Archive for December 30, 2015
D.S. Ryabukhin, A.V. Vasilyev
“A synthesis of 4-aryl quinolin-2(1H)-ones by acidic zeolite promoted intramolecular cyclization of N-aryl amides of 3-arylpropynoic acids”
Tetrahedron Lett., 2015, 56, 2200-2202
N-Aryl amides of 3-arylpropynoic acids are intramolecularly cyclized into 4-aryl quinolin-2(1H)-ones in high yields without any by-products under the action of acidic zeolite CBV-720 in benzene at 130 °C in a glass high pressure tube.
Thanks to our users for creating a New Year’s entourage!
A.V. Galenko, A.F. Khlebnikov, M.S. Novikov, M.S. Avdontseva
“Synthesis of 3-(1,2-dioxoethyl)- and 2,3-dicarbonyl-containing pyrroles”
Tetrahedron, 2015, 71, 1940-1951
The transition metal-catalyzed reaction of 2H-azirines with 1,2,4-tricarbonyl compounds leads to 3-(1,2-dioxoethyl)- and 2,3-dicarbonyl-pyrrole derivatives, useful building blocks for the preparation of 3-heterocyclyl pyrroles and pyrroles fused with heterocycles. The influence of catalysts and the reaction conditions on the yields of pyrroles and the regioselectivity of the reaction were studied. Experimental and theoretical results suggest that the reaction proceeds via the formation of an intermediate azirine–metal complex and subsequent nucleophilic N–C3 bond cleavage.
Mikhail Vovk has conducted a lecture for first year students of physical faculty.
Zhou To and his colleagues (Centre of Education of the Russian language, Zhengzhou University) have visited Center for Magnetic Resonance.
Peter Tolstoy has presented a lecture “SPbU Research Park, Center for Magnetic Resonance: possibilities of joint research projects” at the Berlin – St. Petersburg Workshop on Structure and Dynamics of Nanoscopic Matter.
N.A. Danilkina, A.G. Lyapunova, A.F. Khlebnikov, G.L. Starova, S. Brase, I.A. Balova
“Ring-Closing Metathesis of Co2(CO)6–Alkyne Complexes for the Synthesis of 11-Membered Dienediynes: Overcoming Thermodynamic Barriers”
J. Org. Chem., 2015, 80, 5546-5555
The feasibility of ring-closing metathesis (RCM) as a synthetic entry to 10- and 11-membered dienediynes fused to a benzothiophene core was explored by experimental and theoretical investigations. An established sequence of iodocyclization of o-(buta-1,3-diynyl)thioanisoles followed by Sonogashira coupling to form diethynylbenzothiophenes was used to synthesize terminal benzothiophene-fused enediyne diolefins as substrates for RCM. Encountering an unexpected lack of reactivity of these substrates under standard RCM conditions, we applied DFT calculations to reveal that the underlying cause was a positive change in Gibbs free energy. The change in Gibbs free energy was also found to be positive for RCM of indole- and benzannulated terminal diolefins when affording smaller than 12-membered rings. We found that modification of the enediyne–diolefin substrate as the Co2(CO)6–alkyne complex allowed the target benzothiophene-fused 11-membered dienediyne to be obtained via RCM; the alkyne complexation strategy therefore provides one valid technique for overcoming challenges to macrocyclization of this kind.
Peter Tolstoy has introduced СMR and has presented a lecture “Proton Transfer in Short and Strong Hydrogen Bonds: Geometries, Solvent Effects, NMR and UV/NMR Spectra” at the seminar in Chemistry Institute of the University of Jyväskylä (Finland).