V. Yu. Mortikov

Condensed heterocycles. 44. Synthesis and structure of imines of 2-mercaptobenzo[b]-furan-3-carbaldehydes and 3-mercaptobenzo[b]furan-2-carbaldehydes and their derivatives

A number of isomeric mercapto aldimines of benzo[b]furan have been obtained and their structure and properties have been studied in comparison with their benzo[b]-thiophene analogs. It has been shown that the nature of the heterocycle has no substantial influence on the structure and properties of these compounds, in contrast to the initial mercapto and hydroseleno aldehydes. It has been observed that the 2-mercapto or 2-methylthio(methylseleno) groups in benzo[b]furan-3-carbaldehydes are readily replaced by an amino group, while they are not replaced in the isomeric 3-mercapto- and 3-methylthio(methylseleno)benzo[b]furan-2-cabaldehydes.

Condensed heterocycles. 40. The structure of 2- and 3-benzo[b]thiophenaldehydes and their imines containing a hydrosulfide or hydroselenide group in the adjacent position

The structure of isomeric selenol(mercapto)aldimines of benzo[b]thiophene and the complexes formed by them was studied by the methods of IR, UV, and ESR spectroscopy and magnetic susceptibility. The influence of the structure of the exocycylic heteroatom on the structure of 2- and 3-benzo[b]thiophenaldehydes containing OH, SH, or SeH groups in the adjacent position, in contrast to their imines, was demonstrated. An analogous change in the nature of the exocyclic heteroatom in complex compounds of selenol(mercapto)aldimines also does not lead to any change in the flat structure of the coordination unit in these complexes.

Condensed heterocycles. 42. Synthesis and some properties of 3-hydroselenobenzo[b]furan-2-carbaldehyde and 2-hydroselenobenzo[b]furan-3-carbaldehyde

The reactions of 3-chlorobenzo[b]furan-2-carbaldehyde and 2-bromobenzo[b]furan-3-carbaldehyde with sodium hydrogen selenide have yielded isomeric hydroseleno aldehydes which, under the action of atmospheric oxygen, have oxidized to diselenides, while alkylation of the seleno aldehydes with methyl iodide leads to the formation of the corresponding methylseleno derivatives.

Condensed heterocycles. 41. Mass spectrometric study of selenol(mercapto)aldimines of benzo[b]thiophene and their S, Se-alkyl derivatives

The production of imines of 3-selenol(mercapto)-2-benzo[b]thiophenaldehyde and 2-selenol(mercapto)-3-benzo[b]thiophenaldehyde and their S,Se-alkyl derivatives under electron impact was studied. The main distinctions of the decomposition of the molecular ions of selenium-containing compounds from their sulfur analogs, due to the greater strength of the C-S bond in comparison with the C-Se bond, were demonstrated. The different behavior of isomeric 3- and 2-mercaptoaldimines of benzo[b]thiophene was detected.

Condensed heteroaromatic systems that include a thiophene ring

New complexing compounds, viz., 2-formylbenzo[b]thiophene-3-selenol and 3-formylbenzo[b]-thiophene-2-selenol, and some derivatives involving the selenium atom and the formyl group, as well as complexes of divalent nickel and copper based on them, were obtained. The tautomerism of the isomeric formylthiopheneselenols was studied by means of IR spectroscopy, and it was shown that 3-formylbenzo[b]thiophene-2-selenol, in contrast to 2-formylbenzo[b]thiophene-3-selenol, exists in the form of a mixture of two tautomers.