Provided is, for example, a compound excellent in light fastness and storage stability. The compound is characterized by having a structure represented by the following formula (1) or (2).

##STR00001##

The subject of the present invention is symmetric or dissymetric azomethine direct dyes comprising at least one pyrazolopyridine unit of formula (I), a composition comprising said dyes, a process for treating keratin fibers using said dyes, a process for preparing these compounds, synthesis intermediates and a kit. In which formula (I) X, Y.sub.1, Y.sub.2, Z.sub.1, and R.sub.1 to R.sub.5 are as defined in the description.

##STR00001##

Disclosed are an optical filter including a near infrared absorption layer on a polymer film. The polymer film has a* of about 5.0 to about +5.0 and b* of about 5.0 to about +5.0 in a color coordinate expressed by a CIE Lab color space. The near infrared absorption layer may be configured to transmit light in a visible region and to selectively absorb at least one part of light in a near infrared region. The near infrared absorption layer includes a first near infrared absorption material including a copper phosphate ester compound and a second near infrared absorption material including at least two different organic dyes. The second near infrared absorption material has a maximum absorption wavelength (.sub.max) in a wavelength region of about 650 nm to about 1200 nm. An electronic device may include the optical filter.

A curable composition includes: a near infrared absorbing compound that includes a cation having an absorption in a near infrared range and an anion; a salt of an anion that is a component other than the near infrared absorbing compound and has a conjugate acid pKa of 8 or lower; and a curable compound.

A curable composition includes: a near infrared absorbing compound that includes a cation having an absorption in a near infrared range and an anion; a salt of an anion that is a component other than the near infrared absorbing compound and has a conjugate acid pKa of 8 or lower; and a curable compound.

The present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a blue pigment and a biosynthesis method thereof. In the present application, an indigoidine synthetase and a 4-phosphopantetheinyl transferase are expressed by a metabolically engineered strain to catalyze the biosynthesis of the blue pigment N-acetyl-indigoidine from glutamine and N-acetylglutamine, and a molecular structure of the blue pigment is inferred by mass spectrometry, nuclear magnetic resonance spectroscopy, etc. The present application achieves the catalytic synthesis of N-acetyl-indigoidine from glutamine and N-acetylglutamine in Escherichia coli (E. coli), Corynebacterium glutamicum (C. glutamicum), Saccharomyces cerevisiae (S. cerevisiae), and Streptomyces. Compared with indigoidine, N-acetyl-indigoidine has a maximum absorption wavelength of 584 nm, and a stable color having high brightness that is not easy to fade. Thus, the blue pigment shows an extensive application range and a promising industrial production prospect.

The present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a blue pigment and a biosynthesis method thereof. In the present application, an indigoidine synthetase and a 4-phosphopantetheinyl transferase are expressed by a metabolically engineered strain to catalyze the biosynthesis of the blue pigment N-acetyl-indigoidine from glutamine and N-acetylglutamine, and a molecular structure of the blue pigment is inferred by mass spectrometry, nuclear magnetic resonance spectroscopy, etc. The present application achieves the catalytic synthesis of N-acetyl-indigoidine from glutamine and N-acetylglutamine in Escherichia coli (E. coli), Corynebacterium glutamicum (C. glutamicum), Saccharomyces cerevisiae (S. cerevisiae), and Streptomyces. Compared with indigoidine, N-acetyl-indigoidine has a maximum absorption wavelength of 584 nm, and a stable color having high brightness that is not easy to fade. Thus, the blue pigment shows an extensive application range and a promising industrial production prospect.

Provided are a near infrared absorbing compound represented by General Formula (1), and a coloring agent composition containing the near infrared absorbing compound. In General Formula (1), R.sub.1 to R.sub.8 each independently represent a group selected from a phenyl group having a substituent in which a p value on Hammett's rule is 0.5 or more, an aryl group having 7 to 20 carbon atoms, which may have a substituent, or a heteroaryl group which may have a substituent, and two or more of R.sub.1 to R.sub.8 may be linked to each other to form a ring. R.sub.9 to R.sub.13 each independently represent a monovalent substituent, and five n's each independently represent an integer of 0 to 4. m is 1 or 2, and X.sup. represents a non-nucleophilic anion.

##STR00001##

Provided are a near infrared absorbing compound represented by General Formula (1), and a coloring agent composition containing the near infrared absorbing compound. In General Formula (1), R.sub.1 to R.sub.8 each independently represent a group selected from a phenyl group having a substituent in which a p value on Hammett's rule is 0.5 or more, an aryl group having 7 to 20 carbon atoms, which may have a substituent, or a heteroaryl group which may have a substituent, and two or more of R.sub.1 to R.sub.8 may be linked to each other to form a ring. R.sub.9 to R.sub.13 each independently represent a monovalent substituent, and five n's each independently represent an integer of 0 to 4. m is 1 or 2, and X.sup. represents a non-nucleophilic anion.

##STR00001##