| Abstract: | The reaction of vinylogs of the Fischer base, viz., 1,3,3-trimethyl-2-(3-methyl-2-buten-1-ylidene) indoline, 1,3,3-trimethyl-2-(2-penten-1-ylidene) indoline, 1,3,3-trimethyl-2-(3-phenyl-2-propen-1-ylidene) indoline, and 1,3,3-trimethyl-2-(2-buten-1-ylidene) indoline, with salicylaldehydes commences with displacement by the aromatic o-hydroxy aldehyde of the vinyl part of the dienamine molecule, as a result of which the usual spirobenzopyran is formed. In the case of the first two dienamines the reaction stops at this stage, whereas in the latter two a second molecule of dienamine adds to the initially formed spirobenzopyran at the double bond of the pyran ring to give  dicondensed spirochromans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 649–653, May, 1981. |
