Irgashev, R. A. An approach to the construction of benzofuran-thieno[3,2- b]indole-cored N,O,S-heteroacenes using fischer indolization / R. A. Irgashev, N. A. Kazin, G. L. Rusinov // ACS omega. - 2021. - Vol. 6, № 47. - P32277-32284 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: A series of 6H-benzofuro[2′,3′:4,5]thieno[3,2-b]indoles were readily synthesized from methyl 3-aminothieno[3,2-b]benzofuran-2-carboxylates using a one-pot procedure with Fischer indolization as the key step. At the same time, 3-aminothieno[3,2-b]benzofuran-2-carboxylates were prepared from 3-chlorobenzofuran-2-carbaldehydes in three steps, including replacement of the Cl atom at the C-3 position of these starting substrates onto the -SCH2CO2Me moiety, conversion of the CHO group at the C-2 position into the CN group, followed by base-promoted cyclization of the formed carbonitrile. The present route was elaborated by us because we failed to obtain directly the desired 3-aminothiophene-2-carboxylate by reaction of 3-chlorobenzofuran-2-carbonitrile with methyl thioglycolate in the presence of various bases. In turn, 3-chlorobenzofuran-2-carbaldehydes were prepared from benzofuran-3(2H)-ones following the Vilsmeier–Haack–Arnold reaction. |