Synthesis and x-ray structural analysis of 2-amino-4-cyanomethylene-5,5-dimethylthiazoline

The reaction of thiourea with 4-hydroxy-4-methyl-2-pentynenitrile in triethylamine is accompanied by heterocyclization and the formation of 2-amino-4-cyano-methylene-5, 5-dimethylthiazoline, whose structure was established by x-ray structural analysis (XSA).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2344–2346, October, 1989.     

Simplified calculation of pressure shift and broadening of molecular lines

Gor'kii State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 33, No. 12, pp. 1349–1356, December, 1990     

On the uniqueness of a Haar series that converges with respect to subsequences of partial sums

We prove the existence of two different series in the Haar system for which the subsequences of partial sums converge to the same D-integrable function everywhere on [0, 1].Translated from Matematicheskie Zametki, Vol. 4, No. 6, pp. 707–714, December, 1968.     

Hydrosilylation of Siloxanes in the Presence of Pt(II) and Pt(IV) Complexes

The catalytic activities of Pt(II) and Pt(IV) complexes with various ligands and counterions in hydrosilylation of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane with 1,1,3,3-tetramethyldisiloxanes are compared.     

Competing reactions of hydrophenylation and phenylation in tetraphenylantimony chloride methyl acrylate palladium chloride system

A new catalytic reaction of the competing phenylation and hydrophenylation in air of methyl acrylate with tetraphenylantimony chloride in the presence of PdCl₂ (0.04 mol per 1 mol of organometallic compound) in acetonitrile at 50°C for 6 h was studied. The yields of methyl cynnamate and methyl hydrocynnamate were 0.73 and 0.27 mol mol^?1 respectively. The products ratio obtained depends slightly on the process duration, the Ph₄SbCl and methyl acrylate ratio, and the structure of Pd salt [PdCl₂, Pd(OAc)₂, Li₂PdCl₄], but significantly on the nature of a solvent (MeCN > DMF > THF). The use of Ph₄SbCl instead of Ph₄SbBr leads to decrease in the yield of methyl hydrocynnamate to 0.04 mol mol^?1. In the reactions of Ph₄SbX (X = F, I, OAc, O₂CEt) the product is not formed at all.     

Specific Features of Catalytic Hydrosilylation in Siloxane Systems in the Presence of Sulfoxide-Containing Platinum(II) Complexes

The rate of addition of MeSiH(OSiMe₃)₂, Me₂SiHOSiMe₃, and (Me₂SiH)₂O to vinylsiloxanes ViMeSi(OSiMe₃)₂, ViMe₂SiOSiMe₃, and (ViMe₂Si)₂O in the presence of square-planar platinum complexes [Pt(LL')X₂] (where L and L' are neutral ligands, and X is an anionic ligand) decreases in the following series of L and L': Ph₃PS > MeS(O)Tol-p > MeCOD > CH₂ÍCH₂ COD > Et₂SO > Et₂S > Me₂SO 2-aminopyridine > Py > 2-methylpyridine. Variation of X, the ligands L and L' remaining unchanged, leads to decrease in the reaction rate in the series: C₂O₄ ^{2 -} > NO₃ ^- > Cl^- Br^-. Mixed-ligand complexes like (-)-[Pt(MeSOTol-p)PyCl₂] having a cis structure are more efficient catalysts then the corresponding trans isomers in the hydrosilylation of siloxanes. Reactions of sulfoxide platinum(II) complexes with vinylsiloxanes and silicon hydrides result in isomerization of the metal complex and dissociation of the sulfoxide; bis-sulfoxide complexes undergo deoxygenation of the sulfoxide ligand with formation of colloidal platinum. It was presumed that the active form of the catalyst is its trans isomer; it reacts with silicon hydride, leading to replacement of the sulfoxide ligand in the inner sphere of platinum(II) complex. The reactivity of silicon hydrides toward vinylsiloxanes in the presence of sulfoxide platinum(II) complexes decreases in the series (Me₂SiH)₂O > Me₂SiHOSiMe₃ > MeHSi(OSiMe₃)₂, and the vinylsiloxanes form the following reactivity series: ViMe₂SiOSiMe₃ > ViMeSi(OSiMe₃)₂ > (ViSiMe₂)₂O. These series conform to increase of the positive charge on the silicon atom and decrease in steric hindrance created by the substituents thereon.     

A study of the reaction mechanism of the catalytic intramolecular conversion of heterocycles

In order to study the reaction mechanism of the catalytic intramolecular conversion of heterocycles [1–3] and to broaden the field of their application, we have studied the dehydration over Al₂O₃ of 1-amino-3-(-tetrahydrofuryl) propane (I), 1-methylamino-1-(-tetrahydrofuryl) propane (II), and 2-(3-hydroxy-1-propyl)-1-methylpyrrolidine (III), leading in all three cases to pyrrolizidine (IV).