Pyrimidines

The reaction of cyclohexanone with arylidenebisureas (e.g. benzal-bisurea) in an acid medium has given 4, 4-diaryl-2, 2-dioxo-5, 5-trimethylene-6, 6-spirobishexahydropyrimidines (II). The acid hydrolysis of IIa (aryl-C₆H₅) in the presence of 2, 4-dinitrophenylhydrazine leads to the 2, 4-dinitrophenylhydrazone of 2-hydroxy-8-oxo-4-phenyl-5, 6, 7, 8-tetrahydroquinazoline (IV). Compound IV was also obtained by the ozonization of 2-acetoxy-8-benzal-4-phenyl-5, 6, 7, 8-tetrahydroquinazoline (IX) and subsequent decomposition of the ozonide with a solution of 2, 4-dinitrophenylhydrazine. The structure of the compounds obtained was confirmed by means of their IR, UV, and PMR spectra. Corresponding 6, 6-spirobishexahydropyrimidines have also been obtained from 2-methylcyclohexanone, acetone, and methyl ethyl ketone and benzalbisurea.For part XIV, see [1].     

Structure of polymers obtained from sulfur monochloride and olefins containing sulfonium salt structures

Reactions of sulfur monochloride with diolefins lead to polymeric products which can be reduced to diepisulfides in low yield. In reactions with cyclic triolefins, polymers containing tricyclic sulfonium structures are obtained as a results of transannular additions and subsequent transannular displacements. Due to the insolubility and reactivity of these ionic structures, only incomplete structural assignements could be made, but the reactions are studied on similar cyclic structures which provide model systems.     

The vinylation of benzotriazole

The reaction of benzotriazole with acetylene under pressure in the presence of potassium hydroxide and cuprous chloride has been examined. 1-Vinylbenzotriazole was obtained in 75% yield.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1289–1290, September, 1970.     

Structure of convosine

From the roots of the plantConvolvulus subhirsutum Regel et Schmalh. have been isolated seven known alkaloids and one new one, for which, on the basis of spectral characteristics, a comparative study with known alkaloids of the tropane series, and synthesis, the structure of (+)-N-isopropyl-3-veratroyloxynortropane has been established.Institute of the Chemistry of Plant Substances of the Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 618–620, September–October, 1986.     

Über Spurenelementbestimmungen in Leberproben Mittels Protoneninduzierter Röntgenfluoreszenz (Pixe)

Multi-element-analysis by PIXE in respect to medical applications is discussed. Examples of trace-element determinations in liver tissues are given, demonstrating the applicability and usefulness of this rather new analytical technique.      

Oxydation photochimique d'amines tertiaires et d'alcaloideS—IX: Oxydation photochimique d'alcaloides quinolizidiniques et indolizidiniques tetracycliques: sparteine et α-isosparteine,lupanine et α-isolupanine,camoensidine et tetrahydroleontidine

The influence of ring size and ring conformation on the site of photosensitized oxidation of tertiary amines was illustrated by the photooxidation of tetracyclic indolizidine and quinolizidine alkaloids. An amino radical intermediate has been supposed during photooxidation of lupanine sensitized by eosin under nitrogen atmosphere.     

Investigation of the interaction between zinc oxide and phosgene

It has been shown that in the interaction of zinc oxide and phosgene, the most active are the samples having oxygen vacancies. A mechanism for this process is suggested.

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ESR spectra of AsF2−6 and SbF2−6

ESR spectra observed in γ-irradiated CsAsF₆ and CsSbF₆ matrices have been assigned to the free radicals AsF^2?₆ and SbF^2?₆ respectively. The large, isotropic central-atom hyperfine interactions and isotropic g-values of these species suggest that they possess ²A_tg ground-states in O_h symmetry. The contribution to the semi-occupied orbital of the central-atom valence s atomic orbital is ≈ 0.6, greater than in the halogen hexafluorides (≈0.4) and the chalcogen hexafluoride anions (≈ 0.5). Variation of the central-atom hyperfine interaction with temperature is interpreted in terms of a second-order Jahn-Teller effect involving a low-lying ²T_1u excited state.     

Electron-impact fragmentation of penta-fluorophenyldimethylsilyl ethers of some sterols of biological importance

The mass spectral properties under medium and high resolution of a new protecting group for sterols is described and its ability to direct fragmentation is compared with established derivatives. The mass spectra obtained are characterised by strong molecular ions which fragment to produce a more even ion distribution than the familiar TMS ethers. This results in enhanced abundance of hydrocarbon fragments, with molecular structural details given greater prominence than is found with other derivatives.     

Anhand der Methode der Konfigurationenwechselwirkung berechnete Dipolmomente einiger nichtalternierender Kohlenwasserstoffe in angeregtem Singulett- und Triplettzustand

Ohne ZusammenfassungDie Verfasser erachten es für ihre angenehme Pflicht, an dieser Stelle Frl. N. Grozdanova für ihre Hilfe bei der Zusammenstellung des Programms für die Elektronenrechenmaschine den verbindlichsten Dank auszusprechen.