra and chemical evidence. 相似文献
143.
Desialylated fetuin (asialofetuin) was adopted as a carrier for introducing drugs in parenchymal liver cells. Mitomycin C, as a model guest-compound, was covalently attached to asialofetuin through a spacer of the succinyl group. The asialofetuin-mitomycin C conjugate contained 4.4 w/w% of mitomycin C and liberated it gradually at physiological conditions (t1/2 = 37 h). The survival time of the conjugate in rat blood circulation was significantly smaller than that of the non-desialylated fetuin conjugate; the elimination half-life was 7.3 min after intravenous injection. At 30 min after injection of the conjugate in rats, 40% of the dose was present in the liver. Parenchymal cells in the liver selectively took up the conjugate, which was highly distributed to the lysosomal fraction in the cell. The greater uptake of the conjugate by hepatocytes reflected the increased excretion in the bile; totally 10.4% of the dose was recovered. 相似文献
144.
Several derivatization procedures with o-phthaldialdehyde-N-acetylcysteine (OPA-NAC) were compared for a rapid analysis of primary aliphatic short-chain monoamines in water samples by HPLC using a LiChorospher analytical separation column (100RP18 mm i.d., 5 μm). Both the solution and the solid-support assisted off-line derivatization on C18 SPE cartridges were inadequate options because of beginning degradation processes of the instable isoindol derivatives during their transfer to the analytical column. This problem was precluded with the on-column or solid-support assisted on-line derivatization. In the last mentioned procedure, the derivatization took place in a Hypersil C18 precolumn ( mm i.d., 30 μm) connected with an additional preconcentration step resulting in better detection limits (0.002-0.040 μg ml−1 requiring only 150 μl of water sample) than in the on-column procedure (0.08-0.16 μg ml−1). The improved sample handling, the better control of parameters affecting reaction rates, the fully automation of this method with only 10 min analysis time for each sample are further advantageous. The potential of the solid-support assisted on-line derivatization was outlined and applied to water samples from several sources. Recovery values near 100% were obtained. 相似文献
145.
Vaporisation et dissociation thermique des sulfures de phosphore P4S3, P4S7 et P4S10 a l'etat gazeux
J. Bouix R. Hillel H. Vincent Y. Monteil 《Journal of Thermal Analysis and Calorimetry》1977,12(3):371-382
Résumé Nous avons montré par spectrométrie Raman à chaud et mesure des tensions de vapeur que P4S3 se vaporise de façon congruente tandis que P4S7 et P4S10 se dissocient dès le début de leur vaporisation. P4S7 donne réversiblement P4S3 et soufre. P4S10 se dissocie irréversiblement en P4S7 et soufre. A l'état de vapeur non saturante, P4S3 se dissocie au-dessus de 600° avec formation de phosphore, de soufre et d'autres espèces non identifiées.Nous avons mesuré expérimentalement la capacité calorifique de P4S3 liquide, calculé celle de P4S3 gazeux et son entropie standard. Nous avons aussi estimé l'enthalpie standard de vaporisation de P4S3 à l'aide des mesures des tensions de vapeur saturante. Nous en avons déduit l'entropie standard de P4S3 liquide et son point d'ébullition.
Nous remercions Monsieur Letoffe du laboratoire du Professeur J. Bousquet, INSA de Lyon, 20 Avenue Albert Einstein 401, 69621 Villeurbanne, qui a r6alis6 pour nous les déterminations expérimentales des capacités calorifiques de P4S8 liquide. 相似文献
It is shown by Raman spectroscopy at high temperature and by vapor tensimetric measurements that the vaporisation of P4S3 is congruent, whereas P4S7 and P4S10 dissociate at the beginning of vaporisation. P4S7 gives P4S3 and sulfur reversibly. The dissociation of P4S10 into P4S7 and sulfur is irreversible. Above 600°, in non-saturated vapour the dissociation of P4S3 gives phosphorus, sulfur and some unidentified gaseous species. The heat capacity of liquid P4S3 has been measured. That of gaseous P4S3 and its standard entropy have been calculated. The vaporisation standard enthalpy of P4S3 has been estimated from the experimental results on the saturated vapour pressures. The standard entropy of liquid P4S3 and its boiling point have been derived from these data.
Zusammenfassung Mittels Raman-Spektrometrie bei erhöhter Temperatur und durch Messung der Dampfdrucke wurde festgestellt, daß sich P4S3 verflüchtigt, während P4S7 und P4S10 mit Beginn der Verflüchtigung dissoziieren. P4S7 ergibt reversibel P4S3 und Schwefel. Im Zustand ungesättigten Dampfes dissoziiert P4S3 oberhalb von 600° unter Bildung von Phosphor, Schwefel und anderer nicht identifizierter Substanzen.Die Wärmekapazität von flüssigem P4S3 wurde gemessen, während die vom gasförmigem P4S3 sowie seine Standard-Entropie berechnet wurden. Die Standard-Enthalpie der Verflüchtigung des P4S3 wurde durch Messungen der Sättigungs-Dampfdrucke ermittelt. Daraus wurden die Standard-Entropie des flüssigen P4S3 sowie sein Siedepunkt berechnet.
- - , P4S3 , P4S7 P4S10 . P4S7 P4S3 , P4S10 P4S7 . 600° P4S3 , . P4S3, P4S3 . P4S3. P4S3 .
Nous remercions Monsieur Letoffe du laboratoire du Professeur J. Bousquet, INSA de Lyon, 20 Avenue Albert Einstein 401, 69621 Villeurbanne, qui a r6alis6 pour nous les déterminations expérimentales des capacités calorifiques de P4S8 liquide. 相似文献
146.
Simultaneous determination of cefazolin in rat blood and brain by microdialysis and microbore liquid chromatography 总被引:3,自引:0,他引:3
A sensitive microbore liquid chromatographic method combined with the minimally invasive technique of microdialysis was devised for simultaneously and continuously monitoring the levels of unbound blood and brain cefazolin in rats. Microdialysis probes were inserted into the jugular vein and brain striatum for blood and brain sampling, respectively. Chromatographic conditions consisted of a mobile phase of methanol-acetonitrile-100 mM monosodium phosphoric acid (20:10:70, v/v, pH 4.5) pumped through a microbore reversed-phase column at a flow rate of 0.05 mL/min. The ultraviolet detection wavelength was set at 270 nm. An on-line design allowed direct and continuous analysis of protein-free samples in the dialysate. Microdialysis probes, being home-made, were screened for acceptable in vivo recovery. Chromatographic resolution and detection were validated for response linearity as well as intra-day and inter-day variabilities. This method was then applied to pharmacokinetic profiling of protein unbound cefazolin in both the blood and brain following intravenous administration (10 mg/kg, i.v., n = 6). Rapid appearance of cefazolin in the rat brain striatal dialysate following drug injection suggested good blood-brain barrier penetration. According to a non-compartmental pharmacokinetics model, the area under the concentration (AUC) vs time ratio of cefazolin in rat brain and blood was 6%. 相似文献
147.
Y.A DemchenkoA Razina Z SedlákovaA Sikora J BaldrianM Ilavský 《European Polymer Journal》2002,38(12):2333-2341
Thermotropic polyesters based on 4,4′-alkane-1-ω-diylbis(4-hydroxybenzoic acid) and 4,4′-(pentane-1,5-diyloxy)dibenzoic acid were studied by dynamic mechanical spectroscopy, X-ray scattering, differential scanning calorimetry and polarizing microscopy. The effect of structure changes in the mesogenic group as well as in the flexible spacer, in particular the incorporation of Cl atoms into the mesogen, introduction of ether oxygen into spacer and the number of CH2 groups in spacer was investigated. More complex mechanical and thermal behaviour was found on second heating scan than on first cooling of the isotropic melt; higher values of mechanical functions were observed in the isotropic state than in the nematic state of melts. While an even number of CH2 groups and the presence of ether oxygen in spacer shifts the transition temperatures to higher values, the incorporation of Cl atoms into the mesogen leads to disappearance of ordered structure and the polymers behave as amorphous materials. 相似文献
148.
C.L. Liu X.Y. Wang Z.M. Wang S.S. Li C.T. Xin H.F. Wang B. Li L. Jiang 《Journal of Radioanalytical and Nuclear Chemistry》2001,250(3):587-591
The migration of 99Tc in a weak loess aquifer was investigated in-situ with undisturbed aquifer medium columns. The columns were obtained horizontally at a depth of 3236 m in an Underground Research Facility (URF). Quartz containing 3H (HTO) and 99Tc (in the form of 99TcO4
-) was introduced into one end of the columns and the columns were covered tightly. Aquifer water was introduced into the columns directly from an experimental shaft in the UFR. Effluents from the columns were collected and the activity of 3H and 99Tc were determined with a liquid scintillation analyzer. The breakthrough curves of 3H and 99Tc indicate that 99Tc migrates a little faster than that 3H does in the aquifer. 相似文献
149.
The velocity imaging photoionisation coincidence (VIPCO) technique is shown to be a powerful tool for studies of ion pair formation. Sequential mechanisms are demonstrated for some three-body ion pair formation reactions. Observation of a new type of reaction producing one negatively and two positively charged ions plus an electron is reported. 相似文献
150.
F. Cataldo Y. Keheyan S. Baccaro 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(2):443-450
Anthracite coal and oil bitumen were submitted to γ-radiation at a total dose of 1 MGy and the radiation-processed samples
were studied by FT-IR spectroscopy, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The coal samples
were studied also by TGA coupled with FT-IR spectroscopy of the evolved gases. Thermal analysis has revealed a completely
different behavior of the radiolyzed samples in comparison to the unirradiated samples. Both for coal and bitumen significantly
less volatile fraction was released during the TGA and in both cases a significant increase in the amount of carbon coke produced
at 800-900 °C was observed. The radiation processed bitumen increased significantly its ethyl acetate insolubles content.
These results were interpreted in terms of extensive crosslinking and coalification of the samples under the action of γ-radiation.
The results of this study have been applied to the carbonization process of terrestrial sedimentary organic matter which is
commonly attributed to the action of heat flux from the depth of the Earth but which may be also due to the action of natural
radiation. Other application of the results of the present study is to the complex organic matter present on the surfaces
of comets and meteorites. This complex matter was formed by exposure of simple precursors to a field of high energy radiation
for millions or billions of years and is consequently transformed into coal-like and bitumen-like matter. The same arguments
apply to the carbon grains present in the interstellar and circumstellar medium.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献