Encapsulated guest molecules in the dimer of octahydroxypyridine[4]arene

Recently a new type of calix[4]arenes has been synthesized via condensation of 2,6-dihydroxypyridine and a number of aldehydes. This type of pyridine[4]arenes forms capsules consisting of two single pyridine[4]arenes. These capsules can incorporate different guest molecules, like carboxylic acids and amides in this case. We proved that the guest acids really are incorporated inside the cavity of the capsules by electrospray mass spectrometry, NMR spectroscopy, and theoretical calculations.     

Condensed thiolane 1,1-dioxide systems. 3. Two modes of cyclization of N-substituted trans-3-chloro-4-thioureidothiolane 1,1-dioxides

Reaction of trans-3-chloro-A-aminothiolane 1,1-dioxide hydrochloride with aryl isothiocyanates gives, according to the base involved, cis-perhydrothieno[3,4-d]imidazole-2-thione 5,5-dioxides or the hitherto undescribed cis-2-aryliminoperhydrothieno 3,4-d] thiazole 5,5-dioxides.For Part 2, see [1].Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1420–1423, October, 1988.     

Asymmetric synthesis of heteroorganic analogs of natural products. 6. (S)-α-amino-ω-phosphonocarboxylic acids

Alkylation, by -haloalkylphosphonates, of the Ni(II) complex of the Schiff base formed from glycine and (S)-2-N-(N¹-benzylprolyl)-o-aminobenzophenone has been used for the asymmetric synthesis of (S)-2-amino-4-phosphonobutyric and (S)-2-amino-5-phosphonovaleric acids.Institute of Bioorganic Chemistry and Oil Chemistry, Ukrainian Academy of Sciences, 250800 Kiev. A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 397–402, February, 1992.     

Asymmetric synthesis of heteroorganic analogs of natural compounds. 3. General preparative method of diastereo- and enantioselective synthesis of fluorine-containing 2(R), 3(S)-Β-phenylserines

The diastereo- and enantioselective synthesis of the previously unknown 2(R), 3(S)--phenylserines containing fluorine atoms, the O-CHF₂-, O-CF₃-, and CF₃ groups in the benzene ring, was carried out by alkylation of a Ni(II) complex of a Schiff base of glycine with (S)-2-N-(N'-benzylprolyl)aminobenzophenone by fluorine-substituted benzaldehydes. The factors influencing the stereochemical result of the reactions studied are not the steric characteristics of the substituents in benzaldehydes, but their electronic nature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1166–1175, May, 1991.     

Features of Phosphabutadienes Structure: Nmr Spectroscopy and X-Ray Investigation

Abstract

Conjugation effects in various phosphabutadienes are considered.     

Parametric weighted minimax estimates in Monte Carlo methods

In the similar trajectory method (STM), the numerical-statistical modeling of trajectories of particles (radiation quanta) is implemented by applying an auxiliary radiation model. Weighted estimates of the functionals are calculated simultaneously for a set physical parameters values. Theoretical and numerical aspects of choosing an auxiliary model with the aim of minimizing the parametric maximum of the mean-square error in weighted estimates are discussed. Previously known results concerning minimax STM algorithms are refined, and new assertions are obtained. The STM is used to numerically study the parametric dependence of the “transport approximation” error for the particle transmission, absorption, and reflection probabilities.     

Condensed systems from thilane 1,1-dioxide. 4. PMR spectra of cis- and trans-perhydrothieno[3,4-d]-oxa(thia)zole 5,5-dioxides

Examination of the PMR spectra of eleven bicyclic thiolane 1,1-dioxide derivatives has enabled those features of the spectral parameters characteristic of the cis- and trans-orientation of the two condensed five-membered heterocycles to be established. The proton coupling constants show that the conformation of the 1,1-dioxothiolane ring in both types of compound in solution differs from that in the crystalline state, as determined by x-ray analysis.For Communication 3, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1685–1689, December, 1989.     

Reverse inductive effect in the series of trans-3,4-disubstituted thiolane 1,1-dioxides

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, p. 993, July, 1990.     

Intermediate carbene formation in the reaction of thioamides with phosphorus (III) derivatives: Quantum chemical investigation

The reactions of perfluoroalkyl thioamides with trimethyl phosphine, trimethyl phosphite, and tris(dimethylamino)phosphine have been analyzed by means of quantum chemical (DFT and MP2) calculations. The reaction seems to proceed via the nucleophilic attack of the electrophilic carbon atom by the phosphorus lone pair with the formation of cyclic or acyclic adducts. The latter releases the thiophosphate molecule forming perfluoroalkylaminocarbene as the short‐lived intermediate. The reaction of the carbene with the second molecule of trialkyl phosphite yields phosphorus ylide. The ylide undergoes a migration of fluorine from carbon to phosphorus. The reactions of perfluoroalkyl thioamides with phosphines and tris(dimethylamino)phosphine probably proceeds differently. Using alkyl thioamides or amides instead of perfluoroalkyl thioamides also makes the reaction less favorable. The only combination of perfluoroalkyl thioamides with trialkyl phosphite fulfills both the kinetic requirements (moderate activation energies and relative energies for intermediates) and the thermodynamic aspects (higher stabilities of the reaction products compared with the starting materials). © 2013 Wiley Periodicals, Inc.     

A kinetic study of guest displacement reactions on a host-guest complex with a photoswitchable calixarene

The displacement processes of several guests, incorporated in a calixarene host system, were investigated in the gas phase by electrospray ionization-Fourier transform-ion cyclotron resonance (ESI-FT-ICR) mass spectrometry. The complexes resulting from a resorcin[4]arene host with ammonia and sec-butylamine guests were isolated in an ICR-cell, separately using both states of the photoswitch as well as two reference systems for the open and closed forms of the photoswitchable host. The isolated complexes were forced to exchange the guest by using methylamine, ethylamine and sec-butylamine, resulting in different reaction rates for all the measured systems. Especially, the reaction rates of both states of the photoswitch are dependent on the provided guest. Potential side effects like proton exchanges were examined by an H/D-exchange experiment. The results were investigated and supported by quantum chemical calculations (DFT).