N. I. Golovanova

Pyrroles from ketoximes and acetylene

Abstract2-(2-Furyl)pyrroles and 1-vinyl-2-(2-furyl)pyrroles were obtained in up to 80% yields in the reaction of ketoximes of the furan series with acetylene in MOH—dimethyl sulfoxide (M = Li, K) Superbase media.

ADDITION OF METHYL MERCAPTOACETATE TO N-VINYLPYRROLES

Methyl esters of 2-(pyrryl-1)ethylthioacetic acid were synthesized in 53–71% yield by addition of methyl mercaptoacetate to N-vinylpyrroles. Their reactions with ammonia and hydrazine hydrate were investigated.

Synthesis of 2-(2-selenienyl)pyrrole from methyl-2-selenienylketoxime and acetylene

The reaction of methyl-2-selenienylketoxime with acetylene in KOH-DMSO gives 2-(2-selenienyl)pyrrole and its 1-vinyl derivative.

Pyrroles from ketoximes and acetylene. 45. A new route to 2,2-dipyrroles

The reaction of 1-methyl-2-acetylpyrrole oxime with acetylene at atmospheric and increased pressure can be catalyzed by KOH-DMSO superbase to give 1-methyl-2-(2-pyrrolyl)pyrrole, N-vinyl-2-[1-methyl(2-pyrrolyl)]pyrrole, and the reaction intermediate methyl-2-(1-methylpyrrolyl)-O-vinyloxime.

Pyrroles from ketoximes and acetylene. No. 36. 4,4,6,6-Tetramethyl-4,5,6,7-tetrahydro-5-azaindole, its nitroxyl and vinyl derivatives, and spin-labelled copolymer

An oxime containing a nitroxyl functional group site, 2,2,6,6-tetramethyl-1-nitroxyl-4-hydroxyiminopiperidine, has been shown for the first time to engage in productive pyrrole synthesis via reaction with acetylene in KOH-DMSO. The behavior of 2,2,6,6-tetramethyl-4-piperidone oxime and its 1-hydroxy derivative in this reaction has also been investigated. The corresponding 5-azaindole and its 5-nitroxyl and 1-vinyl derivatives have been synthesized in this manner. 1-Hydroxy-4-piperidone oxime reacts at 50–60‡C under the general reaction conditions undergoing oxidative conversion to 5-azaindole, while at 105‡C in the presence of excess acetylene reduction of the hydroxy group also takes place. The formation of a pyrrole ring does not involve radical chains, although vinylation of the resulting pyrroles apparently involves one-electron transfer. 1-Vinyl-4,4,6,6-tetramethyl-4,5,6,7-tetrahydro-5-azaindole has been used for the preparation of a spin-labelled polyvinyl alcohol copolymer.

Synthesis of pyrrole-2-carboxylic acids and their N-vinyl derivatives

Haloform cleavage of 2-trifluoroacetyl- and N-vinyl-2-trifluoroacetylpyrroles gives pyrrole-2-carboxylic acids and their N-vinyl derivatives in good yields; most of these compounds do not melt between 120–190‡C, but rather decompose with CO2 evolution.

Synthesis of 1-alkylthio-3H-indolizin-3-ones

We have recently tbund that 2-(t-alkylthio-2-cyanoethenyl)pyrroies are tbrmed in the reaction of ethyt pyrrole-2dithiocarboxylates of the I type with malonodinitrile and cyanoacetamide in the KOH--DMSO system with subsequent alkylation [1]. In attempting to extend this reaction to methylene-active compounds II with an ester grouping we observed that the principal (R = CH) or only pathway in this case is the formation of 1-ethylthio-3H-indolizin-3-ones IVa-c.

TRANSMISSION OF INFLUENCE OF SUBSTITUENT IN 2-ARYLPYRROLE-5-CARBOXYLIC ACIDS

Research on the influence of substituenis on the reaction centers of molecules, through various bridge groups, is still an urgent task in theoretical organic chemistry. This problem is usually solved using the Hammett equation f=ρσ + a, by comparing the coefficient ρ of the particular series of compounds under investigation with the coefficient ρ0 of a reference series of compounds. The ratio of coefficients ρ/ρ0=π′, which is called the transmission factor, characterizes structural changes of the bridge group [1, 2].

Reaction of pyrroles with carbon disulfide in KOH/DMSO system

By the interaction of pyrroles with carbon disulfide and haloalkanes in a KOH/DMSO system, esters of 1- and 2-pyrrolyldithiocarboxylic acids have been synthesized. The influence of substituents on the direction of the reaction has been established.

Pyrroles from ketoximes and acetylene. 40. Reaction of alkyl hetaryl ketoximes with 1,2-dichloroethane in superbase media

Abstract2-(2-Furyl)- and 2-(2-thienyl)pyrroles and their N-vinyl derivatives were synthesized by the reaction of alkyl furyl (thienyl) ketoximes with 1,2-dichloroethane in superbase media. 2-Chloroethyl and vinyl ethers of alkyl hetaryl ketoximes are intermediates in the reaction.