Synthesis of Perfluoroalkyl[1,2,4]triazolo[1,3]thiazinones

Russian Journal of General Chemistry -     

Research in the pyrimidine series

The frequencies and forms of the normal vibrations of thymine, 5-amino-, 5-fluoro-, 5- and 6-chloro-, 5-bromo-, and 5-nitrouracils and their 1,3-dideutero analogs were calculated, and their force constants were determined. The calculated and observed frequencies were assigned with respect to the types of vibrations. The introduction of substituents into the 5 and 6 positions of the uracil ring leads to a change in a whole series of force constants and to redistribution of the forms of the normal vibrations with respect to natural coordinates. Despite this, one can isolate those structural fragments of the investigated molecules whose normal vibrations remain characteristic in form. A linear dependence of theN₍₁₎H andN₍₃₎H frequencies on the force constants of the corresponding bonds was observed.See [1] for communication XX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 105–113, January, 1975.     

Peculiarities of the growth kinetics of silicon-germanium alloy layers from silane and germane with an additional heated element in the vacuum chamber

To study the disintegration of the molecules of hydrides at the surface of the growing layer and their influence on the rate of the epitaxial process a model of the growth kinetics of Si_1?x Ge_x alloy layers from silane and germane by the molecular beam epitaxy method with SiH₄ and GeH₄ gas sources is considered. Through comparison of numerical simulation data and experimental relationships, the steady-state growth kinetics has been studied and a comparative analysis carried out of the efficiency of entry of Ge(Si) atoms into the growing layer both in the presence of Si and Ge atomic flows in the reactor (the so-called hot-wire method) and in their absence. The growth rates obtained with this method of epitaxial growth and with one of its modifications where the use is made of a sublimating silicon bar as an additional heated element have been compared. Peculiarities in the behavior of the dependence of the layer growth rate on its composition have been revealed and explained.     

Oxo derivatives of 1,3-oxazines (review)

Data on the chemistry of monocyclic oxo-1,3-oxazines with ring multiple bonds for the period 1976 to 1985, inclusively, are correlated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1462, November, 1987.     

New Method of Synthesis of 5-Acyl-1,3-thiazines

Russian Journal of General Chemistry -     

NMR spectrum of poly(propene sulfide)

The 100 MHz spectra of polymers of propene sulfide and propene-2-d₁ sulfide have been determined in CDCl₃, CCl₄, and C₆D₆. In the deuterated polymer the main-chain protons give rise to two overlapping AB quartets in which the two pairs of upfield B lines are coincident and the two pairs of downfield A lines are resolved. With CdCO₃ as polymerization catalyst the downfield quartet is twice as strong as the upfield quartet. The former is ascribed to an isotactic dyad: and the latter to a syndiotactic dyad: Other catalysts (ZnCO₃, CuCO₃, SiO₂/Al₂O₃, Na) produce an essentially atactic structure. The values τ_A = 7.125, τ_A′ = 7.155, τ_B = 7.45, J_AB = ?12.9 Hz, derived from the spectrum of the deuterated polymer (in CCl₄) were used to obtain the following values from the spectrum of the undeuterated polymer (tertiary proton = Hc): τ_C = 7.131, J_BC = 10.0 Hz, J_CA = 4.1 Hz. The magnitudes of the vicinal coupling constants indicate a preferred trans conformation for the mainchain C? C bond. τ_A, τ_B, and τ_C are somewhat dependent on solvent; τCH₃ = 8.63, independent of solvent, and JCH₃, H_C = 6.2 Hz.