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1.
Peter Schuster 《Monatshefte für Chemie / Chemical Monthly》1967,98(4):1310-1322
Zusammenfassung Die -Elektronenstrukturen einiger Iminophosphorane werden in Form der mittels der HMO-Methode berechneten Moleküldiagramme angegeben und unter Verwendung des zur Verfügung stehenden experimentellen Materials diskutiert. Die dazu erforderlichen Parameter wurden zum Teil abgeschätzt (Coulombintegrale: P und N), zum Teil mit Hilfe derHelmholtzschen Näherung berechnet (Resonanzintegral: PN).
Mit 7 Abbildungen
Herrn Prof. Dr. Dr. h. c.Friedrich Wessely in Verehrung und Dankbarkeit zum 70. Geburtstag gewidmet. 相似文献
The -electron structures of several iminophosphoranes are calculated with the HMO-Method and presented as molecular diagrams. They are discussed with the aid of the available experimental material. The necessary HMO-parameters were partly estimated (Coulomb integrals: P, 3 d and N) and partly calculated using theHelmholtz approximation (Resonance integral PN).
Mit 7 Abbildungen
Herrn Prof. Dr. Dr. h. c.Friedrich Wessely in Verehrung und Dankbarkeit zum 70. Geburtstag gewidmet. 相似文献
2.
Conclusions The addition of thioacetic acid to the
5 bonds of 16- and 16-mercapto-3-hydroxypregn-5-en-20-one 3,16-diacetates (II) and (III) under radical conditions gives not only trans-diaxial addition products-6,16- and 6,16-dimercapto-3-hydroxy-5o;-pregnan-20-one 3,6,16-triacetates (IV) and (V) -but also cis-addition products-6,16- and 6,16-dimercapto-3-hydroxy-5-pregnan-20-one 3,6,16-triacetates (VI) and (VII).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 405–411, February, 1969. 相似文献
3.
The effect of representing dielectric properties in terms of the complex polarizability c = – i is examined. Loss curves ( and tan ) are shifted towards higher frequencies, revealing the existence of new relaxations and allowing the clarifications of ones already known. We have calculated the shift ratios (at maximum or tan )/ (at maximum or tan ) from the more conventional empirical equations representing the dielectric behavior. Some examples are given. 相似文献
4.
Zusammenfassung Im Rahmen von Untersuchungen zur Bromierung von Propiophenon wurde eine infrarotspektrophotometrische Methode zur Bestimmung von -Brompropiophenon in Gegenwart von -Dibrompropiophenon und Propiophenon entwickelt. Die Methode ist genau und schnell. -Brompropiophenon und -Dibrompropiophenon wurden erstmalig durch ihre Infrarotabsorptionsspektren chatakterisiert.
Summary In the course of investigations on the bromination of propiophenone an infra-red spectrophotometric method has been developed for the determination of -bromopropiophenone in the presence of -dibromopropiophenone and propiophenone. The method is precise and rapid. -Bromopropiophenone and -dibromopropiophenone have been characterized by their infra-red absorption spectra for the first time.相似文献
5.
Sanyo Hamai 《Journal of inclusion phenomena and macrocyclic chemistry》1995,23(3):245-253
The oxidation of iodide to I
3
–
by oxygen dissolved in water containing HClO4 has been found to be accelerated by -cyclodextrin (-CD). Among -, -, and -CDs, -CD is the most effective mediator for the oxidation reaction of iodide by oxygen. The oxidation rate of iodide is first order in the concentrations of -CD and HClO4, whereas it is second order in the KI concentration.Part of this work was carried out at Department of Physics, Miyazaki Medical College, Miyazaki 889-16, Japan. 相似文献
6.
The reaction of hydrazides of adenylyl- or hypoxanthinyl-9-alkylcarboxylic acids with sodium nitrite in acid media gives reactive azides of purinyl-9-alkylcarboxylic acids which condense with ()-aminocarboxylic and ,-diaminocarboxylic acids to give N(N)-(adenylyl-9-alkanoyl) aminocarboxylic, N-(adenylyl-9-)- and N-(hypoxanthinyl-9-alkanoyl)-,-diaminocarboxylic acids. The deamination of N-(adenyl-yl-9-alkanoyl)aminocarboxylic acids gives N-(hypoxanthinyl-9-alkanoyl)aminocarboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 126–130, January, 1985. 相似文献
7.
Conclusions The ethyl esters of- and'-oxodehydrodesthiobiotin when reacted with thioacetic acid in the presence of BF3 etherate respectively give the ethyl esters of-thiooxo- and, -diacetytmercaptodehydrodesthiobiotin.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 954–956, April, 1978. 相似文献
8.
Summary The acyl -D-glucopyranoside, the acyl -D-xylopyranoside, the acyl D- and L--arabinopyranosides, and the acyl -D-lactoside of 18-glycyrrhetic acid, and also the acyl -D-lactoside of 18-glycyrrhetic acid have been synthesized. The acid and alkaline hydrolysis of the compounds obtained has been studied.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 1, pp. 13–19, 1968 相似文献
9.
Conclusions When heated in the presence of a catalytic amount of BF3 etherate,-trifluoromethyl--diethylamino--fluoroacrylic acid N, N-dimethylamide is reversibly isomerized to-trifluoromethyl--dimethylamino--fluoroacrylic acid N, N-diethylamide. The methyl esters of-trifluoromethyl--diethylammo--fluoroacrylic acid and-trifluoromethyl--phenoxy--fluoroacrylic acid N,N-dimethylamide are not isomerized under the same conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.1, pp.137–141, January, 1976. 相似文献
10.
W. Pilz und Ilse Johann 《Fresenius' Journal of Analytical Chemistry》1965,210(2):113-123
Zusammenfassung Es wird eine neue Methode zur spezifischen Bestimmung von freiem -Naphthol in Gegenwart eines großen Überschusses von -Naphthylesteremulsion beschrieben. Alle notwendigen reaktionskinetischen und optischen Bedingungen werden untersucht. Die Methode eignet sich besonders gut zur enzymatischen Analyse von Fermenten, die -Naphthylester hydrolysieren. Nach genauer Beschreibung von Arbeitsvorschriften werden folgende Anwendungsbeispiele ausgeführt: a) die Bestimmung von freiem -Naphthol in rohen -Naphthylesterpräparaten, b) die Bestimmung von Enzymaktivitäten: Substratvariation im menschlichen Serum, c) Verwendung als Suchreaktion: Ortung der -Naphthylpropionat spaltenden Fermente und Proteine des menschlichen Serums durch biologische Analyse der Eluate nach präparativer Stärkebreielektrophorese. Die Empfindlichkeit der Methode beträgt mindestens 0,1 Mol -Naphthol; die Störanfälligkeit ist minimal.
Meinem verehrten Lehrer Herrn Univ. Prof. Dr. Alois Musil zum 65. Geburtstag gewidmet. 相似文献
Summary A new method is described for the specific determination of free -naphthol in presence of a large excess of emulsions of -naphthol esters. The kinetics of the reaction and all optical conditions are tested. The method is applicable to the determination of esterases which hydrolyse -naphthol esters. The following examples for the use of the method are described: a) determination of free -naphthol in industrial -naphthol ester preparations, b) determination of esterase activities; c) application as finding test: localisation of the -naphthol propionic acid ester hydrolysing esterases and proteins of human serum by biological analysis of the eluates after preparative starch electrophoresis. The sensitivity is at least 0.1 Mol of -naphthol; the security is optimal.
Meinem verehrten Lehrer Herrn Univ. Prof. Dr. Alois Musil zum 65. Geburtstag gewidmet. 相似文献
11.
1,3-Skeletal rearrangement of N-substituted ketimines via a possible intimate ion pair is discussed. (CH3)3SiCH=C=O (1) reacts with N-(aziridinyl)-triphenylphosphinimine (2) to give N-(1-aziridinyl)-2-trimethylsilylketen-1-imines (3). The compounds3 b, c are thermally labile and do not undergo 1,3-rearrangement but a retro-ene type reaction to yield (CH3)3SiCH2CN and 2,3-diphenyl-2H-azirine (4). Diphenylketene (5) reacts with N-(N, N-dialkylamino)-triphenylphosphinimines (6) to yield -(N-disubstituted-amino)-nitriles (7). , -Dimethyl--(triphenylphosphinimino)-acetonitrile (9) reacts with (5) at room temperature to form , -dimethyl--(2, 2-diphenylketen-1-imino)-acetonitrile (10) which rearranges at 80° to dimethyl diphenylsuccinonitrile (11). The reaction of5 with 7-(triphenylphosphinimino)-7-azabicyclo[4.1.0]heptane (12) gives tetraphenylsuccinonitrile13 and 7-(7-azabicyclo[4.1.0]heptane)-, -diphenylacetonitrile (14). Finally the synthesis of N-acylketenimines (16) from (5) and acyltriphenylphosphinimines (15) is reported.
38. Mitt.:Chr. Ivancsics undE. Zbiral, Mh. Chem.106, 839 (1975). 相似文献
38. Mitt.:Chr. Ivancsics undE. Zbiral, Mh. Chem.106, 839 (1975). 相似文献
12.
P. Vassileva-Alexandrova 《Mikrochimica acta》1970,58(5):1039-1044
Résumé On a élaboré une méthode spectrophotométrique de détermination de l'analgène au moyen de chlorure de fer-III et de l',-dipyridyle. En milieu alcalin, l'analgène réduit le fer-III en fer-II. L',-dipyridyle forme avec le fer-II un composé complexe rouge vif. La densité optique de la solution analysée est proportionnelle à la concentration de l'analgène. On effectue les mesures à 520 nm. Dans l'analyse de 18 substances pharmaceutiques, la détermination de l'analgène fut gêne par le phénylbutazon (le rapport étant supérieur à 1 1) et par le pyramidon.
Spectrophotometric determination of Analgene by means of iron(III) chloride and ,'-dipyridyl
Summary A spectrophotometric method of determining Analgene by means of iron(III) chloride and, dipyridyl has been worked out. The analgene (in alkaline medium) reduces the Fe(III) to Fe(II). The,-dipyridyl produces a bright red complex compound with Fe(II). The optical density of the solution being analyzed is proportional to the concentration of the analgene. The measurement is made at 520 nm. In 18 pharmaceutical preparations, the determination of the analgene was impaired by phenylbutazone (ratio above 1 1) and by pyramidon.
Zusammenfassung Eine spektrophotometrische Methode zur Bestimmung von Anaigen [1-Phenyl-2,3-dimethyl-4-(N-methyl-N-methansulfonsäure)-5-pyrazolon] mit Hilfe von Eisen(III)-chlorid und,-Dipyridyl wurde ausgearbeitet. In alkalischem Milieu reduziert Anaigen das Eisen zur zweiwertigen Stufe; dieses bildet dann mit,-Dipyridyl einen lebhaft rot gefärbten Komplex. Die Farbintensität ist der Konzentration proportional. Sie wird bei 520 nm gemessen. Unter 18 geprüften pharmazeutischen Substanzen wird die Reaktion von überschüssigem Phenylbutazon sowie von Pyramidon gestört.相似文献
13.
V. V. Mezheritskii A. L. Vasserman G. N. Dorofeenko 《Chemistry of Heterocyclic Compounds》1972,8(9):1050-1052
Pyrylium salts with a free (active) position and different kinds of substituents in the, positions of the pyrylium ring were obtained by the reaction of acetals of aroylacetaldehydes with ketones and phenols.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1163–1165, September, 1972. 相似文献
14.
Levina E. V. Andriyashchenko P. V. Kalinovskii A. I. Stonik V. A. 《Russian Chemical Bulletin》2001,50(2):313-315
Two new steroid compounds, 3,6-dihydroxy-5-cholesta-9(11),24-dien-23-one 3-sulfate and 3,6-dihydroxy-5-cholest-9(11)-en-23-one 3-sulfate, were isolated from the Pacific starfish Lysastrosoma anthosticta as the corresponding sodium salts and identified. Two previously known glycosides of 24(S)-5-cholestane-3,6,8,15,24-pentol were also isolated and identified as sodium 24-O--d-glucopyranoside 6"-sulfate (pycnopodioside C) and sodium 24-O--d-xylopyranoside 4"-sulfate (luridoside A). 相似文献
15.
The temperature dependence of limiting apparent molal volumes ° in water for some alcohols (methanol, ethanol, 1-propanol, 2-butanol, 3-pentanol, 3-hexanol, 2,5-hexanediol, cyclopentanol, cyclohexanol, cycloheptanol, and 1,4-cyclohexanediol) and ethers (trimethylene oxide, tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, 1,3-dioxepane, 1,3,5-trioxane, dimethoxymethane, 1,2-dimethoxyethane, diethoxymethane, and diethyl ether) has been studied in the temperature range 10–50°C by means of an automatic digital-readout dilatometer. Values of the thermal expansion coefficient * = (1/°)(°/T)p have been obtained at several temperatures and discussed together with literature data on expansibilities of related compounds. The data show a wide spectrum of values of * at low temperatures which is narrowed at the higher ones. The expansibilities of monofunctional alcohols increase with increasing temperature; the opposite effect is observed for polyhydric alcohols. The *'s of ethers are very slightly temperature dependent and are much higher, at low temperature, than those of alcohols having the same ratio ofn
o/nc. These results are discussed in terms of solutewater interactions, and a possible interpretation is put forward. 相似文献
16.
A systematic study of the dynamic shear modulusG
*=G+G in three poly(alkyl methacrylates) (PEMA, PnPMA, PnBMA) at frequencies between 0.001 and 500 rad/s is presented. As the splitting frequencies s are low, aging effects can be observed in the splitting region. There is a systematic shift of the splitting frequency s to lower values with increasing length of the alkyl side group. In PnBMA a separate shear appearance is observed about two frequency decades below the local mode . This is discussed in terms of the concept of minimal cooperativity. Aging effects are: Shift of the maximum loss frequency to lower values, peak sharpening of the relaxation, and intensity changes of and . These effects are discussed in terms of the sequential aging concept. Aging leads to a pronounced bending of the traces upwards from the equilibrium line in the Arrhenius diagram. These non-equilibrium phenomena are promoted by the small slope m=d(log )/dT of the trace in the splitting region.Dedicated to Prof. E. W. Fischer at the occasion of his 65th Birthday Lieber Herr Fischer, die Hallenser Polymerphysiker danken Ihnen aufrichtig für die warmherzige und effektive Förderung der Polymerwissenschaften im Raum Halle-Merseburg. 相似文献
17.
I. A. Sukhina M. A. Agzamova B. A. Imomnazarov M. I. Isaev 《Chemistry of Natural Compounds》2000,36(4):373-376
Cyclosiversigenin 6-O--L-rhamnopyranoside and 6-O--D-glucopyranoside were isolated fromAstragalus coluteocarpusBoiss. (Leguminosae) andAstragalus dissectusB. Fedtsch. et N. Ivanova, respectively. Cyclosiversigenin 5-O--L-rhamnopyranoside was shown to be an artifact forAstragalus coluteocarpus.Thus, the cyclosiversigenin 6-O--D-glucopyranoside that was isolated from certainAstragalusspecies is hypothesized also to be an artifact. Glycosylation of the 6 -hydroxyl group of cycloartanes by D-glucose and D-xylose, in contrast with other substituents, does not change the low-field position of the PMR signal of the 4-CH
3
group (1.65 2.01 ppm) that is caused by the influence of deuteropyridine directly on the 6 -hydroxyl. Obviously one of the hydroxyls of the -D-glucopyranoside or -D-xylopyranoside residues has the same effect in this instance. 相似文献
18.
A. A. Panasenko E. C. Gorincioi A. N. Aricu E. A. Barcari K. Deleanu P. F. Vlad 《Russian Chemical Bulletin》2004,53(12):2700-2705
One- and two-dimensional homo- and heteronuclear correlation proton, carbon, proton—proton, and proton—carbon NMR spectra of fifteen drimanic sesquiterpenoids: 11,12-dibromodrima-5,8-dien-7-one, drim-8-en-7-one, 11-hydroxydrim-8-en-7-one, 11,12-dihydroxydrim-8-en-7-one, 11-hydroxy-11,12-epoxydrim-8-en-7-one, 11-hydroxy-11,12-epoxydrim-8-en-7-one, 8,9-epoxydriman-7-one, 8,9-epoxydriman-7-ol, 11,12-diacetoxydrim-8-en-7-ol, drimane-7,8,11-triol, 7,8-isopropylidenedioxydriman-11-al, 9, 11-dihydroxydrim-7-en-6-one, drimane-7,8,9-triol, drimane-7,8,11-triol, and drim-8-ene-7,11,12-triol were studied. The proton and carbon chemical shifts were assigned.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2589–2594, December, 2004. 相似文献
19.
V. I. Grishkovets D. Yu Sidorov L. A. Yakovishin N. N. Arnautov A. S. Shashkov V. Ya. Chirva 《Chemistry of Natural Compounds》1996,32(3):360-365
From the leaves of Algerian ivyHedera canariensis Willd. (fam. Aralaceae) we have isolated 13 triterpene glycosides: the 3-O--L-arabinopyranosides of oleanolic acid (A), of echinocystic acid (B1), and of hederagenin (B2); the 3-O-[O--L-rhamnopyranosyl-(2)--L-arabinopyranoside]s of oleanolic acid (C), of echinocystic acid (D), and of hederagenin (E1); the 3-O--L-rhamnopyranoside] 28-O-[O--L-rhamnopyranosyl-(14)--gentiobioside of hederagenin (G1); the 3-O-[O--L-rhamnopyranosyl-(12)--L-arabinopyranoside] 28-O--gentiobioside of hederagenin (G3); the 3-O-[O--L-rhamnopyranosyl-(12)--L-arabinopyranoside] 28-O-[O--L-rhamnopyranosyl-(14)--gentiobioside]s of oleanolic acid (G2), of echinocystic acid (H1), and of hederagenin (H2); the 3-O-[O--L-rhanmopyranosyl-(12)--D-glucopyranoside] 28-O-(O--L-rhamno-pyranosyl-(14)--gentiobioside] of hederagenin (H2); and the 3-O-(O--L-rhamnopyranosyl-(12)-O-gentiobiosyl)-O-(14)--L-rhamnopyranosyl-(12)-a-L-arabinopyranoside] of hederagenin (G4). The structures of the substances isolated have been established on the basis of chemical transformations and13C NMR spectroscopy.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 377–383, May–June, 1996. Original article submitted December 3, 1995. 相似文献
20.
N. A. Generalov B. V. Kuksenko S. A. Losev A. I. Osipov 《Theoretical and Experimental Chemistry》1971,4(3):200-202
A model of a truncated harmonic oscillator with equidistant levels and one-quantum transitions is applied. The balance equations for O2 have been solved numerically with 26 levels, with the transition probabilities taken as P
k,k
+1k exp (k) P
10, in which k is the number of the level and is an adjustable parameter that takes account of the anharmonicity. A Boltzmann distribution is obtained up to level 19 with =0, but for 0 there are deviations from that distribution in lower levels. Levels with k=1, 2, 3 are populated with relaxation times substantially less than the relaxation time for the vibrational energy. Dissociation depletes levels with k 19. 相似文献