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.For communication 43, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 598–602, May, 1985.     

Synthesis of heterocyclic compounds from 4-formylpyrazoles

Formylation of pyrazole and 2,5-dimethylpyrazole gave a number of pyrazole-containing aldehydes, which can be used to obtain chromenes, tetrahydrochromenes, 1,4-dihydropyrano[2,3-c]pyrazoles, pyrano[3,2-c]chromenes, thiochromeno[4,3-b]pyrans, pyrano[3,2-c]-quinolines, and thiazolo[3,2-a]pyridines.     

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.See [1] for communication 35.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 898–904, July, 1979.     

Structure of 4-amino-6-phenyl-5-cyano-2-cyclohexanespiro-1,3-dithia-4-cyclohexene and its recyclization to 5,6-tetramethylene-4-phenyl-3-cyano-2[1H]pyridinethione

Conclusions An intramolecular conformationally-rigid conjugation system was found in 4-amino-6-phenyl-5-cyano-2-cyclohexanespiro-1,3-dithia-4-cyclohexene. A probable mechanism for recyclization to the corresponding 2(1H)-pyridinethione was proposed on the basis of the geometrical parameters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1768–1774, August, 1985.     

Condensed heterocycles. 45. Synthesis and structures of imines of 2-selenolo-3-benzo [b] furanaldehyde and 3-selenolo-2-benzo [b] furanaldehyde and their derivatives

A number of new selenolaldimines of benzo [b] furan were synthesized. It was established that they exist in dipolar form with delocalized multiple bonds.See [1] for communication 44.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 774–778, June, 1986.