Syntheses with Nitriles, LXIX. Isomeric Diamino Alkoxy Pyridine Carbonitriles-Separation and Application as Coupling Components

Article abstract of DOI:10.1007/BF00799957

The isomeric 4,6-diamino-2-alkoxy- (3), and 2,4-diamino-6-alkoxy-3-pyridine-carbonitriles (4) are obtained by treatment of 2-amino-1,1,3-tricyanopropene (1) with sodium alkoxides.Separation is based on their different pK_α-values (3a = 2.01, 4a = 4.17).Coupling reaction of 3a-c with benzenediazonium chloride in strong acidic medium leads to the yellow azo dyes 5a-c, whereas coupling of 4a requires a buffered solution (pH 4-6) to yield 6.The UV-VIS spectra of the isomer pyridines and the azo dyes are discussed. - keywords: Azo Dyes; Diamino-alkoxy-pyridine-carbonitriles; UV-VIS spectra