Synthesis and reactivity of ethoxyvinyl derivatives of 1,3-dioxolanium salts

2-(-Ethoxyvinyl)dioxolanium salts were obtained by reaction of ortho esters with 2,4,4,5,5-pentamethyl-1,3-dioxolanium perchlorate in acetic anhydride. Alkaline hydrolysis of 2-(-ethoxyvinyl)-4,4,5,5-tetramethyl-1,3-dioxolanium perchlorate leads to the corresponding ,-unsaturated aldehyde. Substituted 2-(-aminovinyl)-1,3-dioxolanium perchlorates are formed by reaction of this salt with aromatic amines, amino acids, and urea. These perchlorates readily split out perchloric acid in alkaline media to give Schiff bases. The charges and electron densities were calculated for the 2-(-methoxyvinyl)-1,3-dioxolanium cation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1614–1617, December, 1973.     

Synthesis and properties of heterocyclic carbonium systems

Bis(4,4,5,5-tetramethyl-2-dioxolano) trimethylidynecyanine was synthesized by condensation of 2-methyl-1,3-dioxolanium perchlorate with 2-formylmethylene-1, 3-dioxolane by heating (90–100C) in acetic anhydride. It is shown that the 1,3-dioxolane also condenses under similar conditions with pyrylium salts containing active methylene and methyl groups to give unsymmetrical dioxolanopyrylocyanines. The synthesized cyanines react with HClO₄ to give unstable diperchlorates, which readily lose a molecule of HClO₄ to give the starting cyanines. Concentrated HCl decomposes one of the dioxolane rings of the symmetrical cyanine, and refluxing with dilute HCl brings about its destruction to low-molecular-weight unidentified compounds. The unsymmetrical cyanine from the pyrylium salt is resistant to the action of acids but is hydrolyzed by alkalis with cleavage of the pyrylium ring to a diketone. The action of Br₂ on the dioxolanocyanine leads to the addition of bromine to the double bonds and replacement of the ClO₄ ^– ion by Br^–.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 595–598, May, 1977.     

Dioxolanium salts

A new method was developed for the synthesis of dioxolanium salts by the condensation of 1,2-glycols of the pinacol series with aliphatic acid anhydrides in the presence of perchloric acid. The dioxolanium ring is opened to form monoacylates of the starting pinacols under the influence of water, alcohol, and ammonia. A method was developed for the acetylation of aromatic compounds by dioxolanium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1023–1026, August, 1971.     

Synthesis of aromatic 4,4,5,5-tetramethyl-1, 3-dioxolanes substituted in position 2 and their salts

A method for the synthesis of 2-aryl-4,4,5,5-tetrainethyl-1,3-dioxolanium salts from cyclic acetals has been developed. The IR spectra of the compounds obtained are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 891–893, July, 1973.     

Synthesis of 2-(3,3-Dicyano-2-propenylidene)-4,4,5,5-tetramethyldioxolane and Its Reactions with Hydrazine and Primary Amines

Reactions of 2-(-ethoxyvinyl)-4,4,5,5-tetramethyl-4,5-dihydro-1,3-dioxol-1-ium salts with cyanomethylene compounds gave the corresponding 2-(2-propenylidene)-1,3-dioxolane derivatives which reacted with hydrazine and primary amines to afford, respectively, 3-(2-hydroxy-1,1,2-trimethylpropoxy)pyrazole and 1-substituted 6-amino-5-cyanopyridin-2(1H)-ones.     

Synthesis and properties of 1,3-dioxolanium salts (review)

Methods for the synthesis of 1,3-dioxolanium salts — a new class of carboxonium cations that are finding application in organic synthesis — and their structure and properties are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 869–882, July, 1975.     

Preparation of 1,3-dioxanium perchlorates

2,4,4,6,6-Substituted 1,3-dioxanium perchlorates were obtained by acylation of ditertiary 1,3-diols with carboxylic acid anhydrides in the presence of 70% perchloric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 169–172, February, 1976.