Diene Condensation of Cyclopentadiene with Dienophiles of Allylacetylene Series

Diene condensation of cyclopentadiene with 2-substituted allylacetylenes occurs nonselectively at a double and triple bonds; therewith the dienophile activity grows in parallel with the electron-withdrawing properties of the substituent. Depending on electronic character of functional groups the reaction proceeds as neutral diene synthesis. The relative activity of cyclopentadiene and 1,3-cyclohexadiene in reactions with allylacetylenes is essentially governed by the different distance between the 1,4-reactive sites in these systems.     

Synthesis and Some Chemical Transformations of Unsaturated Ketones of the Dihydropyran Series

Russian Journal of Organic Chemistry - Methods have been developed for the synthesis of unsaturated ketones of the dihydropyran series via aldolization-crotonization of...     

Allylacetylenes and their derivatives as inhibitors of steel corrosion in sulfuric acid

New functionalized derivatives of allylacetylenes were prepared, and their ability to inhibit corrosion of St.3 low-carbon steel in 5 N sulfuric acid was studied. The effectiveness of inhibition of steel corrosion was studied in relation to the structure of acetylene derivatives, their concentration, and temperature of acidic medium.     

Hypohalogenation of vinyl- and allylacetylenes and some chemical transformations of the products

Hypohalogenation of 2-methylhex-5-en-3-yn-2-ol, 2-methylhept-6-en-3-yn-2-ol, and their methyl ethers at 303–328 K with hydrochloric or hydrobromic acid in the presence of hydrogen peroxide involves only the double bond to produce the corresponding halohydrins in fairly high yields. Kinetic parameters of these reactions were determined, and the allylacetylenic alcohol and its methyl ether were found to be more reactive than their vinylacetylenic analogs. Acetylenic halohydrins and oxiranes derived therefrom were shown to be quite reactive compounds which may be used as building blocks in organic synthesis.     

Synthesis diacetylenic ethers with terminal acetylenic bonds and studying them as inhibitors of steel corrosion in hydrochloric acid

New diacetylenic ethers with terminal acetylenic bonds were synthesized.     

Synthesis and some chemical conversions of acetylenic derivatives of 1,4-dioxane

The possibility has been shown of synthesizing acetylenic derivatives of 1,4-dioxane in high yield by the interaction of glycidyl ethers of acetylenic alcohols with ethylene bromohydrin in the presence of boron trifluoride etherate. Dehydrobromination of the corresponding bromohydrin was then carried out in the presence of metallic sodium in absolute diethyl ether. Acetylenic derivatives of 1,4-dioxane enter into hydrosilylation, aminomethylation, and diene condensation reactions with the formation of new derivatives of 1,4-dioxane.     

Diene Condensation of Polychlorocyclic Dienes with Dienophiles of Allylacetylene Series

Diene condensations of hexachlorocyclopentadiene and 5,5-dimethoxytetrachlorocyclopentadiene were carried out with dienophiles of allylacetylene series. The reaction was demonstrated to proceed stereospecifically yielding adducts of the endo-configuration. The reactivity of functionalized allylacetylene compounds in the diene synthesis with hexachlorocyclopentadiene was studied, and the reaction was established to occur by the type of a neutral diene synthesis. It was established that the Faworsky decomposition of polychlorobicyclic alcohols containing in the side chain a triple bond adjacent to a methylene group occurred with acetylene-allene isomerization.     

Use of Chemical and Microbiological Methods to Synthesize Natural Polyacetylenes

Chemistry of Natural Compounds - Chemical and microbiological methods for synthesizing polyacetylenes were studied. The reaction of 1,4-dibromobutyne with monosubstituted acetylene alcohols...     

Hypohalogenation of functionally substituted acetylenic norbornenes

Hypohalogenation of norbornenes containing a triple bond and various functional groups in the side chain was performed using mixtures of aqueous solutions of hydrochloric or hydrobromic acid (or sodium or potassium bromide) and hydrogen peroxide. The reaction was found to involve addition of electrophilic reagent generated in situ (HOBr or HOCl) at the endocyclic double bond with formation of the corresponding halohydrins. The latter underwent dehydrohalogenation by the action of alklai to give exo-5,6-epoxybicyclo[2.2.1]-heptane derivatives in high yields. Kinetic relations holding in the hypobromination process were established, and the initial rates and activation parameters were calculated.     

Synthesis and modification of ED-20 epoxy-4,4′-isopropylidenediphenol resin with highly unsaturated esters

Esters of the dienyne series with a trans-ethylene bond were prepared in 70–80% yield by reactions of enyne aldehydes with ethoxycarbonylmethylenetriphenylphosphorane. The compounds were studied by IR and ¹H NMR spectroscopy, and their modifying effect on ED-20 epoxy-4,4′-isopropyl-idenediphenol resin was revealed.