Investigation of structural features of the Y3Al5O12: Ce3+/Lu2O3 crystal phosphors formed by the colloidal chemical method

The specific features of the crystal structure of crystal phosphors Y₃Al₅O₁₂: Ce³⁺/Lu₂O₃ (Lu₂O₃: Ce) synthesized by the colloidal chemical method have been investigated by neutron diffraction at room temperature. The influence of the method used for introducing Lu₂O₃ into the system on the structure and luminescence properties of the samples has been analyzed. The investigation has revealed that the spectra of the samples prepared under the most nonequilibrium conditions are characterized by the Stokes shift and high photoluminescence intensity. This has been explained by the disorder of their crystal structure due to the formation of stable associates of defects.     

A study of the reaction of pentacyclic triterpenoids with concentrated sulfuric acid

Summary The conditions for the reaction of triterpenoids with concentrated sulfuric acid have been studied by the method of mathematical planning, and the optimum conditions for performing this reaction have been found.Pyatigorsk Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 294–296, May–June, 1971.     

Triterpene glycosides of the leaves of Eleutherococcus senticosus II. Structure of eleutherosides I, K, L, and M

Summary The complete structures of eleutherosides I, K, L, and M have been established. Glycoside I is identical with mubenin B and glycoside M with hederasaponin B. It has been shown that eleutheroside K is the 3-[O--L-rhamnopyranosyl-(1»2)--L-arabopyranoside] of oleanolic acid. In eleutheroside L, the L-rhamnose and L-arabinose residues are connected by a 1»4 bond, and a trisaccharide consisting of O--L-rhamnopyranosyl-(1»4)-O--D-glucopyranosyl-(1»6)--D-glucopyranose is connected with the carboxy group.Institute of Biologically Active Substances of the Far-Eastern Scientific Center of the Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 618–622, September–October, 1971.     

Reaction of 3-cyanopyridine-2(1H)-thiones with N-butyllithium

The reaction of 3-cyanopyridine-2(1 H)-thiones with BuLi in ether was studied. It was found that the metallation proceeds initially at the sulfur atom. The resulting lithium salts add a second equivalent of n-butyllithium at the CN group. The hydrolysis of the dilithium derivatives leads to 3 pentanoylpyridine-2(IH)-thiones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 231–234, February, 1996.     

Orientation in the nitration of 3-phenyl-4-substituted furazans

The nitration of 3-phenyl-4-substituted furazans with various nitrating agents was investigated. It is shown that the orientation of the nitro group that is incorporated in the phenyl ring is determined by the substituent in the 4 position of the furazan ring, whereas the introduction of a furazan substituent in the phenyl ring lowers the reactivity of the latter. The corresponding dinitro derivatives can be obtained by means of acid mixtures.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 27–29, January, 1982.     

New unsymmetrical salen-type ligand from enantiomerically pure 2-hydroxypinan-3-one

The reaction of enantiomerically pure (–)-2-hydroxypinan-3-one with ethylenediamine was studied. Depending on the reagent ratio, the reaction can afford either mono- or bis-Schiff"s bases. The enantiomerically pure unsymmetrical terpenoid salen-type ligand was prepared by the reaction of 3-[(2-aminoethyl)imino]pinan-2-ol with salicylaldehyde.