E. A. Viktorova

Pummerer reaction in synthesis and transformations of heterocyclic compounds (review)

Data on the use of the Pummerer reaction in the synthesis and transformations of various heterocyclic compounds that contain oxygen, sulfur, and nitrogen as the heteroatoms are correlated.

Thio-claisen rearrangement in the synthesis of sulfur-containing heterocyclic compounds (review)

The review is devoted to literature information on the mechanism of the thio-Claisen rearrangement of allyl aryl (heteryl) sulfides and their use in the synthesis of five- and six-membered sulfur-containing heterocyclic compounds, including derivatives of dihydrobenzothiophene and thiochromane.

Isomerization of oxygen-containing heterocycles in the presence of activated charcoal

Alky1-2,3-dihydrobenzofurans, octahydrobenzofuran, and chromans undergo skeletal isomerization, dehydroisomerization, cis-trans isomerization, and dehydrogenation in the presence of BAU-activated charcoal. An ionic mechanism including initial stripping of a hydride ion from the starting compounds is proposed for the reactions. It is shown by means of ESR spectroscopy that there is no correlation between the catalyst activity and the concentration of paramagnetic centers on it. It is assumed that quinoid groupings on the charcoal surface are the active centers.

Formation of benzothia crowns in reaction of the diallyl derivative of 2-mercapto-4-methylphenol with SCl2

The reaction of SCl2 with 1-altyloxy-2-allylthio-4-methylbenzene gave a mixture of 2,9,11,18-tetra-chloromethyldi(4-methylbenzo)-1,7,10,13-tetrathia-18-crown-6 and 2,9,11,18-tetrachloromethyldi-(4-methylbenzo)-1,7,10,15-tetrathia-18-crown-6.

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides in the synthesis of 2,3-dihydronaphtho- and naphtho[1,2-b]thiophenes

Abstract2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides, obtained by thermolysis of alkyl 1-naphthyl sulfoxides, are reduced by lithium aluminum hydride to 2,3-dihydronaphtho [1,2-b]thiophenes, whereas under the influence of acetic and trifluoroacetic anhydrides they form naphtho[1,2-b]thiophenes.

Retention of optical activity in the [3,3]-sigmatropic rearrangement of a vinyl furfuryl ether

Abstract(−)-1-(2-Furyl)ethyl 2-propenyl ether undergoes a [3,3]-sigmatropic rearrangement with the formation of (+)-2-(2-ethyl-3-furyl)propanol, which indicates an at least partially concerted reaction mechanism.

Formation of uncondensed binuclear heterocyclic compounds in the thio-claisen rearrangement of heteroaromatic sulfides

Allyl hetaryl Sulfides with an allyl fragment that is part of a heteroaromatic ring undergo a [3,3]-sigmatropic rearrangement when they are heated in various solvents, as a result of which uncondensed binuclear heterocyclic compounds are formed. On the basis of kinetic data it was shown that the inclusion of the vinyl or allyl fragment of a sulfide in the composition of the heteroaromatic ring hinders the rearrangement more, the higher the aromatic character of the heteroring.

Sigmatropic rearrangements of alkenyl benzofuryl and benzothienyl sulfides

The thio Claisen rearrangement of 2-butenyl 2-benzofuryl sulfide, cyclopenten-2-yl 2-benzofuryl sulfide, 2-butenyl 2-benzothienyl sulfide, and cyclopenten-2-yl 2-benzothienyl sulfide was investigated. The rates, energies and entropies of activation of the process were calculated, and the effect of the structure of the sulfide, the polarity of the solvent, and the temperature was demonstrated by comparison of these values. The 1,3-thioallyl rearrangement of 1-methylallyl 3-methyl-2-benzothienyl sulfide was studied, and it was shown that this reaction competes with the thio Claisen rearrangement.

[3,3]-Sigmatropic rearrangement of chloro-substituted allyl thienyl sulfides

The kinetics of the rearrangement of allyl 5-chloro-2-thienyl sulfide and β-chloroallyl 2-thienyl sulfide to, respectively, 5-chloro-3-allyl-2-thiophenethiol and 3-(β-chloroallyl)-2-thiophenethiol were investigated. It is shown that an acceptor substituent in the allyl group decreases the reactivity of the sulfide significantly, whereas an acceptor in the heterocyclic ring does not have an appreciable effect on it.

Electronic absorption spectra and acidities of heteroaromatic thiols

The electronic absorption spectra of a number of substituted and unsubstituted thiophene-, benzothiophene-, and benzofuranthiols were studied, and their ionization constants were determined by establishment of the dependence of the optical densities of aqueous alcohol solutions of them on the pH.