Rearrangement reactions of the molecular ions of some substituted aliphatic oxiranes

The fragmentation reactions of glycidic methyl ester (1) and of its derivatives (2–6) substituted by one, two and three methyl groups, respectively, at the oxirane ring, of the corresponding glycidols (7–12), and of the glycidyl ethers (13–16) in the 70 eV mass spectra have been studied using isotopic labelling and mass-analysed ion kinetic energy spectrometry. It is shown that the typical reaction of these aliphatic oxirane radical cations carrying a nucleophilic methoxy group and hydroxy group, respectively, at the side chain corresponds under high-energy conditions to a rearrangement by a methoxy group or a hydroxy group migration to the β-carbon atom of the oxirane moiety. This rearrangement is very likely mediated by the isomerization of the molecular ions into distonic ions via C? C bond cleavage within the oxirane ring.     

Spatial structures of substituted oxiranes

Conclusions On the basis of the measurements of dipole moments and Kerr constants it can be said that the oxides of the thiophene chalcone analogues exist in s-cis and s-trans conformations, these differing in the mutual orientation of oxirane ring and carbonyl group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1514–1518, July, 1976.The authors wish to thank V. I. Savin for having supplied the thienyl cyclopropyl ketone(IX).     

The geometrical structures of the substituted oxiranes

Conclusions The oxiranecarbaldehydes exist as single conformers in solution. The carbonyl group is rotated out of the plane of the bisector of the oxide ring by some 40°, the carbonyl-group oxygen being thereby separated from the oxide-ring oxygen. This conformation is favored from the standpoint of dipole-dipole interactions.Translated from Izvestiya Akademii Nauk SSSR, Sariya Khimicheskaya, No. 6, pp. 1257–1260, June, 1979.The authors would like to thank V. N. Zinin who prepared the PMR spectra.     

1H NMR spectra of oxiranes. cis-Arylmethyl oxiranes substituted in the phenyl ring

The ¹H NMR parameters for a number of cis-arylmethyl oxiranes are reported and discussed in comparison with those of trans derivatives and styrene oxides substituted in the phenyl ring. While the macroscopic behaviour of the results is in agreement with a perturbative mechanism through the oxirane ring that is mainly electrostatic in character, a small contribution due to conjugative interaction is not excluded. It seems likely that the effect of substituents in the phenyl ring is mainly transmitted through bonds rather than through space, and that the different polarisation of the C? H bonds in the oxirane ring is mainly responsible for the different behaviour of the protons in cis- and trans- arylmethyl oxiranes towards the effect of substituents.     

MG-FSGO calculation of ethane geometry and rotation barrier

MG-FSGO calculations on ethane have been performed employing a moderately large basis set with complete orbital plus geometry optimization. A nearly exact result for the rotation barrier is obtained, but the computed geometry is poor.     

Geometrical structures of the substituted oxiranes. 7. The conformations of the nitrooxiranes

Conclusions The NO₂ groups of trans-2-methyl- and trans-2-trichloromethylnitrooxirane exist in bisector conformations.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, Wo, 8, pp. 1761–1763, August, 1979.     

The dynamics of the thermal decomposition of norbornenone

The thermal decomposition of norbornenone has been investigated in the temperature range 650–2200 K at pressures between 1 and 1000 Torr using a shock tube and a cw CO laser. The kinetics approach first order for pressures above 250 Torr and the high-pressure activation energy for the decomposition is 124 ± 6 kJ mole⁻¹. Measurements made above 900 K show that the CO is born preferentially in the υ = 0 state and subsequently relaxes to the Boltzmann vibrational distribution appropriate to the translational temperature. These results provide information on the dynamics of the dissociation process.     

Synthesis and reactions of some substituted 1, 3, 5-triazines

The reactions of 2-substituted 4, 6-dihydroxytriazines with PCl₅ and SOCl₂ are investigated. It is shown that conversion of 2-(aryl- and substituted styryl)-4, 6-dihydroxy-1, 3, 5-triazine to the corresponding 4, 6-dichloro compounds is accompanied by ring opening and, in the case of styryl derivatives, by chlorination of the ethylene group. Analysis of the IR spectra of 4, 6-dihydroxytriazines establishes that under ordinary conditions they are 4, 6-dihydroxytetrahydrotriazines. Shift of the lactim-lactam equilibrium towards the oxo form is considered to be the reason why these compounds react with difficulty with SOCl₂. A mechanism for the reaction of triazine hydroxy derivatives with PCl₅ is put forward. New substituted triazines and intermediates are synthesized.     

Spectroscopic calculation of CH bond dissociation energy in the series of chloro derivatives of methane, ethane, and propane

The bond-dissociation energy of CH bonds in chloro derivatives of methane, ethane, and propane has been determined by spectroscopic and quantum chemical methods. Spectroscopic values for CH bond dissociation energy were computed, basing on fundamental absorption bands in the anharmonic approximation, by the variational method with the use of the Morse anharmonic basis. Quantum chemical computations were performed using the basis 6-311G(3df, 3pd)/B3LYP. There are discussed the obtained regularities of changes in the bond dissociation energy when the structure of a molecule is changed.     

Radical polymerization of vinyl monomers initiated by a mono-captodatively substituted ethane

Homopolymerization of styrene and methyl methacrylate was carried out at 60–130°C in the presence of a mono-captodatively (cd) substituted ethane bearing nitrile and ethylsulfenyl substituents on the same carbon atom. It was found that the cd-ethane accelerated both styrene and methyl methacrylate polymerizations with no induction period, but the polymerization mode of methyl methacrylate was different from that of styrene. The polymerization rate of styrene was proportional to the 0.46th power of the cd-ethane concentration. However, the cd-ethane produced a reversible radical termination in the case of methyl methacrylate. The mechanism of both polymerizations is discussed in terms of the kinetic and ESR data. © 1996 John Wiley & Sons, Inc.     

Schemes of calculation of the properties of substituted ethylenes

Calculation schemes for estimation of the properties of X-substituted ethylenes based on the concept of atoms interacting in pairs are described. The equivalence of these schemes are shown, and the relations between their parameters are established.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2586–2587, October, 1996.     

Syntheses of some substituted sym-triazines

The synthesis of various -substituted propionimidic esters has been effected and the conditions of their conversion into the corresponding 2,4,6-triethyl-sym-triazine derivatives have been studied.     

Synthesis of some substituted pyridylsydnones

Synthesis of the I-oxide ( 2 ) of the photochromic N-(3-pyridyl) sydnone ( 1 ), of N-(5-bromo-3-pyridyl) sydnone ( 3 ), and the I-oxide ( 4 ) of 3 were undertaken in order to study the effect on photochromism exerted by substituents on the pyridine ring. Compounds 2 and 3 were prepared via the corresponding aminopyridines and N-pyridylglycines by the general procedure used earlier to prepare 1 . The required amines, 3-aminopyridine I-oxide and 3-amino-5-bromopyridine, were obtained by Hofmann rearrangement of the corresponding amides. An excellent preparation of 5-bromonicotinamide was developed involving bromination in thionyl chloride followed by reaction of the bromoacid chloride with ammonia in chloroform. Proof of structure for 2 and 3 was accomplished by acid hydrolysis to the corresponding hydrazines, which were isolated, respectively, as acetophenone 3-pyridylhydrazone I-oxide and as 5-bromo-3-pyridylhydrazine hydrochloride. These products were identical with samples prepared by reduction of the respective diazotized amines. Sydnone 4 eluded preparation by this general procedure. 3-Amino-5-bromopyridine I-oxide was prepared conveniently from 5-bromonicotinamide but attempts to prepare the corresponding glycine by catalytic hydrogenation of a mixture of the amine and butyl glyoxylate afforded, in acid solution, N-(3-pyridyl)glycine and, in neutral or alkaline solution, the I-oxide of N-(3-pyridyl)glycine. Both products resulted from the reductive cleavage of the bromine atom. Neither 2 nor 3 was photochromic.