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1.
E. V. Gromachevskaya A. G. Sakhabutdinov V. G. Kul'nevich I. S. Arustamova R. B. Valeev B. A. Bazhenov 《Chemistry of Heterocyclic Compounds》1991,27(5):502-503
It was shown that the reaction of o-hyroxyphenyldiphenylmethanol with benzaldehyde labeled with 17O and 18O isotopes proceeds in such a way that oxygen atoms of the starting phenoloalcohol are retained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 632–633, May, 1991. 相似文献
2.
E. A. Yatsynich D. V. Petrov F. A. Valeev V. A. Dokichev 《Chemistry of Natural Compounds》2003,39(4):337-339
The 1,3-dipolar cycloaddition of diazomethane to levoglucosenone was found to occur regio- and stereoselectively to form optically active 9,11-dioxa-4,5-diazatricyclo[6.2.1.02,6]undec-4-en-7-one. Levoglucosenone was found to react with methyldiazoacetate to give the 2:1 adduct. 相似文献
3.
A. S. Gromova V. I. Lutskii A. A. Semenov R. B. Valeev G. A. Kalabin Yu. N. El'kin 《Chemistry of Natural Compounds》1985,21(5):629-635
The epigeal part ofThalictrum minus L. has yielded a new bidesmoside — thalicoside B — which has the structure of oleanolic acid 28-O-β-D-glucopyranoside 3-O-[O-α-L-rhamnopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranoside]. 相似文献
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5.
B. T. Sharipov A. N. Davydova F. A. Valeev 《Russian Journal of Organic Chemistry》2018,54(10):1463-1468
A short synthetic route to bicyclo[6.2.1]undec-9-ene-2,6-dione has been developed on the basis of retro-aldol reaction of 7-hydroxytricyclo[6.2.1.02,7]undec-9-en-3-one obtained from the Diels–Alder adducts of 3-tosylcyclohex-2-en-1-one with cyclopentadiene. 相似文献
6.
Vasilyev V. N. Sazonenko D. A. Kukushkin D. E. Bakholdin A. V. Valyavin G. G. Bychkov V. D. Galazutdinov G. A. Valeev A. F. Yushkin M. V. 《Optical Review》2016,23(5):878-884
The paper presents a critical analysis and modernization of separate elements of the optical layout of a high-resolution spectrograph with fiber input for the Big Azimuthal Telescope of the Special Astrophysical Observatory. The modernization is directed mainly at enhancing the light efficiency and making it possible to produce the spectrograph using domestic manufacturers. Renovated versions of the cross-dispersion grism, the projection camera, and the overall characteristics of the system are presented. The resulting efficiency of the whole instrument is given.
相似文献7.
Steven S. Wesolowski Edward F. Valeev Rollin A. King Victor Baranovski Henry F. Schaefer III 《Molecular physics》2013,111(16):1227-1231
Atomic natural orbital (ANO) basis sets for calcium may produce surprisingly poor atomic and molecular properties and energetics. The weaknesses in these basis sets may be traced primarily to deficiencies within the sets of d functions which are incapable of effectively correlating the 3s and 3p electrons. Examples are given which show that addition of tight d functions to the ANO basis is required to achieve qualitatively correct energetics and structures for conventionally bonded calcium compounds. 相似文献
8.
The review summarizes data on natural sources, the history of the structure determination, and transformations of the rare sesquiterpenoid (+)-δ-cadinol. 相似文献
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10.
In this paper, various implementations of the analytic Hartree–Fock and hybrid density functional energy second derivatives are studied. An approximation-free four-centre implementation is presented, and its accuracy is rigorously analysed in terms of self-consistent field (SCF), coupled-perturbed SCF (CP-SCF) convergence and prescreening criteria. The CP-SCF residual norm convergence threshold turns out to be the most important of these. Final choices of convergence thresholds are made such that an accuracy of the vibrational frequencies of better than 5 cm?1 compared to the numerical noise-free results is obtained, even for the highly sensitive low frequencies (<100–200 cm?1). The effects of the choice of numerical grid for density functional exchange–correlation integrations are studied and various weight derivative schemes are analysed in detail. In the second step of the work, approximations are introduced in order to speed up the computation without compromising its accuracy. To this end, the accuracy and efficiency of the resolution of identity approximation for the Coulomb terms and the semi-numerical chain of spheres approximation to the exchange terms are carefully analysed. It is shown that the largest performance improvements are realised if either Hartree–Fock exchange is absent (pure density functionals) and otherwise, if the exchange terms in the CP-SCF step of the calculation are approximated by the COSX method in conjunction with a small integration grid. Default values for all the involved truncation parameters are suggested. For vancomycine (176 atoms and 3593 basis functions), the RIJCOSX Hessian calculation with the B3LYP functional and the def2-TZVP basis set takes ~3 days using 16 Intel® Xeon® 2.60GHz processors with the COSX algorithm having a net parallelisation scaling of 11.9 which is at least ~20 times faster than the calculation without the RIJCOSX approximation. 相似文献