Vibrational analysis of halogenated derivatives of cyclobuten-3,4-ione-II. 1-Chloro-2-iodo-, 1-bromo-2-iodo- and 1,2-diiodocyclobuten-3,4-dione

The FTIR spectrum has been measured for the new compounds 1-chloro-2-iodo-, 1-bromo-2-iodo- and 1,2-diiodocyclobuten-3,4-dione in solution and as iso-oriented polycrystalline films in polarized radiation. Utilizing the corresponding vibrational assignment, and the results of a previous investigation, we propose a planar force field for all six 1,2-dihalogenocyclobuten-3,4-diones not containing fluorine.     

Heterocyclization of 2-chloro-1-cyano-1-diethoxyphosphoryl-2-trifluoromethylethylene and 2-chloro-2-chlorodifluoromethyl-1-cyano-1-diethoxyphosphorylethylene

The reactions of 2-chloro-1-cyano-1-diethoxyphosphoryl-2-trifluoromethylethylene (2a) and 2-chloro-2-chlorodifluoromethyl-1-cyano-1-diethoxyphosphorylethylene (2b) with arylamines, arylhydrazines, amidines, 2-aminopyridines, and 5-aminopyrazoles were studied. Alkenes 2a, b can serve as precursors of aminopyrazoles, pyrimidines, pyrido[1,2-a]pyrimidines, and pyrazolo[1,5-a]pyrimidines modified with the fluoroalkyl and diethoxyphosphoryl groups. Intermediates of some heterocyclization reactions were detected by NMR spectroscopy. The structures of the compounds were confirmed by X ray diffraction analysis.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1977–1986, September, 2004.     

Vibrational analysis of alkyl iodides: 1-iodo-2- methylpropane and 1-iodo-3-methylbutane

Liquid and solid-state infrared spectra were obtained for 1-iodo-2-methylpropane and 1-iodo-3-methylbutane. The C-I stretching bands of the P_C and P_H' conformers of the propane were observed at 601 and 582 cm^?1, respectively, and those of the P_C and P_H conformers of the butane were observed at 595 and 512 cm^?1. Both conformers of each compound are present in the amorphous solid. Only the more sterically hindered P_H' conformer is present in the crystalline solid of the propane, and only the P_H conformer is present in the crystals of the butane. Vibrational assignments were made for both conformers of each compound with the aid of normal coordinate calculations. The increase in C-I stretching frequency of the P_H' conformer of the propane from the normal value in alkyi iodides (from ca. 500 to 582 cm^?1) is attributed to the increased contribution of C-C stretch and decreased contribution of C-I stretch.     

Preparation of 6-chloro-6-desoxy- and 6-iodo-6-desoxycellulose

Conclusions The reaction of 2,3-di-O-acetylcellulose with N-chloro- or N-iodosuccinimide and triphenylphosphine gave the 6-chloro-6-desoxy- and 6-iodo-6-desoxycellulose acetates with a respective degree of substitution (DS) in halogen of 0.8–1.0 and 0.7. The deacetylation of these compounds gave 6-chloro-6-desoxycellulose (DS 0.8) and 6-iodo-6-desoxycellulose (DS 0.6).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2158–2160, September, 1977.     

Synthesis of n-(2-chloro-5-bromo-4-pyrimidyl)- and N-(2-chloro-5-iodo-4-pyrimidyl)amino acids

The previously unreported N-(2-chloro-5-bromo-4-pyrimidyl)- and N-(2-chloro-5-iodo-4-pyrimidyl) amino acids were synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 527–529, April, 1971.     

Vibrational spectra of 1-chloro-2-methylpropane and 1-chloro-2,2-dimethylpropane

Infrared and Raman spectra are obtained for 1-chloro-2-methylpropane and 1-chloro-2,2-dimethylpropane. The former compound exists as a mixture of P_C and P_H' conformers in the liquid and unannealed solid states, but only the P_C conformer is present in the crystalline solid. Vibrational assignments are made for both conformers of 1-chloro-2-methylpropane and for 1-chloro-2,2-dimethylpropane with the aid of normal coordinate calculations.     

Thiylating effect of 2-chloro-2-thiono-5-methyl-1,2-oxaphospholane

It was found that 2-chloro-2-thiono-5-methyl-1,2-oxaphospholane has a thiylating effect toward some compounds with carbonyl and phosphoryl groups.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1605–1606, July, 1991.     

Copper(II) complexes of 2-chloro- and 2-bromo 1,3,4-thiadiazoles

Summary A series of copper(II) complexes of 2-X-1,3,4-thiadiazoles, of the types Cu(XL)_1.5X₂, Cu(XL)₂X₂ and Cu(XL)_4– (ClO₄)₂ · nH₂O (X = Cl or Br) has been investigated by electronic, infrared and e.p.r. spectroscopies, thermal analyses (TG and DTG) and magnetic moment measurements. The complexes have tetragonal or square pyramidal stereochemistry with CuN₄X₂ (X = Cl, Br or O) and CuN₃Cl₂ chromophores, respectively.     

Substituted propanes: V. The vibrational spectra,dipole moments and conformations of 1,2-dichloro-, 1-chloro-2-bromo- and 1,2-dibromopropane

The infrared and Raman spectra of 1,2-dichloro-, 1-chloro-2-bromo- and 1,2-dibromopropane were recorded as liquids, in polar and non-polar solvents and in the crystalline state at low temperatures. The infrared spectrum of a high pressure crystal of 1,2-dibromopropane was recorded at ambient temperature. Dipole measurements were carried out in CCl₄ and C₆H₆solutions.Each of the 1,2-dihalopropanes existed as a mixture of three conformers in the liquid state, the one with the halogens in the anti position was in large abundance. Spectral and dipole measurements revealed a comparatively larger concentration of the two polar gauche conformers in polar solvents. All the compounds crystallized in the anti form. The C-halogen stretching vibrations have been interpreted in detail. Vibrational analyses of the anti conformers have been carried out and a tentative assignment of the majority of the gauche bands has been proposed.     

Vibrational analysis of halogenated derivatives of cyclobuten-3,4-dione I. 1,2-Dichloro-, 1-chloro-2-bromo-, and 1,2-dibromocyclobuten-3,4-dione

The polarized Raman spectrum of solutions, and the infra-red spectra of solutions and isooriented films in polarized radiation have been measured for 1,2-dichloro- and for the previously unknown 1-chloro-2-bromo- and 1,2 dibromocyclobuten-3,4-dione. A normal coordinate analysis has been carried out with the aims of obtaining an acceptably low dispersion force field and a good agreement with the experimental frequencies.     

New 4-pentafluorosulfanyl and 4-perfluoroalkylthio derivatives of 1-chloro-2-nitro- and 1-chloro-2,6-dinitrobenzenes

New 4-pentafluorosulfanyl and 4-perfluoroalkylthio derivatives of 1-chloro-2-nitrobenzene and 1-chloro-2,6-dinitrobenzene were prepared from the corresponding bis(4-chloro-3-nitrophenyl)disulfide and bis(4-chloro-3,5-dinitrophenyl)disulfide, respectively. The SF₅ derivatives were obtained by fluorination of the disulfides with AgF₂ according to Sheppard’s method, while perfluoroalkylation was carried out by means of thermolytic reactions with xenon(II) bis(perfluoroalkylcarboxylates). The introduction of fluorine-containing, electron-withdrawing substituents into the aromatic ring (in the presence of other deactivating groups) reinforces the activation of the halogen substituent towards nucleophilic attack. Several nucleophilic substitution reactions have been carried out with these compounds, and as a result, some N- and S-containing groups were introduced in the benzene ring. For example, the previously unknown SF₅, CF₃S, and C₂F₅S analogues of trifluralin (Treflan^®) were prepared and characterized. Additional synthetic possibilities for heterocyclic chemistry are presented on the basis of reactions of the new 1-chloro-2,6-dinitrobenzene derivatives with ethyl thioglycolate wherein fluorine-containing derivatives of benzothiazole N-oxide were obtained as the main products.     

Base pair stability of 8-chloro- and 8-iodo-2'-deoxyguanosine opposite 2'-deoxycytidine: implications regarding the bioactivity of 8-oxo-2'-deoxyguanosine

8-Oxo-2'-deoxyguanosine (OdG) is an abundant and promutagenic damaged nucleotide that has been linked to aging and disease. To gain insight into the alternate base pairings of OdG, 8-chloro- and 8-iodo-2'-deoxyguanosine were incorporated into oligonucleotides and, along with 2'-deoxyguanosine and 8-bromo-2'-deoxyguanosine, were tested for their stability in base pairs opposite dC. We found a strong correlation between increased atomic radius and bond length at C8 and decreased base pair stability. These findings along with NMR studies on the base conformation of the corresponding nucleosides support the theory that the steric bulk of the 8-oxygen plays a role in OdG mutation and disease.     

Transformations of 3-aryl-2-chloro-2-imidoylaziridines: novel entries to 4-chloro-2,5-diaryl-1H-imidazoles and 2-chloro-2-acylaziridines

The reactivity of stereochemically defined 3-aryl-2-chloro-2-imidoylaziridines, an unexplored class of substituted aziridines, was investigated under various reaction conditions. 2-Chloro-2-imidoylaziridines underwent a novel thermal rearrangement by reflux in acetonitrile via C-C bond cleavage to 4-chloro-2,5-diarylimidazoles in high yield. Alternatively, a novel efficient entry toward 2-aroyl-2-chloroaziridines was based on the chemoselective hydrolysis of 2-chloro-2-imidoylaziridines with hydrochloric acid in aqueous tetrahydrofuran.