A new route of the reaction of EtAlCl2 with α-olefins catalyzed by Ti complexes

A new method for the synthesis of dialkyl(ethyl)alanes by the reaction of EtAlCl₂ with -olefins in the presence of Mg and a catalytic amount of Cp₂TiCl₂ (Ti(OPrⁱ)₄, Ti(OBuⁿ)₄) in THF was developed.     

Unusual transformation of a fluoroalkyl-containing β-aminovinyl ketone

Russian Chemical Bulletin -     

Effect of the Heterocyclic Ligand in Iron Porphyrinate Complex on the Strength of the Bond Between Iron and CO Molecule

The geometry and the electronic structure of iron porphyrinate complexes with various heterocyclic molecules in the fifth coordination position and a CO molecule in the sixth position were studied by density functional theory calculations. In the series of complexes with furan, imidazole, and pyrimidine, the bond between the Fe atom and CO is weakened due to the decrease in the overlap of the corresponding AOs.     

One-step synthesis of α-hydroxy-α-azinylcyanoacetic esters from α-nitro derivatives of α-azinylcyanoacetic esters

When boiled in aromatic hydrocarbons, solutions of α-nitro-α-azinylcyanoacetic esters of the pyrimidine, pyrazine, ands-triazine series gave the corresponding α-hydroxy derivatives of α-azinylcyanoacetic esters in high yields. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1407–1409, July, 1997.     

Mechanism of the oxidative carbonylation of terminal alkynes at the ≡C-H bond in solutions of palladium complexes

The formation mechanism of the active catalyst in the oxidative carbonylation of terminal alkynes at the ≡C-H bond has been investigated for the catalytic system Pd(OAc)₂-PPh₃-p-benzoquinone (Q)-MeOH. It has been demonstrated by NMR spectroscopy, X-ray crystallography, and kinetic measurements that the catalytically active palladium is in the oxidation state 0 and is bound into complexes stabilized by p-benzoquinone (PdL₂Q, where L = PPh₃). A mechanism is suggested for the catalytic process, which includes the formation of the complex PdL₂Q, the oxidative addition of the alkyne to this complex at the ≡C-H bond, the insertion of CO into the Pd-C bond, and steps in which hydride hydrogen is intramolecularly transferred to the p-quinone.     

Sesquiterpene Lactones and Flavonoids from <Emphasis Type="Italic">Artemisia albida</Emphasis>

The five known lactones matricarin, austricin, canin, and achillin guaianolides and argolide germacranolide and the two flavonoids eupatilin and its 7-O-methyl ester were isolated for the first time from the aerial part of Artemisia albida Willd. The structure of eupatilin was confirmed by an x-ray structure analysis. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 568–570, November–December, 2005.     

Synthesis,complexation, and photochemistry of benzobisthiazole-based bis(crown ether)

Benzobisthiazole-based bis(crown ether) was synthesized and its complexation with alkali and alkaline earth cations was studied. Photochemical transformations of the free ligand and its complexes with alkaline earth cations involve E,Z-photoisomerization and [2+2] photocycloaddition. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2056–2065, September, 2005.     

A hexacyclic ent-trachylobane diterpenoid possessing an oxetane ring from Mitrephora glabra

[chemical reaction: see text]. Three new ent-trachylobane diterpenoids (1-3) were isolated and structures elucidated from Mitrephora glabra Scheff. (Annonaceae). Mitrephorone A (1) possesses a hexacyclic ring system with adjacent ketone moieties and an oxetane ring, both of which are unprecedented among trachylobanes. All compounds were evaluated for cytotoxicity against a panel of cancer cells, where 1 displayed the most potent and broadest activity, and against a battery of antimicrobial assays, where all compounds were approximately equipotent.     

QSPR Modeling of the Reactivity Parameters of Monomers in Radical Copolymerizations

For a series of monomers, QSPR test analysis is performed by optimizing the correlation weights of the local invariants of molecular graphs representing monomer structures in order to construct models of the reactivity parameters of monomers Q and e. This approach may be used as a tool in reactivity predictions for monomers for which no experimental data on Q and e are available.Original Russian Text Copyright © 2004 by A. A. Toropov, V. O. Kudyshkin, N. L. Voropaeva, I. N. Ruban, and S. Sh. Rashidova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 994–998, November–December, 2004.     

Synthesis of partially hydrogenated pyrazolo[3,4-b]quinolinones by condensation of 3-amino-5-methylpyrazole with aromatic aldehydes and dimedone

Cyclocondensation of 3-amino-5-methylpyrazole with 2-arylmethylidene-5,5-dimethylcyclohexane-1,3-diones or 9-aryl-3,3,6,6-tetramethyl-2,3,4,5,6,7,8,9-octahydro-1H-xanthene-1,8-diones, as well as with synthetic precursors of the latter (para-substituted benzaldehydes and dimedone), in dimethylformamide or methanol gives the corresponding 4-aryl-3,7,7-trimethyl-2,4,6,7,8,9-hexahydropyrazolo[3,4-b]quinolin-5-ones. The structure of 4-(4-methoxyphenyl)-3,7,7-trimethyl-2,4,6,7,8,9-hexahydropyrazolo[3,4-b]quinolin-5-one was proved by the X-ray diffraction data.