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71.
K. Yu. Chegaev A. N. Kravchenko O. V. Lebedev Yu. A. Strelenko P. A. Belyakov 《Chemistry of Heterocyclic Compounds》2002,38(10):1250-1252
N-Trimethylsilyl derivatives of 2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones have been prepared for the first time and the electrophilic substitution reaction of the trimethylsilyl group has been studied. 相似文献
72.
Mohammad Ali Zolfigol Davood Azarifar Iraj Mohammadpoor-Baltork Behrooz Maleki 《Tetrahedron letters》2006,47(5):833-836
4-(p-Chloro)phenyl-1,3,4-triazole-3,5-dione is used as an effective oxidizing agent for the oxidation of 1,3,5-trisubstituted pyrazolines to their corresponding pyrazoles under mild conditions with moderate to good yields at room temperature. 相似文献
73.
S. M. Ramsh A. G. Ivanenko V. A. Shpilevyi N. L. Medvedskiy P. M. Kushakova 《Chemistry of Heterocyclic Compounds》2005,41(7):921-928
Alkaline hydrolysis of 3-tert-butyl-7,7-bis(hydroxymethyl)-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]-triazin-6(7H)-one can occur in three directions: with cleavage of the tetrahydrotriazine ring, with cleavage of the
thiazolidine ring, and also with opening of both rings. Depending on the process conditions, either the hydrolysis product
corresponding to the first direction or the hydrolytic decomposition products corresponding to the second and third directions
can be obtained in preparative quantities. Hydrolysis of 3,3′-di-tert-butyl-3′,4′-dihydro-2′ H-spiro[(perhydro-1,3-oxazine)-5,7′-thiazolo[3,2-a][1,3,5]triazin]-6′-one in (NH4)2CO3 solution occurs in two steps: in the first step, cleavage of the tetrahydrotriazine ring occurs; and in the second step,
opening of the perhydrooxazine ring occurs.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1089–1097, July, 2005. 相似文献
74.
An analysis of the conformational preferences of two maleimide substituted cyclohexane derivatives proposed as scaffolds for HIV-1 fusion inhibitors is presented. Hybrid Low Mode-Monte Carlo (1:1) conformational searches using seven different force fields were performed in combination with the GBSA(water) solvent model. Low energy structures identified in this way were subjected to geometry optimization on the B3LYP/6-31G** surface. Solvent effects were included in the quantum calculation using the self-consistent reaction field model for water. Quantum results indicate that the 1,3,5-maleimide functionalized 1,3,5-methyl cyclohexane is more stable in the boat conformation, whereas 1,3,5-maleimide functionalized cyclohexane adopts the expected chair conformation with equatorial arms. None of the force fields studied was able to predict the unexpected preference for the boat conformation of 1,3,5-maleimide functionalized 1,3,5-methyl cyclohexane. Comparison of low energy and experimental structures was also performed. 相似文献
75.
Novel core-shell molecularly imprinted polymers were prepared based on zinc oxide quantum dots for the determination of 2,4,6-trichlorophenol by fluorescence. Principally, ZnO quantum dots and 2,4,6-trichlorophenol were chosen as the core substrate and the template molecule, respectively. The specific recognition sites for 2,4,6-trichlorophenol were obtained during the polymerization process in presence of 3-aminopropyltriethoxysilane and tetraethylorthosilicate. Molecularly imprinted ZnO quantum dots were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy and the optical properties were evaluated by spectrofluorometry. Under the optimal conditions, molecularly imprinted ZnO quantum dots were successfully applied to the sensitive determination and selective recognition of 2,4,6-trichlorophenol in water. A linear relationship was obtained to cover the concentration range of 0–160?µmol?L?1 with a correlation coefficient of 0.9931 calculated by the Stern–Volmer equation. The products were used for the determination of 2,4,6-trichlorophenol in the water from local rural areas and the results strongly supported that the molecularly imprinted ZnO quantum dots were suitable for the determination of 2,4,6-trichlorophenol in real examples. 相似文献
76.
《中国化学会会志》2018,65(5):554-560
Some less hindered 2,4,6‐tri‐aryloxy‐s‐triazines were synthesized through the reaction of the corresponding phenols as a starting materials with cyanogen bromide (BrCN) to obtain the corresponding arylcyanates and then trimerized. Unexpectedly, 2,4‐di‐tert‐butyl‐1‐cyanatobenzene derived from 2,4‐di‐tert‐butylphenol did not trimerize but, indeed, yielded bis(2,4‐di‐tert‐butylphenyl) carbonate. The structures of 2,4,6‐tri‐aryloxy‐s‐triazines and bis(2,4‐di‐tert‐butylphenyl) carbonate were characterized by means of IR, 1H, and 13C NMR spectroscopies. Also the structure of the latter compound was studied by X‐ray crystallography. 相似文献
77.
设计并制备了用于检测2,4,6-三氯苯酚的荧光分子印迹。由于铕配合物对模板分子的荧光淬灭作用,可用于荧光检测工具。荧光分子印迹在模板分子浓度范围0~70 nmol·L~(-1)内具有良好的荧光线性响应,相关系数为0.996 28。荧光分子印迹展现出了良好的灵敏度,其最低检出限为3.12 nmol·L~(-1)。荧光分子印迹具有较好的热稳定性,同时选择性检测实验证明荧光分子印迹对2,4,6-三氯苯酚具有良好的特异选择性。实验结果说明荧光分子印迹可用于选择性荧光检测低浓度氯酚类物质。 相似文献
78.
Marcel Klein-Hitpaß Amy D. Lynes Chris S. Hawes Kevin Byrne Wolfgang Schmitt 《Supramolecular chemistry》2018,30(2):93-102
We report here the preparation of a Schiff-base linked organic polymer 1 based on linkages containing the potent supramolecular aggregator benzene-1,3,5-tricarboxamide, connected through 2,6-diiminophenol metal binding pockets into a cross-linked polymer. The morphological and physical properties of this material are studied using electron microscopy techniques, thermal analysis, NMR, fluorescence spectroscopy and gas adsorption studies. The interaction of the polymer 1 with CuII ions is then investigated by soaking the material with methanolic copper acetate solution, and studying the resulting aggregates using EDX microscopy and FTIR spectroscopy. A small-molecule model compound 2 is also prepared and crystallographically characterised to act as a spectroscopic comparison, providing strong evidence that 1 interacts with copper ions through a nucleation/seeding mechanism for the growth of microcrystalline copper acetate deposits, rather than via chemisorption of the copper ions within the diiminophenol binding pockets. Preliminary results suggest a similar mechanism for CoII adsorption, while ZnII ions exhibit a separate interaction mode. 相似文献
79.
A. A. Chesnyuk S. N. Mikhailichenko V. N. Zaplishnyi L. D. Konyushkin S. I. Firgang 《Chemistry of Heterocyclic Compounds》2008,44(3):339-348
We have studied the reaction of 2,5-dimethoxytetrahydrofuran with 4,6-disubstituted 2-amino-1,3,5-triazines with the aim of
obtaining novel coupled polyheterocyclic systems with potential bioactivity. Reaction conditions were optimized. A series
of novel 4,6-disubstituted 2-(1H-1-pyrrolyl)-sym-triazines was obtained. It was found that the product yields depended on
the nature of the substituent in the 4 and 6 positions of the triazine ring and on the reaction conditions.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 440–451, March, 2008. 相似文献
80.
Polysaccharide-based chiral stationary phases (CSPs) are efficient for enantioseparation of many chiral compounds. Immobilized
polysaccharide CSP, as used in the Chiralpak IA column, is a new configuration that was recently introduced for application
in chiral separation. As shown in several previous studies, the characteristics of Chiralpak IA columns cannot be simply extrapolated
from the coated version. In this study, hold-up volume of a Chiralpak IA column was evaluated by static and dynamic methods.
The static pyconometry method gave similar hold-up volumes either as an average value from a range of solvents or a direct
measurement from the carbon tetrachloride-isopropanol (IPA) solvent pair. The dynamic method with 1,3,5-tri-tert-butylbenzene (TTBB) was influenced by the ratio of n-hexane and 2-propanol in the mobile phase but not by the dissolving solvent of TTBB. The two methods resulted in the same
hold-up volume of ∼3.0 mL. TTBB showed weaker retention on the IA column after correction of isobaric thermal expansion of
the mobile phase. During temperature variations in the range of 15–50 °C, the hold-up volume of TTBB was highly reproducible.
Results of this study improve our understanding of the chromatographic features of the immobilized polysaccharide IA column. 相似文献