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1.
2.
Levoglucosenone reacts with α-aminoazoles to yield azolo[1,5-a]pyrimidine systems fused with a carbohydrate fragment. The reaction oocurs much more smoothly than in the case of other α,β-unsaturated
ketones. The reactions of levoglucosenone with β-dicarbonyl compounds (dimedone, barbituric acid) in the presence of a base
results in the pyran ring closure, which has never been observed earlier in reactions of β-dicarbonyl compounds with α,β-unsaturated
ketones under the conditions of basic catalysis. The structures of products were established by IR and NMR spectroscopy.
For Part 3, see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 553–558, March, 1997. 相似文献
3.
Muhammad Adil Khan Shahid Khan Samet Erden Muhammad Samraiz 《Mathematical Methods in the Applied Sciences》2022,45(1):36-48
There are many useful applications of Jensen's inequality in several fields of science, and due to this reason, a lot of results are devoted to this inequality in the literature. The main theme of this article is to present a new method of finding estimates of the Jensen difference for differentiable functions. By applying definition of convex function, and integral Jensen's inequality for concave function in the identity pertaining the Jensen difference, we derive bounds for the Jensen difference. We present integral version of the bounds in Riemann sense as well. The sharpness of the proposed bounds through examples are discussed, and we conclude that the proposed bounds are better than some existing bounds even with weaker conditions. Also, we present some new variants of the Hermite–Hadamard and Hölder inequalities and some new inequalities for geometric, quasi-arithmetic, and power means. Finally, we give some applications in information theory. 相似文献
4.
Samet AV Niyazymbetov ME Semenov VV Laikhter AL Evans DH 《The Journal of organic chemistry》1996,61(25):8786-8791
Regioselective Michael addition of nitro and heterocyclic compounds to levoglucosenone, 1, is effectively catalyzed by amines and also by cathodic electrolysis. In comparison to the base-catalyzed reaction, it was found that under electrochemical conditions the reaction proceeds under milder conditions and with higher yields. Cathodically-initiated Michael addition of thiols to levoglucosenone using small currents produces the previously unknown threo addition product in several instances. The normal erythro isomer, identified as the kinetic product, tends to be formed when large currents are used. In contrast, slow, low current electrolyses promote equilibration of the two forms so that erythro can be converted to threo by the retro reaction and readdition. Addition of 2-naphthalenethiol to (R)-(+)-apoverbenone is also reported. 相似文献
5.
Chirkova Zh. V. Kabanova M. V. Filimonov S. I. Samet A. V. Stashina G. A. Sudzilovskaya T. N. 《Russian Chemical Bulletin》2018,67(6):1083-1087
Russian Chemical Bulletin - Chlorination of 1-hydroxyindole-5,6-dicarbonitriles and 1-hydroxypyrrolo[3,4-f]indole-5,7(1H,6H)-diones with N-chlorosuccinimide afforded previously unknown... 相似文献
6.
Awatif Alqahtani Mohamed Jleli Bessem Samet 《Mathematical Methods in the Applied Sciences》2019,42(3):861-870
In this paper, some nonlocal in time differential inequalities of Sobolev type are considered. Using the nonlinear capacity method, sufficient conditions for the nonexistence of nontrivial global classical solutions are provided. 相似文献
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9.
Samet Solak Mehmet Karakuş 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1054-1061
Abstract2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson’s reagent: LR) was reacted with 1,2:5,6-di-O-cyclohexylidene-α-D-glucofuranose and 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose in toluene and gave rise to crude dithiophosphonic acids. The crude dithiophosphonic acids were treated with excess triethylamine and the triethylammonium salts of dithiophosphonic acids (1) and (2) were isolated by crystallization method. Compounds 1 and 2 were characterized by elemental analysis, IR, and NMR (1H-, 13C- and 31P-) spectroscopies and mass spectrometry. In addition, NMR spectra, the electronic properties (the electronic chemical potential, electronegativity, chemical hardness and the global electrophilicity index) and NBO analysis of compound 2 have been calculated by using the Gaussian 16?W program. The electronic properties were calculated using Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energies by density functional method (DFT/B3LYP) at 6-31G(d,p) level. The HOMO and LUMO energies are ?5.9 and ?0.72?eV, respectively. The HOMO–LUMO energy difference is 5.18?eV and this value shows that compound 2 has a high stability and low reactivity. 相似文献
10.