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Archive for April 27, 2015

Russian Journal of Coordination Chemistry, 2015, 41(6), 357-364

E.A. Katlenok, A.A. Zolotarev, A. U. Ivanov, S.N. Smirnov, R.I. Baychurin, K.P. Balashev

Title in rus: “Cтроение, оптические и электрохимические свойства биядерных платинированных комплексов 2-фенилбензотиазола с мостиковыми 2-меркаптопроизводными тиазолина, 1-метилимидазола и пиримидина”

Org. Lett. 2015

A.S. Pankova, A.Yu. Stukalov, M.A. Kuznetsov

“Synthesis of 2‑(Hetero)aryl-5-(trimethylsilylethynyl)oxazoles from 2 (Hetero)arylacrylic Acids”

Org. Lett., 2015, accepted

DOI:10.1021/acs.orglett.5b00009

A three-step method for the synthesis of 2-(hetero)-aryl-5-(trimethylsilylethynyl)oxazoles is described. Easily accessible bis(trimethylsilyl)acetylene and acrylic acid derivatives are used as starting materials for the preparation of mono- and disubstituted 5-(trimethylsilyl)pent-1-en-4-yn-3-ones. Oxidative phthalimido-aziridination of these enynones provides the key 2-acyl-1-phthalimido-aziridines that are further utilized in the thermal expansion of the three-membered ring to furnish the target functionalizable oxazoles.

J. Org. Chem. 2015

P.R. Golubev, A.S. Pankova, M.A. Kuznetsov

“Regioselective Transition-Metal-Free Synthesis of 2‑(Trimethylsilylmethylene)pyrrol-3-ones by Thermal Cyclization of Acetylenic Enamines”

J. Org. Chem., 2015, accepted

DOI:10.1021/acs.joc.5b00398

Acetylenic enamines generated in situ from readily available enynones and primary amines undergo thermal cyclization in diphenyl ether providing easy access to 4-aryl-2-(trimethylsilylmethylene)-1,2-dihydro-3H-pyrrol-3-ones. This reaction is inherently versatile, allowing for variations of substituents in both enynone and amine. Full regioselectivity along with short reaction time (1−2 h) and simple workup afford single products in good to excellent isolated yields. Fluorescent properties of the obtained compounds were studied.>

J. Am. Chem. Soc. 2015

S.N. Britvin, A. Lotnyk

“Water-Soluble Phosphine Capable of Dissolving Elemental Gold: The Missing Link between 1,3,5-Triaza-7-phosphaadamantane (PTA) and Verkade’s Ephemeral Ligand”

J. Am. Chem. Soc., 2015, accepted

DOI:10.1021/jacs.5b01851

2015 04 27 (Britvin)

We herein describe a tricyclic phosphine with previously unreported tris(homoadamantane) cage architecture. That water-soluble, air- and thermally stable ligand, 1,4,7-triaza-9-phosphatricyclo[5.3.2.14,9]tridecane (hereinafter referred to as CAP) exhibits unusual chemical behavior toward gold and gold compounds: it readily reduces Au(III) to Au(0), promotes oxidative dissolution of nanocrystalline gold(0) with the formation of water-soluble trigonal CAP−Au(I) complexes, and displaces cyanide from [Au(CN)2]− affording triangular [Au(CAP)3]+ cation. From the stereochemical point of view, CAP can be regarded as an intermediate between 1,3,5-triaza-7-phosphaadamantane (PTA) and very unstable aminophosphine synthesized by Verkade’s group: exahydro-2a,4a,6a-triaza-6bphosphacyclopenta[cd]pentalene. The chemical properties of CAP are likely related to its anomalous stereoelectronic profile: combination of strong electron-donating power (Tolman’s electronic parameter 2056.8 cm−1) with the low steric demand (coneangle of 109°). CAP can be considered as macrocyclic counterpart of PTA with the electron-donating power approaching that of strongest known phosphine electron donors such as P(t-Bu)3 and PCy3. Therefore, CAP as sterically undemanding and electronrich ligand populates the empty field on the stereoelectronic map of phosphine ligands: the niche between the classic tertiary phosphines and the sterically undemanding aminophosphines.

Our visitors

On April 24th 2015 Behruz Abtahi (representative of the Ministry of Science, Research and Technologies of Iran, Counsellor of the Embassy of the Iranian Republic), Mohammad Mehdi Tehranchi (Chancellor of Shahid Beheshti University, Tehran) and Kayvan Hosseini (Assistant professor at Allameh Tabatabai University, Tehran) have visited the center.

BioNMR

2015 04 23(2)

A postdoc in Prof. Dr. Nikolay R. Skrynnikov’s BioNMR laboratory, Kerstin Kampf, is researching temperature dependence of dynamics in intrinsically disordered proteins.

Russ. J. Org. Chem. 2015, 51, 368-372

A.P. Molchanov, Yu.V. Malinina, R.R. Kostikov, A.V. Stepakov

“Regioselective Cycloaddition of C,N-Diarylnitrones to Arylallenes and of N-Aryl-C-carbamoylnitrones to Methyl Buta-2,3-dienoate”

Russ. J. Org. Chem, 2015, 51, 368-372

DOI:10.1134/S1070428015030136

2015 04 22(1)

Cycloadditions of C,N-diarylnitrones to non-activated arylallenes and of N-aryl-C-carbamoylnitrones to methyl buta-2,3-dienoate regioselectively afforded mixtures of diastereoisomeric substituted 4-methylideneisoxazolidines.

Russ. J. Org. Chem. 2015, 51, 210-213

A.V. Stepakov, A.G. Larina, A.P. Molchanov

“Isomerization of Dimethylenecyclopropanes in Benzofulvenes in the Presence of Lewis Acids”

Russ. J. Org. Chem, 2015, 51, 210-213

DOI:10.1134/S1070428015020128

2015 04 22(2)

1,1-Diaryl-2-(1-methylethylidene)-3-methylenecyclopropanes in the presence of Lewis acid isomerize in benzofulvene derivatives.

Spectrochimica Acta, Part A 2015

T. Kozlecki, P.M. Tolstoy, A. Kwocz, M.A. Vovk, A. Kochel, I. Polowczyka, P.Yu. Tretyakov, A. Filarowski

“Conformational state of β-hydroxynaphthylamides and barriers for the rotation of the amide group”

Spectrochimica Acta, Part A, 2015, accepted

2015 04 20

Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analysed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of 1H and 13C NMR signals. A tentative correlation between the barrier height and the strength of OHO bond was proposed. Calculations of the potential energy profiles for the rotations around CC and CN bonds were done. In case of morpholine derivative experimental indications of additional dynamics: chair-chair ‘ring flip’ in combination with the twisting around CC bond were obtained and confirmed by quantum chemistry calculations.

March

Total in March 1988 service applications were carried out.
All together measured:

  • 1871 1H spectra
  • 400 13C spectra
  • 216 DEPT spectra
  • 41 COSY spectra
  • 11 NOESY spectra
  • 88 31P spectra
  • 93 19F spectra

212 applications were carried out which jointly took 2540 hours of measurements.