Structure of 4-nitro-3-benzoyloxy-1,1-dimethyl-1-silacyclopentane in liquid and solid phases

Conclusions By means of¹³C and¹H NMR using a lanthanide shift reagent, along with x-ray structure analysis, a structural study has been made of 4-nitro-3-benzoyloxy-1,1-dimethyl-1-silacyclopentane; and it has been shown that the five-membered organosilicon heterocycle in the liquid and solid phases has the half-chair conformation with predominantly diequatorial orientation of the substituents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1773–1777, August, 1987.The authors wish to thank A. G. Kozlovskii for participating in this work.     

Thermal and photochemical isomerization of exocyclic 1,3-dienes: 1,1-diphenyl-3,4-bis(trimethylsilylmethylene)-1-silacyclopentane s-cis(E,E)

This paper describes the photochemical and the thermal isomerization of s-cis(E,E) 1,1-diphenly-3,4-bis(trimethylsilylmethylene)-1-silacyclopentane (1a). Under thermal conditions a 1,3-sigmatropic of the methylene hydrogen occurs, yielding the s-trans isomer (1b). The photochemical irradiation of (1a) at 300 nm for 1 h in deoxygenated benzene gives the corresponding s-cis(E,Z) isomer (1c) and then the s-cis(Z,Z) isomer (1d) after prolonged irradiation (3 h). There was no evidence for the formation of the corresponding cyclobutene resulting from the ring closure of the exocylic diene.     

Crystal structure analysis of 3,4-dimethyl-2,5-dihydrothiophen-1,1-dioxide

The geometry of 3,4-dimethyl-2,5-dihydrothiophen-1,1-dioxide was determined by X-ray diffraction: cell dimensions are reported together with bond lengths and bond angles. While bond lengths are smaller than those for the homologue 3-methyl-2,5-dihydrothiophen-1,1-dioxide, bond angles are similar. TheMe-C₃-C₄-Me torsion angle is 5.1±0.5°. These results are consistent with its relatively slow rate of decomposition.

---

Kristallstrukturanalyse von 3,4-Dimethyl-2,5-dihydrothiophen-1,1-dioxid

Zusammenfassung Die Geometrie von 3,4-Dimethyl-2,5-dihydrothiophen-1,1-dioxid wurde mittels Röntgendiffraktion bestimmt. Es werden die Dimensionen der Einheitszelle zusammen mit Bindungslängen und Bindungswinkeln berichtet. Die Bindungswinkel sind sehr ähnlich denen des homologen 3-Methyl-2,5-dihydrothiophen-1,1-dioxids, die Bindungslängen sind jedoch kürzer. DerMe-C 3-C 4-Me Torsionswinkel ist 5.1±0.5°. Diese Ergebnisse sind mit der relativ langsamen Zersetzungsgeschwindigkeit im Einklang.

     

Production and hydrolysis of 3,4-dimethyl-2,5-diphenyl-1,3-oxazolidine

Summary Condensation of ephedrine with benzaldehyde, an acid catalyzed reversible reaction, producing 3,4-dimethyl-2,5-diphenyl-1,3-oxazolidine, was studied. If the starting reaction mixture contained acetic acid, it quantitatively reacted with ephedrine and produced a salt functioning as an acid catalyst. On the contrary, ephedrine hydrochloride had no catalytic effect.     

Hydrolysis of 3,4-diphenyl-1,2,5-thiadiazole-1,1-dioxide. Acid and base catalysis

We have performed a product and kinetic study of the hydrolysis of 3,4-diphenyl-1,2,5-thiadiazole-1,1-dioxide in aqueous solution. Benzil and sulfamide are the only products of hydrolysis and are formed in equimolar yields. The kinetic results indicate that a first order law is followed up to 90% conversion. The observed rate constant is independent of substrate concentration. Ionic strength and buffer concentration do not affect the rate constant, but the reaction is acid-base catalyzed. The rate-pH profile has been determined and a mechanism that fits the experimental data satisfactorily is proposed. Corresponding rate constants and equilibrium constants for the protonation of the substrate are reported.     

Spectroscopic studies of 1,2-diphenyl-3,3,4,4-tetramethylcyclobutene and 3,4-diphenyl-2,5-dimethyl-2,4-hexadiene radical cations and their possible interconversion

In order to study radical cation rearrangements, the species generated by γ-irradiation of 1,2-diphenyl-3,3,4, 4-tetramethylcyclobutene (CB) and 3,4-diphenyl-2,5-dimethyl-2,4-hexadiene (BD) in frozen Freon solutions were studied by monitoring their EPR and visible absorption spectra. The optical and EPR spectra are indicative of CB⁺ and BD⁺ Conversion of CB⁺ to BD⁺ is not a dominant process at low temperatures in CFCl₃ or the Freon mixture (50:50 CFCl₃:CF₂BrCF₂Br) but can be assisted photochemically.     

Synthesis and configuration of 4-alkyl-2-methyl-3,4-diphenyl-1,2-thiazetidine 1,1-dioxide

4-Alkyl-2-methyl-3,4-diphenyl-1,2-thiazetidine 1,1-dioxide 5, 6 and 7 were obtained from 2-methyl-3,4-diphenyl-1,2-thiazetidine 1,1-dioxide 1 by reaction of its anion 4 with alkyl halides. cis- and trans-Configuration of the 4-alkylated products were determined by ¹H-nmr and NOE difference spectro-scopy studies.     

Colloid-chemical properties of 1,1-dimethyl-1-alkylhydrazinium chlorides

The colloid-chemical properties [surface tension, surface activity, and critical micellization concentration (CMC)] of aqueous 1,1-dimethyl-1-alkyl(R)hydrazinium chlorides (R = C₁₀H₂₁–C₁₈H₃₇) were studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 11, 2004, pp. 1861–1864.Original Russian Text Copyright © 2004 by Shcherban, Radushev, Nasretdinova, Teterina, Bubyakina.     

Physicochemical properties of 1,1-dimethyl-1-alkylhydrazinium chlorides

With the aim of widening the applications of 1,1-dimethyl-1-alkylhydrazinium chlorides, the physicochemical properties (solubility, hygroscopicity, thermal and chemical stability, distribution between aqueous and organic phases) of their homologs with the alkyl radicals C₁₀H₂₁-C₁₈H₃₇ were studied.     

Cycloadditions of 3,4-dimethyl-1-thio-1-phenyl phosphole

Phosphole sulfide 1 undergoes cycloaddition to give a new 15-phosphasteroid. The ¹³C-NMR and ²J_PC-coupling constants of several compounds prepared similarly are discussed, permitting structure assignment to one of the 7-phosphabicyclo[2.2.1]heptane adduct 5. Thiophosgene reacts with the PS moiety of 1, giving 12 after hydrolysis, through a PS to PO transformation coupled in case of 1 with a proton migration.     

Reaction of 2,5-diphenyl-3,4-diazacyclopentadien-1-one 3,4-dioxide with trialkyl phosphites

Conclusions The trimethyl and triethyl phosphite react with 2,5-diphenyl-3,4-diazacyclopentadien-1-one 3,4-dioxide to give 1-alkyl-3,5-diphenyl-4-pyrazolyl dialkyl phosphates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1422–1424, June, 1972.