Mono- and dimethine dyes from 2-dimethylamino-5-formylfurans,-thiophenes,and -selenophenes

The chromaticity of diverse mono- and dimethine dyes obtained from 2-dimethyl-amino-5-formylfurans, -thiophenes, and -selenophenes was examined by means of the Kiprianov-Brooker deviation method. It is shown that the heterocyclic rings have considerably higher basicity than the 4-dimethylaniline ring, that the 2-dimethylamino-5-furan ring is the most basic ring, and that the 2-dimethyl-amino-5-thiophene ring is the least basic ring, whereas the analogous ring of the selenophene occupies an intermediate position that is closer to the thiophene ring.