PURPOSE: To increase the yields of pyridone azo dyes, by reacting formaldehyde with a reaction soln. contg. 1,4-dimethyl-3-cyano-6-hydroxypyrid-2-one and reacting the resulting mixture with a diazotized product of an amine.
CONSTITUTION: A cyanoacetate ester, an acetoacetate ester and a monomethylamine are reacted together to obtain a reaction soln. contg. 1,4-dimethyl-3-cyano- 6-hydroxypyrid-2-one. This soln. is reacted with formaldehyde in the presence of water in a quantity of 1W8 times by weight that of 1,4-dimethyl-3-cyano-6- hydroxypyrid-2-one. The resulting mixture consisting of 1,4-dimethyl-3-cyano-5- hydroxymethyl-6-hydroxypyrid-2-one and 1,4-dimethyl-3-cyano-5-methylene-pyridine-2,6-dione is separated and reacted with a diazotized product of an amine of formula I to obtain the desired pyridone azo dye of formula II.
HIMENO KIYOSHI
TAKIMOTO HIROSHI
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