Aerobic oxidative amination of unactivated alkenes catalyzed by palladium

The first examples of palladium-catalyzed oxidative amination of unactivated alkyl olefins have been identified. To be successful, these reactions must be conducted under cocatalyst-free conditions that involve direct dioxygen-coupled turnover of the palladium catalyst. The oxidative amination products of norbornene and other cyclic alkenes implicate a cis-aminopalladation mechanism.     

Cu-Catalyzed Oxidative Phosphorylation of Alkanols with White Phosphorus and H 2 O 2

Oxidative phosphorylation of alkanols with white phosphorus in the presence of catalytic amounts of CuCl 2 has been effected. The reaction proceeds in the aqueous H 2 O 2 --HCl system exothermically to form dialkylphosphites and trialkylphosphates in a total yield of up to 35%. Conditions for selective synthesis of dialkylphosphites in moderate yield have been found.     

Method for Reduced Basis Discovery in Nonstationary Problems

Doklady Mathematics - Model reduction methods allow to significantly decrease the time required to solve a large ODE system in some cases by performing all calculations in a vector space of...     

Kinetic studies on the formation of sulfonyl radicals and their addition to carbon-carbon multiple bonds

The reactions of α-hydroxyl and α-alkoxyl alkyl radicals with methanesulfonyl chloride (MeSO(2)Cl) have been studied by pulse radiolysis at room temperature. The alkyl radicals were produced by ionizing radiation of N(2)O-saturated aqueous solution containing methanol, ethanol, isopropanol, or tetrahydrofuran. The transient optical absorption spectrum consisted of a broad band in the region 280-380 nm with a maximum at 320 nm typical of the MeSO(2)(?) radical. The rate constants in the interval of 1.7 × 10(7)-2.2 × 10(8) M(-1) s(-1) were assigned to an electron-transfer process that leads to MeSO(2)Cl(?-), subsequently decaying into MeSO(2)(?) radical and Cl(-). The rate constants for the addition of CH(3)SO(2)(?) to acrolein and propiolic acid were found to be 4.9 × 10(9) M(-1) s(-1) and 5.9 × 10(7) M(-1) s(-1), respectively, in aqueous solutions and reversible. The reactivity of tosyl radical (p-CH(3)C(6)H(4)SO(2)(?)) toward a series of alkenes bearing various functional groups was also determined by competition kinetics in benzene. The rate constants for the addition of tosyl radical to alkenes vary in a much narrower range than the rate constants for the reverse reaction. The stabilization of the adduct radical substantially contributes to the increase of the rate constant for the addition of tosyl radical to alkenes and, conversely, retards the β-elimination of tosyl radical.     

Threshold effects in the interaction of a plasma with injected pellets in the T-10 tokamak

Sharp changes (peaks and dips) of the radiation signal from carbon pellets injected into the plasma in the tokamak are related to the level of introduced disturbances. The threshold size (near 0.3 mm) is determined beginning with which a pellet in the ohmic plasma of the T-10 tokamak initiates tearing processes in a region with q < 2 and Kadomtsev reconnection in the central region with q = 1. A model describing ablation under the conditions of pellet-induced reconnections is proposed. This model satisfactorily describes the observed shape of the ablation rate curve.     

An unusual reaction of 1,1-dilithio-2,3,4,5-tetraphenyl-1-silacyclopentadiene with diphenylcyclopropenone: synthesis of 1,4-Bis(trimethylsiloxy)-2,3,5,6-tetraphenylbenzene

Reaction of 1,1-dilithio-2,3,4,5-tetraphenylsilole (*5*) with diphenylcyclopropeneone proceeds with loss of silicon to yield the dilithium salt of 2,3,4,5-tetraphenyl-1,4-hysroquinone (*8*), which was trapped with trimethylchlorosilane to yield 1,4-bis(trimethylsiloxy)-2,3,5,6-tetraphenylbenzene, *9*. A possible pathway for the formation of *8* and *9* is proposed.     

On-line investigation of short-lived Os and Re isotopes as a test for chemical studies of 108 (Hs) and 107 (Bh) elements in HCl solutions by continuous chromatography

On-line chemistry studies of short-lived isotopes of Os and Re, as homologs of 108 (Hs) and 107 (Bh), respectively, produced in the nuclear reactions at the (LNR, Dubna) cyclotron have been carried out. It was shown, that Os and Re are not sorbed on cation exchangers, but very strongly sorbed on anion exchangers from diluted HCl solutions. Re is also retained by a TOPO containing sorbent and may be separated from Os. The possibilities of chemical species and oxidation states investigation of short-lived transactinide elements by continuous chromatography have been shown. This revised version was published online in July 2006 with corrections to the Cover Date.     

Novel quinine,lupinine, and anabasine derivatives containing dithiophosphinate groups

A three-component, atom-economic reaction between natural quinine, lupinine, or anabasine, secondary phosphines, and elemental sulfur occurs under mild conditions to yield previously unknown optically active dithiophosphinates.     

Spectral manifestations of intramolecular interactions in acid chlorides of unsaturated phosphorus acids

The UV absorption spectra of acid dichlorides of aryl phosphonic and phosphinic acids in the 185–340 nm region were investigated. Hypothetical conclusions are made concerning the nature of the electronic transitions in phosphorus-containing benzenes. The interaction of phosphorus-containing group with a -electron system of the aromatic radical is characterized on the basis of the data obtained. The role of vacant orbitals of phosphorus and chlorine atom, unshared pair p^III, and p–d bond of the phosphoryl group in the investigated effects is examined.Izvestiya VUZ. Fizika, No. 3, pp. 31–36, March, 1973.