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1.
Attempted dephthaloylation 4-methyl-3-phthalimido- of 1-(p-methoxyphenyl)-4-(2-oxo-4thiazolin-4-yl)azetidin-2-one with methylhydrazine resulted in a ring transformation to give a fused thiazolo[3,4-a]pyrazine derivativeDepartment of Organic Chemistry, Technical University Budapest, H-1521 Budapest, Hungary. Central Research Institute for Chemistry of the Hungarian Academy of Sciences, H-1525 Budapest, Hungary. Published in Khimiya Geterotsiklichesicikh Soedinenii, No. 10, pp. 1405–1408, October, 1995. Original article submitted June 15, 1995.  相似文献   

2.
Acetates of the brassinosteroids 28-homotyphasterol and (22S,23S)-28-homotyphasterol have been obtained from stigmasterol. The scheme of synthesis includes the epoxidation of the corresponding 2,22-diene-6-ketone, reduction of the 2, 3:22,23-diepoxy-6-ketone formed with lithium tetrahydroaluminate to a 22,23-epoxy-3,6-diol, oxidation of the 6-hydroxy group to a 6-ketone, and conversion of the 22,23-epoxides into cis-22,23-diols.Institute of Bioorganic Chemistry, Belarus Academy of Sciences, 220141, Minsk, ul. Zhodinskaya, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 694–699, September–October, 1995. Original article submitted January 30, 1995.  相似文献   

3.
The dehydration of hydrated calcium and strontium bromides and iodides was studied by thermogravimetry and differential thermal analysis. The melting in the crystallization water was distinguished from the dehydration in a self-generated atmosphere. The results of the TG and DTA curves made simultaneously were verified by measurements with a Du Pont DSC apparatus. This latter investigation was extended to the previously studied chlorides too. Correlations were found between the temperature of melting or of dehydration and the ionic radii of the respective cations and anions.
Zusammenfassung Die Dehydratisierung von Calcium- und Strontium-Bromid- und Jodidhydraten wurde mit den Methoden der Thermogravimetrie und Differentialthermoanalyse verfolgt. Das Schmelzen im Kristallwasser wurde von der Dehydratisierung in der selbsterzeugten Atmosphäre getrennt. Die Ergebnisse der simultan erhaltenen TG- und DTA-Kurven wurden durch Messungen mit einem Du Pont DSC-Gerät bestätigt, wobei die bereits schon untersuchten Chloride mit einbezogen wurden. Korrelationen zwischen den Schmelzoder Dehydratisierungstemperaturen und den Ionenradien der entsprechenden Kationen und Anionen werden beschrieben.

Résumé Etude de la déshydratation des bromures et iodures de calcium et de Strontium hydratés par thermogravimétrie et par analyse thermique différentielle. La fusion dans l'eau de cristallisation a été distinguée de la déshydratation en atmosphère auto-générée. Les résultats des courbes TG et ATD obtenues simultanément ont été vérifiés par des mesures effectuées à l'aide d'un analyseur calorimétrique différentiel (DSC) Du Pont. L'étude a également été étendue aux chlorures précédemment étudiés. On propose des corrélations entre les températures de fusion ou de déshydratation et les rayons ioniques des cations et anions respectifs.

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4.
A new direction of the reaction of pennogenin diacetate with BF3·Et2O has been discovered in which a previously unknown dimeric steroid is formed — (25R,22R,25R)-3,3-diacetoxy-26,22-epoxy-16,16-bifurosta-5,20(22), 5,17(20)-tetraen-26-ol, the structure of which has been established as the result of an analysis of IR, UV,1H and13C NMR, and mass spectra. A probable mechanism for the formation of the title compound from pennogenin diacetate is suggested.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Institute of Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 202–208, March–April, 1990.  相似文献   

5.
Methods for the synthesis of 2,4-dithioxo-6,6-dimethyl-5,6-dihydro-8H-pyrano(thiopyrano)[4,34,5]thieno[2,3-d]pyrimidines have been developed.For Communication 10 see [1].A. L. Mndzhoyan Institute of Technical Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan 375014. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 803–804, June, 1998.  相似文献   

6.
The epigeal part ofThalictrum minus L. has yielded a new bidesmoside — thalicoside B — which has the structure of oleanolic acid 28-O--D-glucopyranoside 3-O-[O--L-rhamnopyranosyl-(1 2)-O--D-glucopyranosyl-(1 3)--L-arabinopyranoside].Irkutsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR; A. A. Zhdanov Irkutsk State University; and Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 670–676, September–October, 1985.  相似文献   

7.
Thalicoside D — a new triterpene glycoside isolated fromThalictrum minus L. (Ranunculaceae) — has the structure of oleanolic acid 3-O-[O--L-rhamnopyranosyl-(12)-O--D-glucopyranosyl-(14)--L-arabinopyranoside 28-O-[O--D-glucopyranosyl-(16)--D-glucopyranoside]. This structure was established by the use of the results of acid and alkaline hydrolyses, SIMS spectra, and one- and two-dimensional NMR spectroscopy.Deceased.Irkutsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan [IKhRV AN RUz], Tashkent, FAX (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 398–403, May–June, 1994.  相似文献   

8.
The first representatives of pyrazolines were synthesized in the last century. These nitrogen-containing heterocyclic compounds became important in the development of different bioactive substances. For this reason, various procedures have been worked out for their synthesis. In the present article we summarize those synthetic methods providing 1- or 2-pyrazolines by the reactions of ,-unsaturated ketones with diazomethane or hydrazine derivatives.Department of Organic Chemistry, Kossuth Lajos University, Egyetem ter I, H 4010 Debrecen, Hungary. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 747–759, June, 1997.  相似文献   

9.
Zusammenfassung Der induktive Effekt einer an ein aromatisches oder konjugiertes System gebundenen GruppeG wird durch die Änderung desCoulombintegrals desjenigen C-Atoms, an das die GruppeG direkt gebunden ist, berücksichtigt, indem für dieses s = + angesetzt wird. Der den induktiven Effekt quantitativ beschreibende Parameter kann aus UV-Spektren abgeleitet werden. Die Prozedur dieser halbempirischen Bestimmung von wird allgemein beschrieben und begründet.Mit 1 AbbildungDie wesentlichen Teile dieser Arbeit wurden während meiner Zugehörigkeit zur Quantum Chemistry Group des Mathematical Institute, University of Oxford, im Studienjahr 1957/58 ausgeführt. Vgl. Progress Report, Session 1957–1958, S. 26.  相似文献   

10.
    
Ohne ZusammenfassungEine Zusammenfassung der früheren Arbeiten befindet sich in O. Samuelson, Ion Exchangers in Analytical Chemistry, Stockholm: Almqvist & Wiksell, 1952, und New York: Wiley & Sons, 1953.Wir danken Statens Tekniska Forskningsråd für die Bereitstellung von Mitteln.  相似文献   

11.
The synthesis of 20-deoxy compounds — the precursors of the steroid pyranols and pyranones synthesized by the authors previously — has been effected from a steroid 20-ketotetrahydropyran by the hydrogenolysis of the corresponding ethylene dithioketal with Raney nickel. The1H and13C NMR spectra have been studied in detail. Transformations of rings A and B via the epoxide or the 3,5-cyclosteroid have led to 3-acetoxy-16,23-epoxy-5H-21,24-dinorchol-5-en-6-one and 3-acetoxy-5-hydroxy-16,23-epoxy-21,24-dinorchol-5-en-6-one.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 732–735, November–December, 1983.  相似文献   

12.
It has been shown that the polymerization of colchicidyl-L-lysine N-carboxyhydride under the action of amines obeys the general laws of the occurrence of anionic polymerization and is described, when primary amines are used, by a mechanism of normal amine addition and, when tertiary amines are used by the activated monomer mechanism.V. I. Lenin Tashkent State University. Institute of Organic Chemistry and Institute of Organic Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 848–850, November–December, 1988.  相似文献   

13.
Summary An analysis of the present situation of Analytical Chemistry is performed, taking into consideration the difference to be observed between the large and further increasing importance of Analytical Chemistry in industrial research, development and quality control and the poor reputation of the subject at many universities. The main reason for the latter can be located in the existence of outdated curricula for Analytical Chemistry. Many chairs or departments of Analytical Chemistry leave the education in modern physical methods for separation and identification as well as Computer Based Analytical Chemistry (COBAC) and its applications to life-, environmental- and material sciences to other departments and restrict themselves to classical subjects. According to a survey of the Working Party on Analytical Chemistry of the Federation of European Chemical Societes (Chairman: Prof. Dr. E. Pungor) this holds true especially for universities without an own chair or department of Analytical Chemistry. Modern Analytical Chemistry, however, is definitively no longer an appendix of any other subject but the interdisciplinary science of the generation of information about the composition and the structure of matter. Furthermore Analytical Chemistry is the key to solve problems related to material systems. It is the — certainly difficult but fascinating — task of the professor of Analytical Chemistry to present together with his team the complex modern curricula (chemical analysis, biochemical analysis, chemometrics, analytical strategies, material analysis, clinical analysis, environmental analysis etc.) according to the principle of the reduction to the scientific basis.Students should be able to read and understand the present literature but must be able to deal with future developments as well. Such a presentation of the basic principles of the methods of Analytical Chemistry is superior to any phenomenological way. The idea of an intellectual School of Analytical Chemistry with a coordinated distribution of duties has turned out to be very successful in the realization of this ambitious teaching concept. Based on these and further thoughts an ideal model curriculum for Analytical Chemistry at Technical Universities is presented and compared with actual situations.
Strategie der Lehre und Modellehrplan für das Studium der modernen analytischen Chemie
Zusammenfassung Ausgehend vom derzeit immer noch zu beobachtenden Gegensatz zwischen der großen und weiter steigenden Bedeutung der Analytischen Chemie in industrieller Forschung, Entwicklung und Qualitätskontrolle und der geringen Reputation dieses Faches an vielen Universitäten wird eine Analyse der Ursachen dieser Situation und der möglichen Entwicklung vorgenommen. Als Hauptursache wurde gefunden, daß die meisten Universitätslehrpläne für Analytische Chemie veraltet sind. Sie überlassen die Erziehung in den modernen physikalischen Trenn- und Bestimmungsverfahren und der COBAC (Computer Based Analytical Chemistry) sowie deren Anwendung auf Lebensmittel-, Umwelt-, Werkstoffkontrolle usw. anderen Abteilungen und beschränken sich auf die Vermittlung überwiegend klassischer Lehrinhalte. Nach einer 1983 durchgeführten Studie der Working Party on Analytical Chemistry der Federation of European Chemical Societies (Chairman: Prof. Dr. E. Pungor) trifft dies besonders für Universitäten zu, die keinen eigenen Lehrstuhl oder Bereich für Analytische Chemie aufweisen. Moderne Analytische Chemie ist jedoch endgültig kein Anhängsel irgendeines anderen Faches mehr, sondern die fachübergreifende Wissenschaft von der Erzeugung von Information über die Zusammensetzung und Struktur von Materie. Darüber hinaus ist sie der Schlüssel zur Problemlösung in materiellen Systemen. Es ist die — sicher schwierige aber reizvolle — Aufgabe des Professors für Analytische Chemie, gemeinsam mit seinem Team die modernen komplexen Lehrinhalte (Chemische Analyse, Physikalische Analyse, Biochemische Analyse, Chemometrie, Analysenstrategie, Werkstoffanalyse, klinische Analyse, Umweltanalytik usw.) nach dem Prinzip der Reduktion auf ihre wissenschaftlichen Grundlagen zu präsentieren, so daß die Studenten die derzeitige Literatur lesen können, aber auch für zukünftige Entwicklungen offen sind. Eine solche die Zusammenhänge betonende Präsentation der Grundlagen chemischer und physikalischer Methoden der Analytischen Chemie ist einer phänomenologischen Darstellung weit überlegen. Zur Realisierung dieses ehrgeizigen Lehrkonzeptes zur Erziehung eines kritikfähigen Analytischen Chemikers erweist sich die Form der geistigen Schule der Analytischen Chemie mit deren koordinierter Aufgabenteilung als sehr erfolgreich. Auf der Basis dieser und weiterer Überlegungen wird ein idealer Modellehrplan für Analytische Chemie an Technischen Universitäten präsentiert und mit gegenwärtigen Gegebenheiten verglichen.


Because of the fact that this paper — heavily discussed at the symposium New Trends in Chemistry — The Role of Analytical Chemistry in National Development, Cairo, January 3–7, 1984, has got a tremendous interest we feel it should be presented also to the readers of this journal in order to further stimulate the discussion  相似文献   

14.
A new triterpene glycoside has been isolated from the roots ofMedicago sativa L. (family Fabaceae) — medicoside J, and its structure has been established as a medicagenic acid 3-O--D-glucopyranoside 28-O-[O--D-xylopyranosyl-(1 4)-O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside].Institute of the Chemistry of Plant Substances of the Uzbek Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 610–613, September–December, 1986.  相似文献   

15.
The structure of a new cycloartane glycoside, cycloaraloside B, isolated from the roots ofAstragalus amarus Pall. (Leguminosae) has been established on the basis of chemical transformations and spectral characteristics: it is 20R,24S-epoxycycloartane-3,6,16,25-tetraol 3-O-[O--L-rhamnopyranosyl-(12)-(6-O-acetyl--D-glucopyranoside)].Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 528–531, September–October, 1992.  相似文献   

16.
The reaction of 3,4-diaminofurazane and 4,4-diamino-3,3-difurazanyl with dimethyl sulfide ditriflate provided the first syntheses for 3,4-bis(dimethylsulfilimino)furazane and 4,4-bis(dimethylsulfilimino)-3,3-difurazanyl.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1922–1923, August, 1992.  相似文献   

17.
Aspen wood biolignins have been investigated by IR spectroscopy and -, procedure has been developed for determining the amounts of -, ß- and -carbonyl groups in the lignins obtained from aspen wood after the action of the lignin-destroying fungusPhanerochaete sanguinea. A large contribution of the C-oxidation reaction and the appearance in the biolignins of ester groups and also nonconjugated ketone and aldehyde groups have been revealed. The latter may, presumably, be -, consequence of the oxidation of the C atoms of the propane chain and the appearance of -O-4 structural units in the lignin.Institute of Organic Chemistry, Siberian Division of the Russian Academy of Sciences, Irkutsk, fax (3952) 46 03 31. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 474–478, May–June, 1995. Original article submitted July 25, 1994.  相似文献   

18.
In reaction with amines 2-methyl-2-(1-halogenoalkyl)-3(2H) furanones form S-amino-1-halogeno-3-hydroxy-2-methyl-4 penten-3-ones and 6-amino-2-halogeno-3-hydroxy-3-methyl-5-hexen-3-ones, which are converted by the action of bases into the corresponding oxiranyl -aminovinyl ketones.Belorussian State University, Department of Organic Chemistry and Chemistry of High-Molecular Compounds, Minsk. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 609-612, May, 1995. Original article submitted April 11, 1995.  相似文献   

19.
New derivatives of pyrano[3,45,6]pyrido[2,3-d]pyrimidines were synthesized from ethyl 2-amino-7,7-dimethyl-7,8-dihydro-5H-pyrano[4,3-b]pyridine-3-carboxylate.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1239–1241, September, 1999.  相似文献   

20.
The semiempirical MINDO-3, MPDP, and AM-1 methods are shown to be applicable to the calculation of the cyclization of 1-oxa-and 1-azabutadienylketenes. The mechanisms of the heterocyclizations have been studied. Formation of the new -bond results from interaction of the unshared electron pair of the heteroatom with the x * of the ketene C=O bond.Ural State Technical University, Ekaterinsburg 620002. Physical and Organic Chemistry Research Institute, Rostov State University, Rostov-on-Don 344711. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 113–120, January, 1997.  相似文献   

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