Ресурсный центр «Магнитно-резонансные методы исследования»

M. A. Kinzhalov , A. S. Legkodukh, T. B. Anisimova, A. S. Novikov, V. V. Suslonov, K. V. Luzyanin , V. Yu. Kukushkin

“Tetrazol-5-ylidene Gold(III) Complexes frоm Sequential [2 + 3] Cycloaddition of Azide to Metal-Bound Isocyanides and N4 Alkylation”

Organometallics, 2017, 36, 3974–3980
DOI: 10.1021/acs.organomet.7b00591

The reaction between equimolar amounts of the isocyanide complexes [AuCl₃(CNR)] [R = 2,6-Me₂C₆H₃ (Xyl), 1a; 2,4,6-Me₃C₆H₂ (Mes), 1b; Cy, 1c; t-Bu, 1d] and tetrabutylammonium azide (2) proceeds in CH₂Cl₂ at room temperature for ∼10 min to furnish the gold(III) tetrazolates [n-Bu₄N][AuCl₃(CN₄R)] (3a–d), which were obtained in 89–95% yields after purification. Subsequent reaction between equimolar amounts of 3a–d and methyl trifluoromethanesulfonate (MeOTf) proceeds in CH₂Cl₂ at −70 °C for ∼30 min to give the corresponding gold(III) complexes [AuCl₃(CaN(Me)N₂NbR)]a–b (5a–d) bearing 1,4-disubstituted tetrazol-5-ylidene ligands (69–75%). Complexes 3a–d were obtained as pale-yellow solids and characterized by elemental analyses (C, H, N), HRESI–-MS, FTIR, and 1H and 13C{1H} NMR spectroscopies. Complexes 5a–d were obtained as colorless solids and characterized by elemental analyses (C, H, N), HRESI+-MS, and 1D (¹H and ¹³C{1H}) and 2D (¹H,¹³C-HMBC) NMR spectroscopies. In addition, the structures of 3a, 3b, 3c, and 5a were established by single-crystal X-ray diffraction. Analysis of the Wiberg bond indices (WI) for gas phase-optimized model structures of 3a–c and 5a computed using the natural bond orbital (NBO) partitioning scheme disclosed a higher degree of electron density delocalization in the CN₄ moiety of carbene 5a when compared to tetrazolate 3a–c. Results of DFT calculations for a model system reveal that the mechanism for the cycloaddition of an azide to the isocyanide ligand in [AuCl₃(CNMe)] is stepwise and involves nucleophilic attack of N3– on the N atom of CNMe followed by ring closure. The addition is both kinetically and thermodynamically favorable and occurs via the formation of an acyclic NNNCN intermediate, whereas the cyclization is the rate-determining step.

Поздравляем специалиста нашего ресурсного центра Артема Сергеевича Гревцева с успешной защитой кандидатской диссертации «Полиольный синтез селеноиндатов-галлатов меди в микроволновом поле». Желаем ему дальнейших творческих успехов!

В Ноябре выполнено 2286 заявок на сервисные измерения.

Измерено:

• 2169 спектр ¹H
• 374 спектра ¹³C
• 119 спектров DEPT
• 53 спектров COSY
• 15 спектра NOESY
• 54 спектра ³¹Р
• 168 спектров ¹⁹F

Выполнено 231 заявок на исследовательскую работу.

A.S. Filatov, N.A. Knyazev, A.P. Molchanov, T.L. Panikorovsky, R.R. Kostikov, A.G. Larina, V.M. Boitsov, A.V. Stepakov

“Synthesis of Functionalized 3-Spiro[cyclopropa[a]pyrrolizine]- and 3-Spiro[3-azabicyclo[3.1.0]hexane]oxindoles from Cyclopropenes and Azomethine Ylides via [3 + 2]-Cycloaddition”

J. Org. Chem., 2017, 82 (2), 959–975
DOI: 10.1021/acs.joc.6b02505

3-Spiro [cyclopropa [a]pyrrolizine]- and 3-spiro [3-azabicyclo [3.1.0] hexane] oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro.

A.N. Shestakov, A.S. Pankova, P. Golubev, A.F. Khlebnikov, M.A. Kuznetsov

“Brønsted acid mediated cyclizations of ortho-aryl(ethynyl)pyrimidines”

Tetrahedron, 2017, 73 (27-28), 3939–3948
DOI: 10.1016/j.tet.2017.05.070

A high-yielding procedure for the synthesis of 5-aryl-4-(arylethynyl)pyrimidines from easily available 2-aryl-3-hydroxyacrylates is reported. These pyrimidines readily undergo cyclization in strong Brønsted acids and, depending on the substitution in alkynylpyrimidines and the water content of the reaction mixture, yield either benzo[f]quinazolines or derivatives of spiro[cyclohexa-2,5-diene-1,5′-cyclopenta[d]pyrimidin]-4-one. In most cases the cyclization proceeds nearly quantitatively. DFT calculations support the proposed mechanisms induced by the protonation of the triple bond in 5-aryl-4-(arylethynyl)pyrimidines. Fluorescent properties of the obtained heterocycles are also described.

A.I. Solomatina, I.O. Aleksandrova, A.J. Karttunen, S.P. Tunik, I.O. Koshevoy

“Dibenzothiophene-platinated complexes: probing the effect of ancillary ligands on the photophysical performance”

Dalton Transactions, 2017, 46, 3895-3905
DOI: 10.1039/C7DT00349H

Cyclometalation of dibenzothienyl-pyridine (HPyDBT) afforded a series of platinum(II) complexes Pt(PyDBT)(L)Cl (L = DMSO, 1; P(p-C6H4-X)3 (X = H, 2; CF3, 3; OMe, 4; NPh2, 5); 1,3,5-triaza-7-phosphaadamantane, 6; 2,6-dimethylphenyl isocyanide, 7). Chelating bidentate LL ligands formed cationic compounds [Pt(PyDBT)(LL)]+ (LL = 1,2-bis(diphenylphosphino)benzene, 8; 2,2′-bipyridine, 9; 1,10-phenanthroline, 10). Oxidation of a thienyl sulfur atom allowed for the isolation of the sulfone derivative Pt(PyDBT)(PPh3)Cl (11). The title complexes were characterized crystallographically (except 7). Investigation of their photophysical behavior revealed solid state phosphorescence with quantum yields up to 0.45 for neat powders. The ancillary ligands L show a minor influence on the emission energies of the neutral compounds, but affect dramatically the intensity of luminescence. In contrast, the cationic species with diimine ligands demonstrate a significant contribution of the LL fragments into the emissive T1 states that leads to a certain mixing of 3IL and 3LL′CT transitions and causes a substantial bathochromic shift of emission.