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1.
Palaniswamy Ravi Soundar Divakar 《Journal of inclusion phenomena and macrocyclic chemistry》2003,45(3-4):191-194
Menthone on reduction with sodium dithionite,showed a good amount of mentholformation in the water/DMF system, withincreasing -cyclodextrin (-CD)concentration from 47.0% for 0.1 equivalent of-CD to 93.5% for 1 equivalentof -CD. Increasing hydroxypropyl--cyclodextrin(HP-CD) gave higher menthol/neomenthol (M/N) ratiosfrom 2.8 to 3.5. In the case of pulegone,increasing -CD showed an increase in the formationof menthols in thewater/DMF system from 13.3% for 0.1 equivalent of-CD to 78.1% for 1equivalent of -CD with greater proportions ofneomenthol and neoisomenthol.However, HP-CD which showed only marginalenhancement in the formationof menthol from menthone (32.1–41%), exhibiteda greater proportion of mentholformation in the case of pulegone (55.1%).However, the phase-transfer capabilityof HP-CD was not found to be significant. 相似文献
2.
Jean-François Côté Dany Brouillette Jacques E. Desnoyers Jean-François Rouleau Jean-Marie St-Arnaud Gérald Perron 《Journal of solution chemistry》1996,25(12):1163-1173
The dielectric constants of 1,2-dimethoxyethane, acetonitrile, -butyrolactone, and propylene carbonate were determined from capacitance measurements extrapolated to infinite frequency; ln are reported as a function of pressure up to 80 MPa at 15, 25, 35, 45°C and as a function of temperature in the range 10 to 50°C at 0.10133 MPa. The variation of ln with temperature or pressure can be expressed by a second order polynomial expression. The isothermal compressibilities of the solvents were determined at 25°C from sound velocities, densities, and heat capacities. A simple correlation can be established between ln /P and for most aprotic solvent. 相似文献
3.
G. V. Pirtskhalava M. B. Gorovits T. T. Gorovits N. K. Abubakirov 《Chemistry of Natural Compounds》1980,15(4):446-452
From a methanolic extract of the bulbs ofAllium turcomanicum Rgl. we have isolated a new furostanol glycoside, turoside C (I). An acid hydrolysate was found to contain the aglycone — neoagigenin (II) — and the sugars D-xylose, D-glucose, and D-galactose in a ratio of 1:4:1. The structure of the furostanol (I) has been established by methylation, enzymatic hydrolysis, and oxidative cleavage, and also by the oxidative cleavage of (II), as (25S)-5-furostan-2,3,6,22,26-pentaol 26-O--D-glucopyranoside 3-O-{[O--D-xylopyranosyl-(13)]-[O--D-glucopyranosyl-(12)-O--D-glucopyranosyl-(12)]-O--D-glucopyranosyl-(14)--D-galacto-pyranoside}.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 514–522, July–August, 1979. 相似文献
4.
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
5.
Conclusions The reaction of hypophosphorus acid esters with chloral es studied. A series of esters of bis(-oxy-, , -trichloroethyl) phosphonic acid esters is obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1633–1634, July, 1968. 相似文献
6.
Conclusions Syntheses are reported for ,-dithioalkyldivinyl ketones, which react with ammonia to give -amino--thioalkyldivinyl ketones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2414–2415, October, 1988.The authors thank A. M. Kachurin for assistance in taking the spectra. 相似文献
7.
Zusammenfassung Die frühere Annahme, daß die beiden Modifikationen von-Naphthol den gleichen Schmelzpunkt besitzen und somit einen Grenzfall der Enantiotropie darstellen, wurde durch differentialthermoanalytische Untersuchungen widerlegt. Die beiden Modifikationen stehen zueinander im Verhältnis der Monotropie mit der allerdings nur geringen Schmelzpunktsdifferenz von 0,5°. Auch die IR-Spektren der beiden Kristallformen bestätigen das Vorliegen einer Monotropie.Für die Phasendiagramme der Naphthalingruppe, an denen-Naphthol beteiligt ist, ergeben sich Korrekturen. Da die instabile Mod. II die mit Naphthalin korrespondierende Kristallform ist, liegt in dem System Naphthalin--Naphthol keine lückenlose Mischkristallreihe vor (Typ. I, Roozeboom), sondern es wird eine Mischungslücke gebildet, denn das System besteht aus zwei Mischkristallphasen (Typ. IV). Auch im System-Naphthol--Naphthylamin tritt auf der-Naphtholseite eine bisher nicht erkannte Phasenüberschneidung auf und anstelle von Typ. III wird Typ. V (Roozeboom) gebildet.Schmelzdiagramme ohne Mischkristallbildung-Naphthol--Naphthol,-Naphthol--Naphthylamin) sind von einer Korrektur nur insofern betroffen, als die Kurvenäste der beiden Modifikationen des-Naphthols nicht von einem Punkt ausgehen und der stabile Kurvenast nicht als Mod. II, sondern als Mod. I bezeichnet werden muß.
New results on the polymorphism of-naphthol and its effects on the phase diagrams of the naphthalene group
Summary The earlier assumption that the two modifications of-naphthol have the same melting point and thus constitute a borderline case of enantiotropy was disproved by differential thermoanalytic investigations. The two modifications only have the slight difference in melting point of 0.5°. The IR spectra of the two crystal forms confirm the presence of monotropy.There are corrections for the phase diagrams of the naphthalene group in which-naphthol is involved. Since the unstable modification III is the crystal form corresponding to naphthalene, there is no unbroken series of mixed crystals in the naphthalene--naphthol system (Type I, Roozeboom), but a mixing gap is formed since the system consists of two mixed crystal phases (Type IV). A phase overlap which had not been previously recognized also occurs on the side of-naphthol in the-naphthol--naphthylamine system; the Roozeboom Type V is formed instead of Type III. The melting diagrams of a mixed crystal formation (-naphthol--naphthol,-naphthol--naphthylamine) are affected by a correction only to the extent that the curve branches of the two modifications of-naphthol do not begin at one point and the stable branch of the curve must be designated not as modification II but as modification I.相似文献
8.
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
9.
Conclusions The hydration of the triple bond in 17-ethynyltestosterone, its 17-acetate, and in 17-ethynyland-rost-5-ene-3,17-diol, its 3-acetate and the 3,17-diacetate by treatment with mercuric acetate in the presence of cationite Dowex-50 (H+ form) was accomplished, as a result of which some 20-ketols of the 17-isopregnane series were obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 639–641, March, 1973. 相似文献
10.
Kalojan R. Manolov Dimitar W. Kovatschev 《Monatshefte für Chemie / Chemical Monthly》1969,100(4):1233-1239
Zusammenfassung Die Komplexbildung des p-Methylbenzamidoxims (pMB) mit Ni2+ wurde in neutraler und alkalischer Lösung spektrophotometrisch untersucht. In neutraler Lösung wird ein grüner Komplex 11 gebildet, dessen Bildungskonstante 1=1,12 ist. In alkalischer Lösung werden zwei Komplexe (11 und 12) gebildet mit Bildungskonstanten 1=4·105 und 2=0,2.
Mit 6 Abbildungen 相似文献
Nickel complexes with p-methyl benzamide oxime
The complex formation of p-methyl benzamidoxime with Ni2+ was studied spectrophotometrically in neutral and in alkaline solution. A green complex 11 is formed in neutral solution. Its formation constant is 1=1.12. In alkaline solution two complexes (11 and 12) are formed. Their formation constants are 1=4·105 and 2=0,2 resp.
Mit 6 Abbildungen 相似文献
11.
Yu. M. Fadeev M. I. Isaev Yu. A. Akimov P. K. Kintya M. B. Gorovits N. K. Abubakirov 《Chemistry of Natural Compounds》1988,24(1):62-65
The epigeal part of the plant ofAstragalus tragacantha Habl. (Leguminosae) has yielded, together with cyclosieversigenin 3-O--D-xylopyranoside, a new glycoside of the cycloartane series — cyclocanthoside D, the structure of which has been established on the basis of chemical transformations and spectral characteristics as 24S-cycloartane-3,6,16,24,25-pentaol 16-O--D-glucopyranoside 3-O--D-xylopyranoside.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 73–76, January–February, 1988. 相似文献
12.
Levina E. V. Kalinovskii A. I. Andriyashchenko P. V. Stonik V. A. Dmitrenok P. S. 《Russian Chemical Bulletin》2002,51(12):2295-2298
A new polyhydroxylated steroid (20R,24S)-5-cholestane-3,6,15,24-tetraol and a known glycoside, laeviuscoloside G, was isolated from the Far-Eastern starfish Henricia sanguinolenta, collected in the sea of Okhotsk, and characterized. 相似文献
13.
M. Yu. Lidak I. V. Dipan R. A. Paégle Ya. P. Stradyn 《Chemistry of Heterocyclic Compounds》1972,8(5):644-648
The protolysis constants of -(1-uracilyl)propionitriles and -(1-uracilyl)propionic -amino--(1-pyrimidyl)propionic, and -amino--(1-pyrimidyl)butyric acids (willardiine analogs) were determined. The electronic effect of substituents and of transannular interaction of the groups on the deprotonation constants is discussed.
-(1-Uracilyl)--alanine (willardiine) was isolated by Gmelin from the seeds of Acacia willardiana.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 708–712, May, 1972. 相似文献
14.
By the condensation of the mercury salt of benzotriazole with acetylpentosyl bromides in xylene, we have synthesized 1-benzotriazolyl-2,3, 4-tri-O-acetyl--D-ribo- and-xylopranosides, the deacetylation of which has given anomalous nucleosides- antimetabolites of nucleic metabolism: 1-benzotriazolyl--D-ribopyranoside and 1-benzotriazolyl-- D-xylopyranoside.For part IX, see [9]. 相似文献
15.
Summary The reaction of the 3-acetate of the 20-ketal of 16,17-oxido-5-pregnenol-3-one-20 with methylmagnesium iodide and subsequent hydrolysis of the reaction product yielded 16-methyl-5-pregnenediol-3 –17-one –20. 18-Nor-17-methyl-17-iso-5.11-pregnadienediol-3,16-one-20 was formed as a by-product. 相似文献
16.
A. Broersma P. L. de Bruyn J. W. Geus R. J. Stol 《Journal of Thermal Analysis and Calorimetry》1978,13(2):341-355
Simultaneous DTA and DTG curves (Mettler TA-2) have been measured for one diaspore and four different boehmites at temperatures up to 750° in a flow of dried argon. The crystallographic structures of the materials were assessed by X-ray diffraction and the degree of clustering of the elementary particles by scanning electron microscopy. To get straight base-lines a calibration curve was used to correct the DTA curves. The usefulness of the correction was established by comparison with DTA curves obtained with a Mettler TA-2000.The diaspore contained occluded water. Expulsion of the water at 300–350° brought about fragmentation of the crystals. The DTA and DTG peaks that correspond to the dehydration to alumina both lie at 560°.There is a noticeable spread in the DTA and DTG peaks for the different boehmites in the temperature range 455–530°. All the DTA peaks lie close to the corresponding DTG peaks. One of the boehmites displayed a double peak (470° and 502°). To trace the origin of the variation in peak temperature, the porous structure of the boehmite having its peak at 530° was varied by ball-milling and by dispersion into water, neither of which markedly affected the crystallographic structure and the crystallite size. Whereas ball-milling did not change the peak temperature much, dispersion into water brought about a transition from a single peak at 530° to a double peak at 450° and 490°. Prolonged storage in air led to a shift of the peaks to 480° and 520°. It is concluded that the porous structure of boehmites can profoundly affect the appearance and the temperature of their dehydration peaks.
The authors are indebted to Dr. P. F. Elbers for placing the electron microscopic facilities of the University of Utrecht at their disposal. We especially wish to acknowledge the time and energy spent by Mr. J. Pieters in the preparation of samples and the investigation with the scanning electron microscope. The assistance given by Dr. A. Duisenberg in the measurement of the line-broadening is also gratefully acknowledged. 相似文献
Zusammenfassung Simultane DTA- und DTG-Kurven (Mettler TA-2) wurden für ein Diaspor und vier verschiedene Boehmite bei Temperaturen bis zu 750° in einem Strom von getrocknetem Argon aufgenommen. Die kristallographische Struktur der Substanzen wurde mittels Röntgendiffraktion und der Anhäufungsgrad der Elementarpartikel mittels Raster-Elektronenmikroskopie bestimmt. Um gerade Grundlinien zu erhalten wurde eine Eichkurve zur Korrektur der DTA-Kurven verwendet. Die Nützlichkeit der Korrektur wurde durch Vergleiche der in einem Mettler TA-2000 Gerät erhaltenen DTA-Kurven festgestellt.Der Diaspor enthielt eingeschlossenes Wasser. Das bei 300 bis 350° erfolgte Abspalten des Wassers brachte eine Fragmentierung der Kristalle mit sich. Die DTA- und DTG-Peaks, welche der Dehydratisierung zu Aluminiumoxid entsprechen, liegen beide bei 560°.Im Temperaturbereich von 455 bis 530° läßt sich ein Verbreitern der DTA- und DTG-Peaks der verschiedenen Boehmite wahrnehmen. Einer der Boehmite zeigte einen Doppel-peak (470° und 502°). Um dem Ursprung der Änderungen der Peak-Temperaturen festzustellen wurde die poröse Struktur des Boehmits mit einem Peak bei 530° mit Hilfe einer Kugelmühle und durch Dispersion in Wasser verändert. Keine dieser Behandlungen änderte merklich die kristallographische Struktur und die Kristallgröße. Während das Vermählen in der Kugelmühle die Peak-Temperatur nicht wesentlich änderte, erbrachte die Dispergierung in Wasser einen Übergang von einem einzigen Peak bei 530° zu einem Doppelpeak bei 450 und 490°. Längeres Lagern an der Luft führte zu einer Verschiebung der Peaks nach 480° und 520°. Es wird gefolgert, daß die Porösstruktur von Boehmiten das Erscheinen und die Temperatur ihrer Dehydratisierungspeaks stark beeinflussen kann.
Résumé Les courbes ATD et TGD d'une diaspore et de quatre boehmites différentes ont été enregistrées simultanément (Mettler TA-2) jusqu'à 750°, sous circulation d'argon desséché. La structure cristallographique de ces composés a été examinée par diffraction des rayons X et le degré de compacité a été évalué par microscopie électronique à balayage. Une courbe d'étalonnage a été utilisée pour corriger les courbes ATD et obtenir des lignes de base droites. L'utilité de cette correction est démontrée en comparant avec les courbes ATD obtenues à l'aide d'un appareil Mettler-TA-2000.La diaspore contenait de l'eau d'inclusion. L'élimination de l'eau à 300–350° a entraîné la fragmentation des cristaux. Les pics ATD et TGD qui correspondent à la déshydratation en oxyde d'aluminium se trouvent tous deux à 560°.Un étalement des pics ATD et TGD est perceptible pour les différentes boehmites dans l'intervalle de température 455–530°. Tous les pics ATD sont proches des pics TGD correspondants. L'une des boehmites a donné un pic double (470 et 502°). Afin de trouver l'origine de la différence de température entre les deux pics, la structure poreuse de la boehmite dont le pic se situait à 530° a été modifiée par traitement dans un broyeur à boulets et par dispersion dans de l'eau; ni l'un ni l'autre de ces deux traitements n'influence de façon apparente la structure cristallographique et la taille des cristaux. Alors que le traitement au broyeur à boulets ne change pas beaucoup la température du pic, la dispersion dans de l'eau fait apparaitre le passage d'un pic unique à 530° à un pic double à 450 et 490°. Le stockage prolongé dans l'air provoque un déplacement des pics à 480 et 520°. On en conclut que la structure poreuse des boehmites peut influer profondément sur l'apparition et la température de leurs pics de déshydratation.
— ( TA-2) 750° . - , — . . , TA-2000. . 300–350°C, . — , , 560°. - 455–530°. . (470° 502°). , 530°C . . , — 530° — 450° 490°. 480° 520°. , , .
The authors are indebted to Dr. P. F. Elbers for placing the electron microscopic facilities of the University of Utrecht at their disposal. We especially wish to acknowledge the time and energy spent by Mr. J. Pieters in the preparation of samples and the investigation with the scanning electron microscope. The assistance given by Dr. A. Duisenberg in the measurement of the line-broadening is also gratefully acknowledged. 相似文献
17.
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
18.
Conclusions The triterpene glycosides scabiosides D, E, F, and G have been isolated from the roots ofPatrinia scabiosofolia Fisch. et Link. It has been established that scabioside D is O--D-glucopyranosyl-(1 4)-O--L-arabopyranosyl-(1 3)-O-oleanoloyl-(28 1)--D-xylopyranose, and scabioside E is O--D-glucopyranosyl-(1 4)-O--L-arabopyranosyl-(1 3)-O-oleanoloyl-(28 1)-O--D-xylopyranosyl-(4 1)--L-rhamnopyranose. 相似文献
19.
Tetsumi Irie Masaki Otagiri Kaneto Uekama Yoshiro Okano Takeshi Miyata 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(3-4):637-644
From the gross and histological examinations, -cyclodextrin (-CyD) was found to reduce the muscular tissue damage produced by chlorpromazine hydrochloride (CPZ) onM. vastus lateralis in rabbits. The protective effect of -CyD may be attributable to the decrease in affinity of CPZ to the tissue membrane through inclusion complexation. There was no appreciable difference in the pharmacokinetic and pharmacodynamic behaviors between CPZ and its -CyD complex in rabbits. These results suggest that -CyD is useful to reduce the local tissue toxicity of CPZ without altering the pharmacological efficacy. 相似文献
20.
In contrast to -propiolactone and diketene, -trichloromethyl--propiolactone generally reacts with -amino heterocyclic nitrogen compounds to give amides of 3-hydroxy-4,4,4-trichlorobutyric acid (with the participation of the exocyclic and endocyclic nitrogen atoms of the reagents) rather than condensed heterocycles (pyrimidine derivatives). The reasons for the difference in the reactivities of the indicated -lactones are discussed.See [1] for communication XIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 260–265, February, 1972. 相似文献