Azines and azoles: CXXIX. Synthesis,structure, and some reactions of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-ones

Reactions of 2-aryl-4-chloro-6H-1,3-thiazin-6-ones with sodium sulfide in aqueous alcohol at 18–20°C led to the formation of a readily separable mixture of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-one sodium salts (yield >70%) and bis(2-aryl-6-oxo-6H-1,3-thiazin-4-yl) sulfides (<10%). The latter can also be obtained in more than 50% yield by treatment of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-one sodium salts with 2-aryl-4-chloro-6H-1,3-thiazin-6-ones. Methylation of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-ones afforded the corresponding methylsulfanyl derivatives (yield >90%) regardless of the alkylating agent, solvent, temperature, reactant concentration, and their ratio. 2-Aryl-4-sulfanyl-6H-1,3-thiazin-6-ones in the crystalline state and in solutions in polar and nonpolar protic and aprotic solvents exist preferentially as 4-sulfanyl-6-oxo tautomers, and they undergo almost complete ionization in neutral aqueous, alcoholic, and aqueous-alcoholic media (pK _a = 4.3). Reactions of 4-sulfanyl-2-phenyl-6H-1,3-thiazin-6-one with ammonia, amines, and difunctional N-centered nucleophiles involve cleavage of the C⁶-S bond in the thiazine ring and subsequent recyclization of linear intermediates to pyrimidines and diazole derivatives. The structure of the isolated compounds was confiirmed by ¹H and ¹³C NMR, IR, and UV spectra.     

Investigations in the series of heterocycles. 53. Mass spectra of 5-arylidenebarbituric acids and their 2-thio- and 2-seleno-analogs

The mass spectra of 5-arylidenebarbituric acids, their 2-thio- and 2-seleno-analogs, barbituric, 2-thio- and 2-selenobarbituric acid, as well as selenourea, were obtained. The molecular ions of these compounds, as a rule, the main ones in intensity, may break down along several pathways, the ratio of which depends substantially on the nature of the atom bound to the carbon atom in the 2-position of the pyrimidine ring. The influence of substituents in the benzene ring on the direction of decomposition of the molecular ions is negligible.For Communication 52, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 974–982, July, 1984.     

Hydroxypyrimidines Condensation with Carbonyl Compounds: II. Hydroxy-, Sulfanyl-, and Aminopyrimidines

The first part of review treated condensation of barbituric acids with carbonyl compounds both in the absence and in the presence of third components [1]. In so doing we discussed only the reactions involving the C ⁵ atom of the pyrimidine ring. The second part concerns similar transformations of other hydroxy- and aminopyrimidines and thioanalogs thereof.     

Azoles and azines: CXXVIII. Reaction of 2-aryl-4-hydroxy-6H-1,3-thiazin-6-ones with 6-bromo-4-oxo-4H-chromene-3-carbaldehyde

Russian Journal of General Chemistry -     

Condensations of thioamides with acetylenecarboxylic acid derivatives

The review summarizes published data on the reactions of cyclic and acyclic thioamides with derivatives of acetylenecarboxylic acids, which lead to the formation of both acyclic and heterocyclic systems, including thiazolidines and thiazines. Methods for determination of the structure of the condensation products and factors responsible for the reaction direction are discussed.     

Computer Simulation of the Destruction of the Organic Lanthanide Complexes under Ionizing Radiation

The calculation of defects in the structures of the Sc, La, Nd, Sm, Tb, and Yb complexes with substituted phenolate and naphtholate ligands formed under the action of neutrons with a mean energy of 2 MeV shows that the shifts of the target atoms depend on their masses and can achieve 1 μm for O, N, and S. A similar result is obtained for the calculation of the destruction of the Eu(TTA)₃(DME)₂ complex (HTTA is thenoyltrifluoroacetone). However, the treatment of the samples with the n,γ radiation does not result in destruction. Possible reasons for the found divergence between the calculated and experimental data are discussed.

     

Effect of atomic silicon and germanium beams on the growth kinetics of Si<Subscript>1 – <Emphasis Type="Italic">x</Emphasis></Subscript>Ge<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> layers in Si–GeH<Subscript>4</Subscript> molecular beam epitaxy

The steady-state kinetics of growth of Si_{1 – x} Ge _x layers in one version of hybrid molecular beam epitaxy with a molecular germane source and a sublimating silicon bar has been studied. It has been demonstrated that the processes of capture of hydride molecule radicals by the epitaxial surface and their subsequent decomposition must be taken into account in the analysis of growth kinetics. The comparison of experimental data with the results of kinetic analysis has revealed a close match between them. At low germane pressures \({P_{Ge{H_4}}}\) < 0.5 mTorr, the nature of the growth process is defined exclusively by the specifics of interaction between the molecular beam of Ge monohydride with the growth surface. The influence of the atomic Ge beam from the Si source only manifests at germane pressures exceeding 1 mTorr. Under these conditions, the fluxes of Ge and Si atoms from the sublimating Si source become equal, and the concentration of germyl molecules on the surface reaches saturation. The observed increase in the \({V_{Ge{H_3}}}\) parameter is associated with the activating influence of the flux of silicon atoms from the sublimating source on the decomposition of molecules.