Organic compounds -- part of the class 532-570 series – Organic compounds – Azo
Reexamination Certificate
2000-07-06
2001-09-04
Powers, Fiona T. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Azo
C534S710000
Reexamination Certificate
active
06284877
ABSTRACT:
The present invention relates to a novel sulfonamide compound and a method for its production, a metal chelate compound employing the sulfonamide compound, and an optical recording medium employing the metal chelate compound. The sulfonamide compound of the present invention is useful in the field of colorants, e.g. as a colorant for plastics, a dye for fibers, a dye for optical filters, a dye for printing inks or a dye for heat transfer printing, and it is further useful as a metal ion indicator.
Various type of optical discs have been proposed. Among them, there is one containing an organic dye in the recording layer. As the inorganic dye, various types have been studied, but none of them has been fully satisfactory.
It is an object of the present invention to provide an intermediate useful for the synthesis of an azo dye suitable for an optical disc, particularly an optical disc having a metal reflective layer and designed to use a semiconductor laser of a short wavelength.
In recent years, development of semiconductor lasers having short wavelengths has been progressed, and an optical recording medium capable of recording and retrieving information in a high density by means of a laser beam having a shorter wavelength than conventional 780 nm or 830 nm, has been desired. Optical recording media heretofore proposed include a magneto-optical recording medium, a phase-change recording medium, a chalcogen oxide optical recording medium, and an organic dye type optical recording medium Among them, the organic dye type optical recording medium is considered to have a significance in that it is inexpensive and can be readily prepared. Further, the organic dye type optical recording medium includes a recordable compact disc (CD-R) which is widely known as a type wherein a metal layer having high reflectance is laminated on an organic dye layer.
With an organic dye type optical recording medium for recording by means of a semiconductor laser having a short wavelength, high density recording can be carried out by reducing the diameter of the laser beam by employing a laser having a wavelength shorter than the wavelength of the laser for CD-R. However, discs currently used for CD-R have a problem that when a laser having a wavelength of e.g. 680 nm, 650 nm or 635 nm, is used, the reflectance tends to be so low that record retrieving can hardly be carried out. The recording media currently proposed have problems such that deformation of the recording layer due to decomposition of the dye during recording, is substantial, no adequate degree of modulation can be obtained, and the light resistance or durability is inadequate.
The present inventors have previously proposed in JP-A-3-268994 an optical recording medium employing a metal chelate compound comprising a novel azo compound and a metal, which is excellent in light resistance and durability. However, as an optical recording medium having a metal reflective layer, the recording and retrieving properties by means of a semiconductor laser having a short wavelength, have been inadequate.
Further, in Japanese Patent Application No. 8-187794, the present inventors have proposed an optical recording medium employing a metal chelate compound comprising an azo type compound and a metal, which is capable of recording and retrieving information by means of a semiconductor laser having a short wavelength. However, the recording medium employing a metal chelate compound of the present invention, is one whereby the record and retrieving characteristics and the light resistance and durability have been further improved.
It is an object of the present invention to provide a metal chelate compound made of an azo compound and a metal, which is useful for an optical recording medium which solves the above problems, and an optical recording medium prepared by employing such a metal chelate compound, which is excellent in information recording and retrieving characteristics by means of a semiconductor laser having a short wavelength and which has good light resistance and durability.
The intermediate of the present invention is a sulfonamide compound of the formula (1):
wherein X is a hydrogen atom, an alkyl or alkoxy group which may be substituted, or a halogen atom, Y is an alkyl group having at least two fluorine atoms, and each of R
1
and R
2
which are independent of each other, is an alkyl group which may be substituted, or R
1
may be bonded to X or R
2
to form a ring.
Preferably, X is a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group or a methoxyethoxy group, Y is a C
1-3
alkyl group having at least two fluorine atoms, particularly a trifluoromethyl group or a 2,2,2-trifluoroethyl group, each or R
1
and R
2
which are independent or each other, is a C
1-6
alkyl group which may have a substituent. The substituent may, for example, be a C
1-6
alkoxy group, a phenyl group, a cyclohexyl group or a vinyl group. Further, when R
1
is bonded to X or R
2
to form a ring, the ring is preferably a six-membered ring which may contain an oxygen atom or the like, and a C
1-4
alkyl group such as a methyl group or an ethyl group, may be substituted on the ring.
Typical examples of the sulfonamide compound of the present invention will be given in the following Table 1.
TABLE 1
No. 1
No. 2
No. 3
No. 4
No. 5
No. 6
No. 7
No. 8
No. 9
No. 10
No. 11
No. 12
No. 13
No. 14
No. 15
No. 16
The sulfonamide compound of the present invention can be produced by reacting an aniline of the following formula (2) with an alkyl sulfonyl halide or an alkyl sulfonic anhydride, which has at least two fluorine atoms in the alkyl group:
wherein X, R
1
and R
2
are as defined in the formula (1).
This reaction is carried out usually at a temperature of from −20 to +80° C. Preferably, the reaction is initiated at a temperature of at most 20° C., more preferably at most 0° C., and the reaction is terminated at a temperature of from 20 to 30° C. This reaction is preferably conducted in a solvent. As the solvent, various types may be employed, such as benzene, toluene, xylene, n-hexane or methylene chloride. Preferred is methylene chloride or toluene.
When trifluoromethane sulfonic anhydride is used as the alkyl sulfonic anhydride, a trifluoromethane sulfonate of the sulfonamide compound can be obtained. The trifluoromethane sulfonate may be reacted with an alkali such as sodium acetate or sodium hydrogen carbonate in a suitable solvent such as methanol, ethanol or N,N-dimethylformamide, to obtain the desired free sulfonamide compound.
In the following step of diazotization coupling, the trifluoromethane sulfonate may be used as it is.
The compound of the formula (2) can be produced by various known methods. For example, a compound of the formula (2) wherein X is a hydrogen atom, and each of R
1
and R
2
is an alkyl group which may be substituted, can be readily produced by alkylating 3-aminoacetanilide which is commercially readily available, followed by hydrolysis. Further, a compound wherein X and R
1
together form a ring, such as a compound corresponding to No. 9 in Table 1, can be produced by alkylating tetrahydroquinoline by means of an alkylating agent such as n-butyl bromide, followed by nitration and reduction. A compound wherein R
1
and R
2
are bonded to form a ring, such as a compound corresponding to No. 7 in Table 1, can be produced by nitrating N-phenylmorpholine, followed by reduction.
The sulfonamide compound of the present invention can be used as the coupling component in preparation of an azo dye. The azo dye thereby obtainable, can be used for various applications such as for optical recording media, for liquid crystals, for heat transfer printing, for fibers or for coloring plastics. For example, a nickel-containing azo dye obtainable by the following reaction, is useful as a dye for absorbing a laser beam for an optical recording medium. In the formulae, D is a C
1-3
alkyl group.
The present invention provides a metal chelate compound obtained from an azo compound of the followi
Kurose Yutaka
Maeda Shuichi
Okamoto Yuko
Suzuki Yuki
Mitsubishi Chemical Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Powers Fiona T.
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