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11.
Victoria V. Lipson Irina V. Ignatenko Sergey M. Desenko Svetlana V. Shishkina Oleg V. Shishkin Sergey A. Komykhov Natalya V. Logvinenko Valery D. Orlov Herbert Meier 《Journal of heterocyclic chemistry》2003,40(6):1081-1086
The reaction of 5,7‐diphenyl‐4,7‐dihydro‐1,2,4‐triazolo[1,5‐a]pyrimidine ( 1 ) with α,β‐unsaturated carbonyl compounds 2a‐f led to the formation of the alkylated heterocycles 3a‐f (Figure 1). However, the reaction of 5‐methyl‐7‐phenyl‐4,7‐dihydro‐1,2,4‐triazolo[1,5‐a]pyrimidine ( 5 ) with 2a‐c yielded under the same conditions the triazolo[5,1‐b]quinazolines 6a‐c (Figure 3). In this case, the alkylation is followed by a cyclocondensation. The structure elucidation of the products is based on ir, ms, 1H and 13C nmr measurements and on an X‐ray diffraction study. 相似文献
12.
I. V. Ukrainets L. V. Sidorenko O. V. Gorokhova S. V. Shishkina 《Chemistry of Heterocyclic Compounds》2006,42(6):776-781
Alkaline hydrolysis of the ethyl ester of 4-(cyanoethoxycarbonylmethyl)-2-oxo-1,2-dihydroquinoline-3-carboxylic acid is accompanied
by decarboxylation with loss of two molecules of CO2 and leads to 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 887–893, June, 2006. 相似文献
13.
I. V. Ukrainets N. L. Bereznyakova O. V. Gorokhova A. V. Turov S. V. Shishkina 《Chemistry of Heterocyclic Compounds》2007,43(8):1001-1007
The hydrogenation of the benzene part of the molecule in N-allyl-substituted 4-hydroxy-2-quinolinones does not affect the
nature of their bromination by molecular bromine and gives 2-bromomethyl-5-oxo-1,2,6,7,8,9-hexahydro-5H-oxazolo[3,2-a]quinolines.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1180–1188, August, 2007. 相似文献
14.
The behaviour of gold and elements impeding its x-ray fluorescence spectrometric (XRF) determination, namely zinc, lead and arsenic, was studied during their extraction from hydrochloric acid, nitric acid, and aqua regia solutions using tributyl phosphate as a solid extractant [SE(TBP)]. Extraction of gold from pulps after aqua regia leaching was found to be the most favourable approach for the quantitative and selective recovery of gold. The gold distribution ratio, DAu, is ca. 104 ml g?1. For extraction from hydrochloric acid solutions the DAu value also exceeds 104 in the whole range of gold concentrations studied (10?8?10?4 M), but it decreases substantially with increasing extraction temperature, from 5 × 105 ml g?1 at 20°C to 9 × 103 ml g?1 at 70°C. An anomalously high distribution ratio of lead, DPb ≈ 103 ml g?1, was observed during extraction from hydrochloric solutions in the presence of chlorine. This could be explained by the formation of the chloro complexes of lead(IV). An XRF method for the determination of gold in natural samples was developed, which includes back-extraction of gold from SE(TBP) using a hot 0.025 M thiourea solution, providing a thin sample layer for secondary XRF. For 25 g of sample material the limit of determination is 10 ng g?1 (10?6%). The accuracy of the technique was checked using different reference materials. The results agreed within 10%. 相似文献
15.
Svitlana V. Shishkina Irina S. Konovalova Pavlo V. Trostianko Anna O. Geleverya Sergiy M. Kovalenko Natalya D. Bunyatyan 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(6):822-832
The polymorphic study of 3‐(3‐phenyl‐1H‐1,2,4‐triazol‐5‐yl)‐2H‐1‐benzopyran‐2‐one, C17H11N3O2, was performed due to its potential biological activity and revealed three polymorphic modifications in the triclinic space group P, the monoclinic space group P21 and the orthorhombic space group Pbca. These polymorphs have a one‐column layered type of crystal organization. The strongest interactions between the molecules of the studied structures is stacking between π‐systems, while N—H…N and C—H…O hydrogen bonds link stacked columns forming layers as a secondary basic structural motif. C—H…π hydrogen bonds were observed between neighbouring layers and their role is the least significant in the formation of the crystal structure. Packing differences between the polymorphic modifications are minor and can be identified only using an analysis based on a comparison of the pairwise interaction energies. 相似文献
16.
V. N. Berezhnaya V. P. Vetchinov R. P. Shishkina V. I. Mamatyuk 《Russian Chemical Bulletin》1993,42(2):318-322
Using1H and13C NMR spectroscopy, naphthodihydroimidazolediols were identified as the primary products of photolysis of 2-dialkylamino-3-amino(alkylamino)-1,4-naphthoquinones. Their further non-photochemical (thermal) transformations depend on their structure and on the photolysis conditions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 358–362, February, 1993. 相似文献
17.
18.
Mazaletskaya L. I. Sheludchenko N. I. Kozlov M. V. Shishkina L. N. 《Russian Chemical Bulletin》2019,68(10):1919-1923
Russian Chemical Bulletin - An inhibition by the semisynthetic polyphenols bearing bicyclic isobornyl substituents and OH groups arranged variously relative to each other was investigated in the... 相似文献
19.
Shishkina Svitlana V. Ishchenko Alexander A. Kulinich Andrii V. 《Structural chemistry》2021,32(3):1341-1345
Structural Chemistry - Herein we report an X-ray crystallographic characterization of tetramethine merocyanine based on benzimidazole and thiobarbituric acid, which shows negative solvatochromism... 相似文献
20.
Yana I. Sakhno Svetlana V. Shishkina Oleg V. Shishkin Vladimir I. Musatov Elena V. Vashchenko Sergey M. Desenko Valentin A. Chebanov 《Molecular diversity》2010,14(3):523-531
Heterocyclization reactions of pyruvic acids, aromatic aldehydes and 5-amino-N-aryl-1H-pyrazole-4-carboxamides yielding four different types of final compounds are described. The reactions involving arylidenpyruvic
acids lead with high degree of selectivity to either 4,7-dihydropyrazolo[1,5-a]pyrimidine-5-carboxylic acids or 5-[(2-oxo-2,5-dihydrofuran-3-yl)amino]-1H-pyrazoles, depending on the catalyst type or temperature regime. The interactions based on arylpyruvic acids can take place
under kinetic or thermodynamic control producing 7-hydroxy-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-7-carboxylic acids or 3-hydroxy-1-(1H-pyrazol-5-yl)-1,5-dihydro-2H-pyrrol-2-ones, respectively. 相似文献