Contribution A La Connaissance Des Colorants Pyrylo‐Cyanines I.—Pyrylohémicyanines Et Colorants Polyméthiniques Phényl‐ Et Furyl‐pyryliques

A number of condensation products from 1, 2, 3, 4-tetrahydroxanthylium tetrachloroferrate with polyene aldehydes and from substituted β[4(1, 2, 3, 4-tetrahydroxanthyl)]-acroleins with aromatic amines have been reported and their absorption characteristics described.