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1.
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]. 相似文献
2.
B. I. Popov L. L. Sedova G. N. Kustova L. M. Plyasova Yu. V. Maksimov A. I. Matveev 《Reaction Kinetics and Catalysis Letters》1976,5(1):43-49
In the study of the Fe1–xCrxMo1·5O6 system by X-ray, IR and Mössbauer methods the formation of solid state substitution solutions has been detected, which possess similar catalytic properties in methanol oxidation.
, , Fe1–xMo1·5O6 , .相似文献
3.
T. V. Rybalova V. F. Sedova Yu. V. Gatilov O. P. Shkurko 《Chemistry of Heterocyclic Compounds》1998,34(10):1161-1165
The crystal structure of 2-nitropyridine has been determined by x-ray diffraction analysis. The influence of the nitro group
on the geometric parameters of the molecule was evaluated, as well as its influence on the molecular parameters of other nitropyridines,
depending on the position of this group in the pyridine ring.
Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090. E-mail:
gatilov@nioch.nsc.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1371, October, 1998. 相似文献
4.
Phenyl(methyl)-substituted 2- and 4-nitroso- and azoxypyrimidines were synthesized for the first time by the oxidation of phenyl(methyl)-substituted 2- and 4-hydroxy-aminopyrimidines by activated MnO2, Ag2CO3 on zeolite, or BaMnO4. Certain chemical properties of the synthesized nitrosopyrimidines were studied, such as reduction, nucleophilic substitution of the nitroso group, the condensation reaction with aniline and hydroxyaminopyrimidines.For Preliminary communication, see [1].DeceasedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 962–968, July, 1989. 相似文献
5.
6.
We study the stability of the zero solution to a nonlinear system of ordinary differential equations on the base of its Takagi–Sugeno (TS) representation. As is known, the most constructive stability and stabilization conditions for TS systems stated as linear matrix inequalities are established with the help of a general quadratic Lyapunov function (GQLF). However, such conditions are often too rigid. Using a modification of the Lyapunov direct method, we propose asymptotic stability conditions with weaker requirements to GQLF. They allow an application to a wider class of systems. We also give some illustrative examples. 相似文献
7.
Yulia Shulpekova Vladimir Nechaev Svetlana Kardasheva Alla Sedova Anastasia Kurbatova Elena Bueverova Arthur Kopylov Kristina Malsagova Jabulani Clement Dlamini Vladimir Ivashkin 《Molecules (Basel, Switzerland)》2021,26(12)
Folates have a pterine core structure and high metabolic activity due to their ability to accept electrons and react with O-, S-, N-, C-bounds. Folates play a role as cofactors in essential one-carbon pathways donating methyl-groups to choline phospholipids, creatine, epinephrine, DNA. Compounds similar to folates are ubiquitous and have been found in different animals, plants, and microorganisms. Folates enter the body from the diet and are also synthesized by intestinal bacteria with consequent adsorption from the colon. Three types of folate and antifolate cellular transporters have been found, differing in tissue localization, substrate affinity, type of transferring, and optimal pH for function. Laboratory criteria of folate deficiency are accepted by WHO. Severe folate deficiencies, manifesting in early life, are seen in hereditary folate malabsorption and cerebral folate deficiency. Acquired folate deficiency is quite common and is associated with poor diet and malabsorption, alcohol consumption, obesity, and kidney failure. Given the observational data that folates have a protective effect against neural tube defects, ischemic events, and cancer, food folic acid fortification was introduced in many countries. However, high physiological folate concentrations and folate overload may increase the risk of impaired brain development in embryogenesis and possess a growth advantage for precancerous altered cells. 相似文献
8.
M. M. Zverev V. O. Val’dner N. A. Gamov R. V. Esin S. I. Gronin E. V. Zhdanova S. V. Ivanov P. S. Kop’ev D. V. Peregoudov I. V. Sedova S. V. Sorokin V. B. Studionov 《Optics and Spectroscopy》2011,111(2):178-181
The fracture patterns of active elements of pulsed green lasers with transverse electron-beam pumping, based on ZnSe-containing quantum-size structures, have been investigated. The fracture in the form of thin (~1 μm) and long (to 100–150 μm) filaments can be explained by the self-focusing of the intrinsic laser radiation in the semiconductor structure. 相似文献
9.
A. V. Agaponova E. E. Shalygina O. N. Tarakanov I. V. Bykov S. A. Maklakov A. A. Pukhov I. A. Ryzhikov M. V. Sedova I. T. Yakubov 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(2):184-186
The results from magnetooptical studies of the influence of magnetochemical effects on the surface morphology and local magnetic
properties of FeN alloy thin films and thin-film systems that consist of alternating silicon dioxide and FeN layers of submicron
thickness, are shown. The dramatic influence of chemical etching on the surface morphology and magnetic characteristics of
the investigated samples is revealed. 相似文献
10.
Baranov P. G. Romanov N. G. Tolmachev D. O. Babunts R. A. Namozov B. R. Kusrayev Yu. G. Sedova I. V. Sorokin S. V. Ivanov S. V. 《JETP Letters》2008,88(9):631-635
JETP Letters - The axial fine structure with strong positive zero-field splitting for Mn2+ ions in CdMnSe/ZnSe quantum dots caused by their low dimensionality was revealed. Magnetic resonance was... 相似文献