Syntheses with Nitriles, LXXIII. Ether Cleavage of Pyridines with Unusual Halogenation to Isomeric Diamino-pyridone-carbonitriles and Their Application as Coupling Components

Article abstract of DOI:10.1007/BF00811253

Ether cleavage of the two isomeric diamino-methoxy-pyridine-carbonitriles 1 and 2 leads to the isomeric 4,6-diamino-2(1H)-pyridone-3-carbonitrile (3a) and 2,4-diamino-6(1H)-pyridone-3-carbonitrile (4a), resp.Dependent on the reaction conditions in glacial acetic acid containing hydrogen bromide or potassium iodide the halogenated pyridones (3b,4b-c) can be obtained. pK_s-values and UV-spectra of the pyridones are discussed. 3a and 4a can be used as azo-coupling components, yielding the azo-dyes 5 and 6.Similarly 4-amino-6-hydroxy-2(1H)-pyridones (7a-b) are coupled with several aryl- and heteroaryl-diazoniumsalts to form the azo-dyes 8a-g. - Keywords: 4,6-Diamino-2(1H)-pyridone-3-carbonitrile; 2,4-Diamino-6(1H)-pyridone-3-carbonitrile; Bromination and iodination; Azo-dyes