Synthesis of unsaturated organoselenium compounds via the reaction of organic diselenides with 2,3-dichloro-1-propene in the hydrazine hydrate-KOH system

Dimethyldiselenide reacts with 2,3-dichloro-1-propene at 20–25°C in the hydrazine hydrate-KOH medium to form 2-chloro-3-methylselanyl-1-propene with 90% yield. Diphenyldiselenide in the reaction with 2,3-dichloro-1-propene, depending on the conditions, can give quite selectively four products: 2-chloro-3-phenylselanyl-1-propene, phenylselanylpropadiene, 1-phenylselanyl-1-propyne, and Z-1,2-bis(phenylselanyl)-1-propene. The effect of the selenium atom on the reaction direction and the products structure is discussed.     

Specific features of the reactions of 2,3-dichloro-1-propene with dibenzylchalcogenides in the system hydrazine hydrate-alkali

Dibenzyldisulfide and -diselenide react with 2,3-dichloro-1-propene in the system hydrazine hydrate-KOH by the domino mechanism: nucleophilic substitution of the allyl chlorine, dehydrochlorination with participation of the chlorine atom at the sp ²-carbon atom, allene-acetylene rearrangement, nucleophilic addition of the chalcogenide reagent to the triple bond. The effect of the nature of the chalcogen atom and the benzyl substituent on the studied domino reaction is discussed.     

Reaction of diphenyl ditelluride with 2,3-dichloroprop-1-ene in the system hydrazine hydrate-KOH

Diphenyl ditelluride reacts with 2,3-dichloroprop-1-ene in the system hydrazine hydrate-KOH along several parallel routes. Beside the nucleophilic chlorine substitution at the sp ³-hybridized carbon atom resulting in 2-chloro-3-phenyltellanylprop-1-ene the elimination of both chlorine atoms occurs affording a mixture of allene and methylacetylene. The reasons of the dual elimination reaction paths are considered.     

N-allenylation of pyrroles by 2,3-dichloro-1-propene

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, p. 125, January, 1992.     

Reaction of 1,3- and 2,3-dichloroprop-1-enes with dipotassium propane-1,3-ditellurolate in the system hydrazine hydrate-KOH

Russian Journal of Organic Chemistry -     

Reactions of chloromethyl heptyl ether with selenium and tellurium in the system hydrazine hydrate-potassium hydroxide

Chloromethyl heptyl ether reacts with selenium in the system hydrazine hydrate-potassium hydroxide with formation of a mixture of bis(heptyloxymethyl)selane (32%) and bis(heptyloxymethyl)diselane (64%). Reductive cleavage of the latter with hydrazine hydrate-KOH and subsequent alkylation with methyl iodide gave methyl(heptyloxymethyl)selane in 94% yield. Analogous reaction of tellurium with hydrazine hydrate-KOH leads to the formation of extremely unstable bis(heptyloxymethyl)ditellane and bis(heptyloxymethyl) tellane at a ratio of 1: 4.     

Molecular structure and conformation of 2,3-dichloro-1-propene as determined by gas-phase electron diffraction

The molecular structure and conformation of 2,3-dichloro-1-propene have been determined by gas-phase electron diffraction at nozzle temperatures of 24, 90 and 273°C. The molecules exist as a mixture of two conformers with the chlorine atoms anti (torsion angle ∠φ = 0°) or gauche (∠φ = 109°) to each other and with the anti form the more stable. The composition (mole fraction) of the vapor with uncertainties estimated at 2σ was found to be 0.55 (0.08), 0.49 (0.08) and 0.41 (0.10) at 24, 90 and 273°, respectively. These values correspond to an energy difference with estimated standard deviation ΔE° = E°_g-E°_a = 0.7 ± 0.3 kcal mol^?1 and an entropy difference ΔS° = S°_g-S°_a = 0.6 ± 0.9 cal mol^?1 K^?1. Some of the diffraction results, together with spectroscopic observations, permit the evaluation of an approximate torsional potential function of the form 2V = V₁ (1 - cos φ) + V₂ (1 - cos 2φ) + V₃ (1 - cos 3φ); the results are V₁ = 4.4 ± 0.5, V₂ = ?2.9 ± 0.5 and V₃ = 4.8 ± 0.2, all in kcal mol^?1. The results at 24°C for the distance (r_a) and angle (∠_α) parameters, with estimated uncertainties of 2σ, are: r(C_sp²-H) = 1.098(0.020)Å, r(C_sp³-H) = 1.103(0.020)Å, r(CC) = 1.334(0.009)Å, r(C-C) = 1.504(0.013)Å, r(C_sp²-Cl) = 1.752(0.021)Å, r(C_sp³-Cl) = 1.776(0.020)Å, ∠C-CC = 127.6(1.1)°, ∠C_sp³-C_sp²-Cl = 110.2(1.0), ∠C_sp²-C_sp³-Cl = 113.1(1.2)°, ∠H-C_sp³-H = 109.5° (assumed), ∠CC-H = 120.0° (assumed) and ∠φ = 108.9(3.4)°.     

Reaction of tellurium with dichloromethane in the system hydrazine hydrate-alkali

Tellurium reacts with dichloromethane in the system hydrazine hydrate-alkali substituting one chlorine atom by tellurium whereas the second chlorine atom undergoes reductive substitution by hydrogen leading to the formation of methyltellanyl derivatives. Tentative mechanism of reduction is discussed. The discovered reaction allows the preparation of organotellurium compounds containing the MeTe group, including those involving other chalcogens.     

Simple one-pot synthesis of 5-(chloromethyl)isoxazoles from aldoximes and 2,3-dichloro-1-propene

Chemistry of Heterocyclic Compounds - A one-pot synthesis of 3-substituted 5-chloromethylisoxazoles from available starting aldoximes and 2,3-dichloro-1-propene, serving both as a solvent and...     

Reaction of 1,1-dichloroethane with tellurium in the system hydrazine hydrate-potassium hydroxide

The reaction of 1,1-dichloroethane with tellurium in the system hydrazine hydrate-potassium hydroxide gave ethyltellanyl derivatives as a result of replacement of one chlorine atom in the substrate by tellurium, and of the other, by hydrogen. Probable mechanisms of reduction of the C-Cl bond and mass spectra of the products were considered. The mass spectra of ditelluroacetals revealed unusual rearrangement of the molecular ion, leading to the formation of Te-Te and new C-C bond.     

Reactions of siliranes with elemental sulfur and with t-butyl mercaptan. Preparation of the 2,3-dithia-1-silacyclopentane ring system

The reaction of 1,1-dimethyl-trans-2,3,-bis(2′,2′-dimethylcyclopropylidene)-1-silirane with S₈ gives a mixture of four isomeric products derived from incorporation of one sulfur atom and a cyclopropylcarbinyl-to-butenyl type rearrangement. This silirane reacts with t-butyl mercaptan to give a product of mercaptan addition in which a cyclopropylcarbinyl-to-butenyl rearrangement also has occurred. Hexamethylsilirane reacts with S₈ to give 1,1,4,4,5,5-hexamethyl-2,3-dithia-1-silacyclopentane in high yield. These reactions are discussed in terms of free radical mechanisms.     

Conformations and vibrational spectra of 2,3-dichloro and 2,3-dibromo-1-propene

The infrared spectra of 2,3-dichloro- and 2,3-dibromo-1-propene in the region 4000-200 cm^?1 were recorded of the liquids and of the crystalline solids at ?180 °C. Raman spectra, including semiquantitative polarization measurements were obtained of the liquids. Additional spectra were recorded of the samples dissolved in polar and non-polar solvents and of unannealed as well as of annealed crystalline solids at ?180 °C.Approximately 13 vibrational bands present in the spectra of the liquids and solutions as well as of the amorphous solid vanished in the crystal spectra. From the intensity variations with changing solvent polarity it was concluded that the conformer present in the crystal was more polar (gauche) than the other, simultaneously present in the liquid (cis). A striking similarity between the spectra of the two compounds was observed. All the fundamentals for the gauche conformers have tentatively been assigned.     

Domino reaction of 2,3-dichloroprop-1-ene with diphenyl disulfide in the system hydrazine hydrate-potassium hydroxide

2,3-Dichloroprop-1-ene reacted with diphenyl disulfide in the system hydrazine hydrate-potassium hydroxide at 30–35°C to give three products: 2-chloro-3-phenylsulfanylprop-1-ene, 1-phenylsulfanylpropadiene, and 1-phenylsulfanylprop-1-yne. Variation of temperature ensures selective synthesis of one of the above products, which confirms their successive formation (domino reaction). The domino reaction at 60°C goes further to afford (Z)-1,2-bis(phenylsulfanyl)prop-1-ene.     

Reactions of dichloromethane with chalcogens and dimethyl chalcogenides in the hydrazine hydrate-alkali system

Methods of synthesis of compounds MeY(CH₂Y) _n Me (Y=S, Se, Te; n = 1–3) containing several identical or different chalcogen atoms are suggested. The methods are based on the reactions of dichloromethane with elemental chalcogens (Y^2?) and dimethyl dichalcogenides (MeY^?) activated in the system hydrazine hydrate-alkali. The effect of the chalcogen on the reactivity toward dichloromethane is qualitatively assessed. With elemental tellurium in the system hydrazine hydrate-alkali, reduction of one chlorine atom in dichloromethane and formation of methyltellanyl derivatives are observed.     

Reactions ofβ-chloroethyl derivatives of tricoordinated phosphorus acids with 1-nitro-1-propene

Conclusions The reactions of the-chloroethyl derivatives of trivalent phosphorus acids proceed via an ionic intermediate, which, depending on the experimental conditions, is stabilized in the direction of ring closure to give an adduct with a pentacovalent phosphorus atom and the formation of the corresponding unsaturated and (-methyl--nitroethyl)phosphoryl compounds. The liberated-chloroethyl nitrite functions as an oxidizing agent of the starting-chloroethyl derivatives of trivalent phosphorus acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1398–1401, June, 1978.The authors thank É. I. Gol'dfarb for taking the³¹P–{¹H} NMDR spectra.