Among condensed aromatic compounds which can provide conjugated polyene system and have absorption in the electron band, 2-naphthol derivatives are relatively inexpensive and are employed widely in the industrial field. For example, 2-naphthol derivatives are used for manufacturing coloring materials such as dyes and pigments, photosensitive materials and polymer materials such as liquid crystalline polymers.
Among various 2-naphthol derivatives, 2-hydroxynaphthoic acid derivatives wherein the carboxylic acid group is converted to aminocarbonyl or ureidocarbonyl group are especially useful as coupler component for manufacturing azo pigments.
For manufacturing amidated 2-hydroxynaphthoic acid derivative, there are several industrially applicable efficient methods; for example, it can be obtained by reacting corresponding acid halogenated compound and an amine. For manufacturing 2-hydroxy-ureidocarbonyl naphthalene derivative, there is a proposed method which contains the step of reacting acid chloride of the 2-hydroxynaphthalene-3,6-dicarboxylic acid and urea derivative to give the 3,6-di-ureidocarbonyl derivative (see U.S. Pat. No. 6,252,104, the contents is herein incorporated by reference). However said method is not suitable for industrial synthesize since it takes quite a long time and provides only a low yield.
USPTO Backgrounds
USPTO Backgrounds