Aminoanthraquinone pigments

The term polycyclic pigments refers to pigments which are derived from the an-thraquinone skeleton, either by chemical structure or by synthesis. The complex fused-ring systems which are discussed in this context are all at least remotely related to the parent anthraquinone structure. 

This chapter classifies polycyclic pigments by chemical constitution. The resulting classes include aminoanthraquinones, hydroxyanthraquinones, heterocyclic and polycarbocyclic anthraquinone pigments. 

With the exception of the anthraquinone-azo series and the salts of hydrox-yanthraquinone sulfonic acids, all of the listed compounds have known a long history as vat dyes before their pigment properties gained commercial recognition (Sec. 3.3). 

As a group, these pigments include derivatives of 1-aminoanthraquinone, which is the only derivative of the possible parent compounds which has stimulated commercial interest. While the synthetic routes to the pigment derivatives are found under the respective pigments, the pathway for 1-aminoanthraquinone will be described separately. 

The traditionally most important route to 1-aminoanthraquinone [1] proceeds via nucleophilic exchange of anthraquinone-1-sulfonic acid or 1-chloroanthraquinone with ammonia. Replacing ammonia by amines affords the corresponding alkyl or arylaminoanthraquinones. 

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P.R.264 provides bluish red shades, which are similar to those of P.R.177, an aminoanthraquinone pigment. The fastness properties are similar to the other types of the DPP pigment class. The commercially available grade is distinguished... 

Polycyclic amines, such as a-aminoanthraquinone, and heterocyclic amines, such as aminophthalimide, aminobenzazoles, or aminoquinazolines are less interesting coupling components for azo pigments. 

Aminoanthraquinone is diazotized advantageously with nitrosylsulfuric acid after being dissolved in sulfuric acid. Coupling the diazo compound onto barbituric acid, for instance, affords a yellow pigment [3] with the structure 79 ... 

Coupling 1-aminoanthraquinone with certain Naphthol AS derivatives produces red pigments [4] with the structure 80, which are suitable colorants for plastics ... 

Other anthraquinone/azo pigments are obtained by coupling 1-aminoanthraquinone derivatives onto bis-quinazolinone methanes with the following chemical structure 82 ... 

As a class, these pigments include 1-aminoanthraquinone compounds which bear free amino groups, and also derivatives in which the primary amino group is substituted by an aryl or a heteroaryl moiety. Only very few representatives are industrially important. 

The most important route to 1-acylaminoanthraquinones involves reaction of 1-aminoanthraquinone with acid chlorides in an organic solvent. Reaction of 1-aminoanthraquinone with benzoylchloride in nitrobenzene at 100 to 150°C affords 1-benzoylaminoanthraquinone, a yellow pigment which is registered as Colour Index Constitution No. 60515. The reaction may also be performed in the presence of a tertiary amine, which acts as a proton acceptor ... 

Condensation of 1-aminoanthraquinone with phthalic acid chloride in o-dichlorobenzene at 145°C also yields a yellow pigment, registered as Pigment Yellow 123,65049 [9] ... 

Among heterocyclic substituted 1-aminoanthraquinone derivatives, the 2 1 reaction product with 1-phenyl-2,4,6-triazine, also referred to as Pigment Yellow 147,60645, should be mentioned as an example [10]. It is a reddish yellow pigment with the chemical structure 87 ... 

Pigment Yellow 147[76168-75-7] is derived from reaction of 1-aminoanthraquinone with l-phenyl-3,5-dichloro-2,4,6-triazine. It is a reddish shade yellow pigment used primarily in certain plastics and in polyester and polypropylene fibers. 

Indanthrone. Pigment Blue 60 [81-77-6] is synthesized by oxidative dimerization of 2-aminoanthraquinone in the presence of a strong base, and then particle size reduced by precipitation from very strong sulfuric acid or by milling. The very red-shade blue pigment shows outstanding weatherfastness in full shade as well as in light white reductions. It is used primarily in metallized automotive finishes where it is sometimes more weatherfast than copper phthalocyanine blue. 

The anthrapyrimidine sub-group of the polycyclic pigments are heterocyclic anthraquinones. 1,9-anthrapyrimidme, which is not used commercially, is the parent structure for this group this, and its substituted derivatives, are obtained by condensation of 1-aminoanthraquinone. The principal member is anthrapyrimidine yellow. Cl 68420/Pigment Yellow 108 Colour Index, 1971), a compound mainly used in paints (Herbst and Hunger, 1997). 

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