Yamamoto Chemicals, Inc.

Yamamoto Kagaku Gosei Co., Ltd.

Yasuhisa Iwasaki

Shigeo Fujita

Nobuaki Sasaki

Keiki Chichiishi

Yojiro Kumagae

Hiroaki Harada

Fumitoshi Emori

Takao Yoshimura

The invention provides near infrared absorbing materials showing high light-to-heat conversion efficiency and high sensitivity to lasers whose emission bands are within the range of 750 nm to 900 nm, original plates for direct printing plate making, and novel compounds which can be applied to such absorbing materials and plates. The compounds are polymethine compounds of the general formula (I) A detailed description of general formula (I) may be found in the specification.wherein Rrepresents an alkoxy group which may be substituted; Rrepresents an alkyl group which may be substituted; Rand Reach represents a lower alkyl group or Rand Rtaken together represent a ring; X represents a hydrogen atom, a halogen atom or a substituted amino group; Y represents an alkoxy group which may be substituted or an alkyl group which may be substituted; Z represents a charge neutralizing ion.

Polymethine compounds, method of producing same, and use thereof

Polymethine compound and near-infrared absorbing material comprising same

The invention provides near infrared absorbers showing high light-to-heat conversion efficiency and high sensitivity to laser beams whose emission region is within the range of 750 nm to 900 nm, plates for direct printing plate making, and novel compounds which can be used in such absorbers or plates. The compounds are polymethine compounds of the general formula (I) shown below and the near infrared absorbers comprise the polymethine compounds.

A method of producing a high melting point 3-dibutyl amino-6-methyl-7-anilinofluoran characterized by peaks at diffraction angle (2 .theta.) of 6.9.degree., 11.0.degree., 18.5.degree. and 18.9.degree. in X-ray diffractiometry using Cu-K .alpha. ray and having a melting point in the range of 179.degree.-186.degree. C., which comprises: condensing 2-(4-dibutylamino-2-hydroxy-benzoyl) benzoic acid with 4-methoxy-2-methyldiphenylamine in the presence of concentrated sulfuric acid to provide a phthalide at a temperature in the range of 0.degree.-50.degree. C., neutralizing the phthalide, and then subjecting the phthalide to ring closure reaction using an alkali in an amount of 0.5-15 mols per mol of the compound used in smaller amounts of 2-(4-dibutylamino-2-hydroxy-benzoyl) benzoic acid and 4-methoxy-2-methyldiphenylamine at a temperature of not less than 50.degree. C. in the presence or absence of an organic solvent.

Method of producing 3-dibutylamino 6-methyl-7-anilinofluoran

Chromogenic compounds of colorless or lightly colored form are disclosed having the following structural formula: ##STR1## wherein X represents an optionally substituted aminophenyl, indolyl, julolidinyl, kairolyl, piperidinophenyl, pyrrolidinophenyl, morpholinyl, carbazolyl or indolizinyl radical. The compounds of this invention are eligible for use in pressure-sensitive and heat-sensitive record materials and manifold marking systems.

Certain bis(benzoyl)pyridine compounds

This invention relates to an improvement in the process for preparation of 2-(amylbenzoyl)benzoic acid containing a high percentage of 2-(t-amylbenzoyl)benzoic acid. More particularly it relates to a process for preparation of 2-(amylbenozyl)benzoic acid wherein said 2-(amylbenzoyl)benzoic acid is prepared by reacting t-amylbenzene with phthalic anhydride in the presence of Lewis acid, characterized by that 2-(amylbenzoyl)benzoic acid containing a high percentage of 2-(t-amylbenzoyl)benzoic acid is produced by suppressing the undesirable isomerization reaction of the amyl radical by applying one of the means selected from the group consisting of the means of introducing an inert gas into the reaction system and the means of reducing the pressure of the reaction system. 2-(Amylbenzoyl)benzoic acid is a compound useful as the starting material of preparation of 2-amylanthraquinone which is an effective organic catalyst in the manufacture of hydrogen peroxide.

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Nara, Japan

Yasuhisa Iwasaki