Aza Diels—Alder reactions of methyl trifluoropyruvate sulfonyl- and phosphorylimines with 1,3-dienes

2-Trifluoromethyl-substituted 1,2,3,6-tetrahydro-2-pyridyl carboxylates were synthesized in one step by the aza Diels—Alder reactions of methyl trifluoropyruvate sulfonyl- and phosphorylimines with 1,3-dienes.     

Telomerization of ethylene with 1,1,1,3-tetrachloropropane in the presence of iron pentacarbonyl and isopropyl alcohol

Conclusions Polychlorinated hydrocarbons containing the CCl₃ group can be used as telogens in the telomerization of olefins in the presence of iron pentacarbonyl and i-C₃H₇OH. The formation of the telomer homologs in high yield obeys the general rules that were established for the given initiating system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2837–2839, December, 1971.     

Deviation from a maxwellian distribution in chemical reactions

It is shown that Enskog and Chapman's method of solving the gaskinetic equation is not applicable to perturbations in the Maxwellian distribution due to chemical reaction. The method is extended to finite perturbations of the equilibrium distribution function in the high-energy region. Detailed calculations for given reaction crosssections show that the distribution function and the reaction rate may differ substantially from the equilibrium ones.     

Synthesis and Structure of 2-tert-Butylphenoxytetraphenylantimony

2-tert-Butylphenoxytetraphenylantimony Ph₄SbOC₆H₄(Bu-t)-2 was prepared by the reaction of pentaphenylantimony with 2-tert-butylphenol in toluene at 20°. The structure of the obtained compound was determined by X-ray diffraction. The Sb atom in this compound has a distorted trigonal-bipyramidal coordination with the aroxy group in the axial position. The Sb–C(Ph)_eqand Sb–C(Ph)_axdistances are 2.111(7)–2.138(7) and 2.180(7) Å the Sb–O and O–C_Ardistances are 2.143(4) and 1.363(8) Å, respectively. The C(Ph)_axSbO_Araxial angle is 174.1(2)°, while the SbOC angle is 126.7(4)°.     

Simultaneous vibrational relaxation and thermal dissociation of diatomic molecules

A model of a truncated harmonic oscillator with equidistant levels and one-quantum transitions is applied. The balance equations for O₂ have been solved numerically with 26 levels, with the transition probabilities taken as P _k,k +1k exp (k) P ₁₀, in which k is the number of the level and is an adjustable parameter that takes account of the anharmonicity. A Boltzmann distribution is obtained up to level 19 with =0, but for 0 there are deviations from that distribution in lower levels. Levels with k=1, 2, 3 are populated with relaxation times substantially less than the relaxation time for the vibrational energy. Dissociation depletes levels with k 19.     

A New Strategy for the Synthesis of alpha-Difluoromethyl-Substituted alpha-Hydroxy and alpha-Amino Acids

A new method for the preparation of alpha-chlorodifluoromethyl-, alpha-bromodifluoromethyl-, and alpha-difluoromethyl-substituted alpha-hydroxy and alpha-amino acid esters 11, 19-21 is described. The key step of the synthesis is the regioselective alkylation of ketones 5, 7-9 and imines 16-18 with C-nucleophiles. The ketones 7-9 are readily available from 3,3,3-trifluorolactate 1 by a five-step procedure. Subsequent removal of the protecting groups from 19-21 provides the corresponding free amino acids 25, 26, 28.     

Effect of the electronic structure of heteroaromatic compounds on their phototransformations in polar media

The effect of the electronic structure of aromatic (anthracene) and heteroaromatic (phenazine, acridine, 9-methyl-1,2-benzacridine) compounds on the mechanism of the formation of exciplexes with N,N-dimethylaniline and their further transformations in media with various polarities was investigated by the quenching of the fluorescence of the exciplex. It was shown that for heteroaromatic compounds characterized by a substantial contribution from the n^* electronic configuration to the lowest excited singlet state, in contrast to aromatic compounds, the exciplex is formed in two stages, i.e., nonequilibrium Franck-Condon and equilibrium stages. The photodissociation processes for these systems in polar media also take place from a non-equilibrium state. The important role of the steric configuration of the components of the exciplex in its relaxation process was also noticed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 4, pp. 448–454, July–August, 1990.     

[2+4]-Cycloaddition reactions of methyl trifluoropyruvate trifluoroacetylimine

Methyl trifluoropyruvate trifluoroacetylimine (I) reacts regioselectively with olefins to form dihydrooxazines (II)-(VII). In its reactions with 1,3-dienes, too, compound (I) exhibits properties of a 1,3-heterodiene rather than a dienophile. Acid hydrolysis of the synthesized oxazines results in their conversion to substituted -amino--trifluoromethyltetrahydrofuran-2-ones (XII)-(XVI).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1130–1133, May, 1991.     

p-adic zeta functions and Bernoulli numbers

One gives a new proof to the Leopoldt-Kubota-Iwasawa theorem regarding the possibility of the p-adic interpolation of the values of the Riemann zeta-function and of the Dirichlet L-functions at negative integral points. To this end, for each root ? ≠ 1 of unity one introduces and one investigates the numbers C_n(?) which arise in the expansion $$\frac{{\varepsilon - 1}}{{\varepsilon e^z - 1}} = \sum\limits_{n = 0}^\infty {\frac{{C_n (\varepsilon )}}{{n!}}Z^n }$$ One proves a generalization of the Kummer congruences for the Bernoulli numbers.