| 摘要 |
1,250,071. Disperse azo dyes containing dihydroxypyridine residues. SANDOZ Ltd. 9 Jan., 1969 [18 Jan., 1968], No. 1303/69. Heading C4P. The invention comprises azo dyes, free from SO 3 H groups, of formula wherein R 1 is a diazo component of the benzene or naphthalene series which may be substituted by a phenylazo residue, R 2 is CN or an acyl radical and R 3 is an aryl or heterocyclic radical which may be substituted. The dyes are prepared by diazotizing an amine R 1 -NH 2 and coupling the diazonium compound with an appropriate 6-hydroxypyridone-2 and give yellow shades on synthetic hydrophobic fibres. |
