Synthesis of 2,3-diaryl-1,4-diazolyl-2,3-epoxybutanes

2,3-Diaryl-1,4-diazolyl-2,3-epoxybutanes have been prepared from dimethylstilbenes. An efficient although neglected synthesis of the required olefins has been recovered from the literature. The target compounds show moderate antifungal activity.     

Reaction of 3-methyl-2,3-epoxysulfolane with alcohols

The corresponding dialkyl ethers of 3-methylsulfolane-2,3-diol are formed by the action of alcohols (methanol, ethanol, n-propyl alcohol, isopropyl alcohol, isobutyl alcohol, and n-octyl alcohol) on 3-methyl-2,3-epoxysulfolane in an acidic medium. The reaction proceeds through the intermediate formation of monoethers with subsequent etherification of the hydroxyl group by a second molecule of alcohol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 613–615, May, 1979.     

Reactions of 1-halo-3-methyl-2,3-epoxybutane with alcohols

The reaction of 1-bromo(or chloro)-3-methyl-2,3-epoxybutane with alcohols in the presence of the alkali metal alkoxides leads to the formation of epoxy ethers by direct replacement of the halogen atoms without participation of the epoxide ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 878–880, July, 1981.     

Stereospecific thermal isomerization of 2, 2-dimethylbenzocyclobutenols to 2-isopropenylphenyl alcohols

Thermolysis of the 1-alkyl-2,2-dimethylbenzocyclobutenol 3 at 160 degrees C gave the 2-isopropenylphenyl alcohol 8 through an (E)-dienol intermediate by a 1,5-sigmatropic hydrogen shift from the isopropylidene methyl group to the carbon bearing hydroxy group. In the thermolysis of each of the diastereomeric 2, 2-dimethylbenzocyclobutenols 6 and 7 which have a hydroxy group on the beta-carbon of the quaternary C(1)-alkyl substituent, the isomerization to the 2-isopropenylphenyl alcohols 10 and 11 took place stereospecifically through a twisted (E)-dienol intermediate. The configuration of the newly formed chiral center in 10 and 11 was the same as that of the ring carbon bearing hydroxy group in the starting 6 and 7.     

Hydration of allenylacetylenic alcohols — New route to 6-methyl-2,3-dihydro-4-pyranones

The mercuric sulfate-catalyzed acidic hydration of allenylacetylenic alcohols leads to 6-methyl-2,3-dihydro-4-pyranones — products of cyclization of unsaturated -diketones. In the case of 1-(3,4-pentadien-1-ynyl)cyclohexanol 2-(1-cyclohexenyl)-5-methylfuran is formed in addition to the corresponding dihydropyranone.Communication 113 from the series Reactions of unsaturated compounds. See [1] for communication 112.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 619–622, May, 1984.     

Thermal isomerization of 2-ethyl-3-bromotetrahydrofuran

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, p. 2896, December, 1991.     

Base-catalyzed stereoselective isomerization of electron-deficient propargylic alcohols to E-enones

We have developed highly stereoselective methods to isomerize electron-deficient propargylic alcohols to E-enones under mild conditions (EWG = electron-withdrawing group). Among weak bases we screened, catalytic (10-20 mol %) 1,4-diazabicyclo[2.2.2]octane (DABCO) was found to be effective in most cases. When the substrate is conjugated with an amide, the addition of sodium acetate catalyzed the isomerization.     

Mass spectral fragmentation patterns of 2-methyl-, 2,3-methyl-, 2,3-dimethyl-, 2-aryl- and 3-phenylindole derivatives

The electron impact mass spectrometric fragmentation pathways for several 2-methyl-, 3-methyl-, 2,3-dimethyl-, 2-aryl- and 3-phenylindole derivatives were investigated. An interesting relationship between the substitution pattern in the framework of the indole derivatives and the fragmentation patterns was observed.     

Cp2TiCl-promoted isomerization of trisubstituted epoxides to exo-methylene allylic alcohols on carvone derivatives

The ring-opening reaction of trisubstituted epoxides promoted by Cp2TiCl led to exo-methylene allylic alcohols as major compounds when 0.5 M solutions of the epoxides were added to 0.1 M solutions of the reagent at room temperature in THF. In most cases, the allylic alcohols were contaminated with saturated alcohols. Normal and reverse addition modes led to the alternate product being favored. The different stereochemical outcome of cis- and trans-epoxy acetates is rationalized in terms of mechanistically biased elimination processes.     

The isomerization of optically-active propargyl alcohols to terminal acetylenes.

The isomerization of optically-active secondary propargyl alcohols, RCHOHCC(CH₂)_nCH₃, to terminal acetylenic alcohols, RCHOH(CH₂)_n+1 C=CH, by potassium 3-aminopropylamide (KAPA) proceeds without loss of configuration at the hydroxy center.     

Ring-opening isomerization polymerization of 2-methyl-2-oxazoline initiated by charge transfer complexes

The possibility of opening cyclic iminoethers and forming linear polymers or copolymers under the action of charge transfer complexes has been studied. The polymerization of 2-methyl-2-oxazoline, acting as donor, proceeds in the presence of various organic electron-acceptors such as tetracyanoethylene 7,7,8,8-tetracyanoquinodimethane and 2,4,7-trinitrofluorenone. Initiation takes place by charge transfer complexes formed between the monomer and the acceptor. With acceptors which possess polymerizable bonds, i.e. tetracyanoethylene and tetracyanoquinodimethane, copolymers are obtained.     

Conformational isomerization of 4-methyl-1,3-dioxane

The whole possible course of conformational isomerization of 4-methyl-1,3-dioxane has been established using empirical (MM+) and nonempirical [STO-3G, 3-21G, 6-31G(d) and 6-31G(d,p)] approximations within the limits of the Hartree-Fock method. It was shown that the potential energy surface of this compound contains a principal (equatorial chair conformer) and local minima corresponding to the axial chair conformer and series flexible forms.     

2-p-Chlorphenyl-3-methyl-2,3-butandiol (Phenaglycodol)

Ohne Zusammenfassung     

Zur Bestimmung von 2-p-Chlorphenyl-3-methyl-2,3-butandiol

Ohne Zusammenfassung     

Infrared spectra and rotational isomerization of 1-bromo-3-methyl-2-butene

Infrared spectra obtained for the title compound, (CH₃)₂CCH. CH₂Br, have revealed the co-existence of two rotational isomeric forms in the fluid phases, the geometrical structures of which cannot be ascertained by use of vibrational spectroscopy alone. The energy ditterence between the two isomers was found to be 1.1 kcal mol⁻¹ (mean value) in the liquid state. Some of the i.r. fundamental bands were assigned using the characteristic absorption frequencies of localized group.     

The process of producing 2-methyl-2-butene by positional isomerization on sulfocation exchangers

The results of determination of composition and strength of the granules of nitrogen-phosphoric fertilizers containing 1.5 to 5.0% of P₂O₅, obtained by interaction of the mineralized mass of the phosphorites of Central Kyzylkum with the 70–90% solutions of ammonium nitrate at 110°C, are presented.