JPS6154055B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thiopyrylium dye and a method for producing the same. More specifically, the present invention provides 2,6-di-t-butyl-4-(2,6-di-t-butyl-4-(2,6-di-t-butyl-
The present invention relates to 4H-thiopyran-4-ylidenemethyl)thiopyrylium salt and its production method. It is known that thiopyrylium and pyrylium dyes are used in a variety of applications. For example, it is used as an electron-accepting compound in direct positive photographic silver halide emulsions as disclosed in Japanese Patent Publication No. 46-40900, as well as U.S. Pat. No. 3,141,700 by Davis et al.
Spectral sensitizers for photoconductors as described in US Pat. No. 3,250,615 to Allan et al. and US Pat. No. 3,938,994 to Reynolds et al.
It is particularly useful as a spectral sensitizer for organic photoconductors. Photoconductors sensitized with thiopyrylium and pyrylium dyes are used in a variety of applications, such as those disclosed in the above-mentioned patents, but they are particularly important for xerography and electrofax electrophotography. be. However, such conventionally known thiopyrylium dyes have a drawback of having multiple absorption bands in the visible region. In particular, almost all dyes also exhibit absorption in the blue region. That is, this sensitizing dye spectrally sensitizes in multiple wavelength ranges. Therefore, when this thiopyrylium dye is used as a sensitizer for photoconductive particles to carry out color copying, for example, when obtaining color images with trichromatic mixed particles by photoelectrophoretic electrophotography, it poses a serious problem. Collide. What is photoelectrophoresis electrophotography? U.S. Patent No. 3384448
As detailed in the specification, a suspension of photoconductive photosensitive particles in an insulating liquid is placed between two electrodes, at least one of which is transparent to light;
This is an electrophotographic method based on the fact that when a differential voltage is applied to expose light through a transparent electrode, the photoconductive photosensitive particles that have been exposed to this image selectively move to one electrode, giving a visible image. When this electrophotographic method is used for color copying,
Cyan particles that are sensitive to red light, magenta particles that are sensitive to green light, and yellow particles that are sensitive to blue light are used as photosensitive particles, and a mixed suspension of these trichromatic particles is multiplied using the above-mentioned apparatus. If a color original image is imagewise exposed using white light through a color slide or by reflection printing, a subtractive image, a color positive or a color negative image is obtained on the transparent electrode in a single exposure. As disclosed in U.S. Pat. No. 3,384,448, Japanese Patent Publication No. 43-21781, Japanese Unexamined Patent Application Publication No. 143827/1983, and other publications, these particles mainly have their main absorption band corresponding to their main photosensitivity response. Cyan, magenta, and yellow pigments are used. In addition to these three-color photoconductive pigments, as described in U.S. Pat. No. 3,384,448, there is a photosensitive material in which a photoconductor contains a spectral sensitizer to make it sensitive to visible light. Sexual particles can also be used. When a color image is obtained using three-color mixed particles using such photoelectrophoretic electrophotography, when a known thiopyrylium dye is used as a spectral sensitizer for the photosensitive particles, spectral sensitization occurs in multiple wavelength ranges as described above. Therefore, only images with poor color separation could be obtained. That is, the known thiopyrylium dyes were unsuitable for color copying using photoelectrophoretic electrophotography. In order to solve the above-mentioned drawbacks, the inventor of the present invention has made repeated studies and found that it does not have the above-mentioned drawbacks and is more effective for photoconductors than conventional thiopyrylium dyes.
We have discovered a new thiopyrylium dye that provides high sensitizing ability and a method for producing the same, and have completed the present invention. An object of the present invention is to provide a thiopyrylium dye that provides high sensitizing ability to photoconductive substances and a method for producing the dye. A further object of the present invention is to provide a thiopyrylium dye for obtaining images with excellent color separation, and a method for producing the dye. The thiopyrylium dye of the present invention is 2,6-di-t-butyl-
It is 4-(2,6-di-t-butyl-4H-thiopyran-4-indenmethyl)thiopyrylium salt. The anion represented by Z includes known single atomic ions or atomic group ions consisting of a plurality of atoms having a negative charge, and is preferably a strong acid anion represented by HZ with a pKa of 5 or less, preferably a pKa of 2 or less. Specific examples of anions include monatomic ions such as halogen anions such as fluoride, chloride, bromide, iodide. The atomic group ions include organic anions such as trifluoroacetate, trichloroacetate, p-toluenesulfonate, and perchlorate, periodate, tetraloloaluminate, trichloroferrate (), tetrafluoroborate, hexafluorophosphate, Inorganic anions include sulfate, hydrogen sulfate, and nitrate. Among these, in the case of divalent anions, formally 1/2 of the anion
is interpreted to represent a monovalent anion. Among these anions, chloride, bromide, perchlorate, tetrafluoroborate, p-toluenesulfonate, and trifluoroacetate are preferred. The thiopyrylium dye of the present invention has the following chemical structural formula (2,6-di-t-butyl-4).
-Methylthiopyrylium salt [compound ()] and 2,6-di- expressed by the following chemical structural formula ()
It can be easily obtained by reacting t-butyl-4-(alkylthio)thiopyrylium salt [compound ()] in a solvent. [Manufacturing method (i)] In the formula, R has 1 to 1 carbon atoms, such as a methyl group or an ethyl group.
6 alkyl groups and substituted alkyl groups, and examples of the substituents include phenyl groups, nitro- or halogen-substituted substituted phenyl groups, alkoxy groups having 1 to 5 carbon atoms, amino groups, and sulfonic acid groups.
As R, methyl, ethyl and benzyl groups are preferred. Z represents the same anion as above. _Z1 is
The residue of the alkylating agent used when synthesizing the compound (), preferably iodine, bromine, chlorine,
Represents a halogen anion such as fluorine, an anion such as methyl sulfate, fluorosulfate or tetrafluoroborate. As the solvent, a wide range of organic solvents can be used, but a solvent that easily dissolves the reaction raw material compounds () and () is preferred. Specific examples include nitriles such as acetonitrile and propionitrile, ketones such as acetone and methyl ethyl ketone, organic carboxylic acids such as acetic acid, alcohols such as benzyl alcohol, and acid anhydrides such as acetic anhydride. The proportion of raw material compounds to be reacted is the compound ()
Compound () is used in an amount of 0.5 to 5 equivalent mol, preferably 0.8 to 1.5 equivalent mol, per 1 equivalent mol of compound (). The reaction solvent is used in an amount of 0.5 to 100 ml, preferably 1 to 50 ml, and more preferably 3 to 10 ml, per 1 g of the total amount of compounds () and (), from the viewpoint of solubility of the raw material compounds and economical efficiency. The reaction temperature is 25°C to 200°C, preferably 60°C to 140°C, which is the reflux temperature of the solvent, and the reaction time is 10 minutes to 10 hours, preferably 10 minutes to 2 hours. When acetic anhydride is used as the reaction solvent,
The highest yield was obtained when the reaction temperature was around 100°C and the reaction time was 30 minutes. A base can be added to the reaction system to promote the reaction between compounds () and (). Examples of bases that can be used include trialkylamines such as triethylamine, aromatic amines such as pyridine, and salts such as sodium acetate, sodium carbonate, and potassium carbonate. It is not necessary to add a base, but you will get better results if you do. Furthermore, a base such as pyridine can also be used as a solvent. The amount of the base is 0.01 to 20 equivalent mol, preferably 0.1 to 5 equivalent mol, per 1 equivalent mol of compound (). The thiopyrylium salt represented by the chemical structural formula (), which is the raw material compound used in the above reaction, is a new compound. Obtained by reacting with a curing agent. This new 2,6-di-tert-butyl-4H-thiopyran-4-thione was described in Reynolds et al., Journal of Heterocyclic Chemistry, No. 11.
2,6-di-t-butyl-4H-pyran-4 synthesized by the method described in Vol., p. 1075 (1974).
It was synthesized through a two-step process in which -one was reacted with phosphorus pentasulfide and the resulting product was treated with alkali hydrosulfide or alkali sulfide under an inert atmosphere. The above alkylating agents include methyl iodide,
Methylation agents such as methyl halides such as methyl bromide, methyl chloride and methyl fluoride, trimethyl oxonium tetrafluoroborate, dimethyl sulfate, and methyl fluorosulfate; halogenations such as methyl iodide, methyl bromide ethyl,
Ethylating agents such as ethyl p-toluenesulfonate, diethyl sulfate and triethyloxonium tetrafluoroborate; benzyl halides such as benzyl chloride, benzyl bromide and benzyl iodide and benzyl-p-toluenesulfonate. and commonly known alkylating agents are used. In addition, the other raw material compound used in the above reaction, thiopyrylium salt represented by the chemical structure (), is a new compound. di-t-butyl-4H-
It is obtained by treating thiopyran-4-one with a Grignard reagent or other organometallic compound, followed by treatment with an acid. As the Grignard reagent, methylmagnesium iodide, methylmagnesium bromide, and methylmagnesium chloride are preferably used, and as other organometallic compounds, methylpotassium, methylsodium, methyllithium, methylcalcium iodide, trimethylaluminum, dimethylberyllium, and trimethyl are used. Boron etc. are also used. The above acids include hydrofluoric acid, hydrobromic acid, hydroiodic acid, hydrochloric acid, perchloric acid, periodic acid, tetrafluoroboric acid,
Preferred are hexafluorophosphoric acid, sulfuric acid, nitric acid, trichloroacetic acid, trifluoroacetic acid, p-toluenesulfonic acid, and the like. The above 2,6-di-t-butyl-4H-thiopyran-4-one is a 2,6-di-t-butyl-4-(alkylthio or arylthio)thiopyrylium salt represented by the chemical structural formula (). Obtained by hydrolysis. An oxygen-free atmosphere is preferably a state in which the air in the reaction system is replaced with a rare gas or an inert gas. The synthesis method of these raw material compounds is disclosed in Japanese Patent Application No. 1983-37249 filed on March 28, 1972 and June 29, 1972.
Japanese Patent Application No. 54-81523, No. 54-81524 and
No. 54-81525. The target compound thus obtained can be purified by filtering the crystals and recrystallizing them from a solvent such as ethyl acetate according to a conventional method. As another method for synthesizing the compound of the present invention, 5 to 50%
It is produced by reacting this with 2,6-di-t-butyl-4H-thiopyran-4-one in 50 ml of acetic anhydride at reflux temperature for 10 minutes to 5 hours (preferably 10 minutes to 2 hours). Method [Production method (ii)], this 2,6-di-t-butyl-4-methylthiopyrylium salt and an ortho-nitroaryl compound such as 1-fluoro-2,4-dinitrobenzene [Production method]
(iii)] or 2,6-di-t-butylthiopyrylium salt [Production method (iv)], respectively, in a solvent, or this 2,6-di-t-butylthiopyrylium salt A method obtained by reacting a malonic acid salt with malonic acid in the presence or absence of a base such as sodium acetate [Production method (v)], and 2,6-di-t-butyl-4-methoxythiopyrylium salt and malonic acid in the presence of a trialkylamine or the like [Production method (vi)]. Among these production methods, method (i) is the most preferred because compound (), which is one of the raw materials, can be obtained early in the synthesis stage and the yield is higher than the others. . As a conventional method for producing a thiopyrylium dye, in the above-mentioned US Pat. No. 3,938,994, a thiopyrylium dye is obtained by a method of reacting a pyranomethylene pyrylium salt with sodium sulfide. When applied to the synthesis of dyes, only one pyran ring of the pyranomethylenepyryllium salt is converted to a thiopyran ring, but two oxygen atoms are not converted to sulfur atoms at the same time, so the synthesis of the thiopyrylium dye of the present invention could not be applied. The thiopyrylium dyes associated with the present invention are effective in conventional electrophotography and photoelectrophoretic electrophotography methods such as xerography and electrofaxing. It is particularly useful in color electrophotography using photoconductive particles. However, it goes without saying that this description does not limit the usage. FIG. 1 shows the spectral sensitivity spectrum when the novel thiopyrylium dye according to the present invention is used as a spectral sensitizer for poly-N-vinylcarbazole.
FIG. 2 shows a spectral sensitivity spectrum when a conventional thiopyrylium dye is used. As is clear from a comparison of Figures 1 and 2, the new thiopyrylium dye has 2 and 6 thiopyran rings.
Because it has a t-butyl group at the position, there is no sub-absorption in the vicinity of 400 nm, unlike conventional aryl group-containing dyes, and photoconductor compositions using this new thiopyrylium dye as a spectral sensitizer can be used in the visible range. It is not sensitive to light in the blue region, especially in the 400-450 nm range. Therefore, color photoelectrophoretic electrophotographic photosensitive particles containing this new thiopyrylium dye as a sensitizer have improved color separation from blue-sensitive yellow particles, unlike those made using known thiopyrylium dyes. be able to. For example, magenta particles containing the compound () as a sensitizing dye in the green region also provide images with good color separation that do not mix with yellow particles. In addition, the novel thiopyrylium dye () of the present invention
When used as a sensitizer for photoconductors, especially organic photoconductors such as poly-N-vinylcarbazole, triarylamine, triarylmethane ()
was found to give a more sensitive photoconductor than traditional thiopyrylium dyes (2009). The reason for this is not yet clear, but one of the reasons seems to be that the t-butyl substituent of compound () increases its compatibility with the organic photoconductor. Next, an example for producing a thiopyrylium salt of the present invention and a comparative example with a conventional thiopyrylium salt will be shown. Example 1 2,6-di-t-butyl-4-(2,6-di-
Process for producing t-butyl-4H-thiopyran-4-ylidenemethyl)thiopyrylium perchlorate [compound ()] (i) 34.6 g of 2,6-di-t-butyl-4H-pyran-4-one is anhydrous Dissolve 73g of phosphorus pentasulfide in 240ml of benzene and stir for 2 hours.
The mixture was heated under reflux for 30 minutes. After the reaction was completed, the benzene solution was removed by decanting and aqueous ammonia was added to the residue to decompose phosphorus pentasulfide, followed by extraction with ether and drying using anhydrous sodium sulfate. The solvent of the benzene solution was distilled off under reduced pressure, and the residue was extracted with hexane and concentrated to obtain 16.0 g of reddish crystals. The ether extract and the oil that was not extracted with hexane were combined and purified through a silica gel column using benzene to obtain an additional 6.8 g of crystals. Total yield 22.8g, yield 61%, melting point 108-108.5℃
2,6-di-t in flesh-colored crystals (hexane recrystallization)
-Butyl-4H-pyran-4-thione was obtained.
6.64 g of this compound was dissolved in 330 ml of hexamethylene phosphoric triamide and purged with argon gas for 20 minutes. Heat and stir on an oil bath at 85-90°C, and add 19.8 g of sodium bisulfide (Wako Pure Chemical's NaSH/XH ₂ O approximately 70% to 70-80% of phosphorus pentoxide under an argon atmosphere).
) was added once for 30 minutes. After stirring at the same temperature for 1 hour and 30 minutes, the reaction solution was poured into water to complete the reaction. The resulting crystals were filtered and dried. Recrystallized from hexane. Red crystals of 2,6-di-t-butyl-4H-thiopyran-4-thione with a melting point of 162° C. were obtained in an amount of 1.78 g and a yield of 25%. Then this compound 1.55
was heated under reflux for 1 hour with 20 ml of acetone and 5 ml of methyl iodide. After distilling off the solvent under reduced pressure, the residue was recrystallized from acetone to obtain 1.55 g of prismatic red crystals. 2,6-di-t- with a yield of 63% and a melting point of 150°C to 155°C (decomposition).
It was butyl-4-(methylthio)thiopyrylium iodide [compound (2)]. Elemental analysis value Calculated value as C ₁₄ H ₂₃ S ₂ I C = 43.98% H = 6.06℃, S = 16.77% Measured value C = 43.87%, H = 6.14%, S = 16.53% Infrared absorption spectrum (wave number cm ^-1 ) 1567,
1475, 1118 Nuclear magnetic resonance spectrum (chemical shift, unit ppm, trimethylsilane standard) (Proton) 99.6MHz in deuterated dimethyl sulfoxide 1.59, 3.06, 8.44 each singlet, area ratio 18:
3:2 (carbon-13) 25.5MHz in deuterium dimethyl sulfoxide 177.13, 172.29, 126.89, 41.01, 30.19,
15.50 Ultraviolet/visible absorption spectrum (wavelength nm, logε in Katsuko, in chloroform) 271 (3.95), 303 (3.68), 365 (4.35), 482
(2.95) (ii) 1.30 g of 2,6-di-t-butyl-4-(methylthio)thiopyrylium iodide produced in the above process and 10 ml of dimethyl sulfoxide and 1 ml of water.
ml and heated and stirred on an oil bath at 85 to 90°C for 3 hours. The reaction solution was poured into water and extracted with diethyl ether. After drying the diethyl ether solution over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the residue was passed through an alumina column using a 1:1 mixed solvent of benzene diethyl ether to obtain 740 mg of crystals. Recrystallize from cyclohexane with a yield of 97%. 2,6-di-colorless crystals with a melting point of 97-98℃
t-Butyl-4H-thiopyran-4-one was obtained. 550 mg of this compound was dissolved in 20 ml of diethyl ether, and while cooling to about -10°C, 8.6
ml of methylmagnesium iodide in diethyl ether (2.7 mmol) was added dropwise. After the dropwise addition was completed, stirring was continued for 45 minutes at room temperature (approximately 23°C).
Saturated aqueous ammonium chloride solution was added. After decanting the ether solution, the ether was distilled off under reduced pressure, and 20 ml of 35% perchloric acid was added to the residue, which was heated on a hot water bath to precipitate crystals. The crystals were filtered, washed with cold water, further washed with diethyl ether, and dried. The yield was 470 mg. Recrystallization from ethanol gave colorless crystals of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate [compound (2)] with a melting point of 192-193°C. Elemental analysis Calculated values as C ₁₄ H ₂₃ ClO ₄ S C = 52.08%, H = 7.18%, S = 9.93% Actual values C = 52.00%, H = 7.28%, S = 9.75% Infrared absorption spectrum (wave number cm ^-1 ) 1590,
1375, 1085 Nuclear magnetic resonance spectrum (chemical shift, unit ppm, trimethylsilane standard) (Proton) in heavy acetone at 99.6MHz 1.67, 2.96, 8.81 each singlet, area ratio 18:
3:2 (Carbon-13) 25.5MHz in heavy acetone 184.87, 167.08, 134.67, 42.53, 31.18,
28.75 Ultraviolet/visible absorption spectrum (wavelength nm, logε in Katsuko, in acetonitrile) 302 (3.97), 262 (3.88), 213 (4.47) (iii) The above 2,6-di-t-butyl-4-methylthiopyryl Rium perchlorate 200mg and 2.6
-230 mg of di-t-butyl-4(methylthio)thiopyrium iodide in 1 ml of acetic anhydride at 100%
The mixture was heated and stirred at ℃ for 30 minutes. After cooling, the crystals were filtered and recrystallized from ethyl acetate to obtain compound ().
I got it. Yield 135 mg Melting point 195-198℃ Elemental analysis value Calculated value as C ₂₇ H ₄₁ S ₂ ClO ₄ C = 61.28%, H = 7.81%, S = 12.11% Measured value C = 60.99%, H 7.85%, S = 12.40 % Infrared absorption spectrum (wave number cm ^-1 ) 1567,
1480, 1090 nuclear magnetic resonance spectra (chemical shift, ppm, trimethylsilane standard in deuterated acetone at 24°C) 1.53, 7.81, 8.49, each singlet, area ratio is
The ratio was 36:4:1. Ultraviolet/visible absorption spectrum (wavelength nm, ε in Katsuko, in acetonitrile 573 (72000), 536 (23700), 360 (6400) 295
(17700), 249 (15600) Example 2 1 g of poly-N-vinylcarbazole and Example 1
3 mg of the compound () obtained above was dissolved in 10 g of 1,2-dichloroethane and coated on a polyester film coated with aluminum using a No. 16 rod bar.
A photoreceptor was prepared by drying at 55°C for one day. This photoreceptor was charged to +450V by corona discharge of +6kV using a commercially available device, and then the surface was irradiated with light using a tungsten lamp at an illuminance of 4.5 lux to increase its surface potential.
The exposure amount was obtained by determining the time (seconds) it took for the voltage to reach 225V. The result was E1/2 = 67 lux seconds. Comparative Example 1 Photoreceptors were prepared according to the same photoreceptor manufacturing method as in Example 2, except that the compound () shown in FIG. Perform the same measurements as in the example and see Table (1)
The results were obtained. Known thiopyrylium dyes ()
Comparative Example 1 using Example 2 is a control for comparison with Example 2.

[Table] The embodiments are shown below. (1) 2.6 represented by the chemical structural formula () below
-di-t-butyl-4-(2,6-di-t-butyl-4H-thiopyran-4-ylidenemethyl)thiopyrylium salt. (2) 2.6 represented by the chemical structural formula () below
-di-t-butyl-4-methylthiopyrylium salt and 2.
6-di-t-butyl-4-(alkylthio)thiopyrylium salt, 2,6-di-t-butyl- represented by the following chemical structural formula (), which is characterized in that it is reacted with
A method for producing 4-(2,6-di-t-butyl-4H-thiopyran-4-ylidenemethyl)thiopyrylium salt. (In the above formula, R represents an alkyl group or a substituted alkyl group, Z represents an anion of a strong acid, and Z ₁ represents a leaving group of an alkylating agent.) (3) Z is an anion of a strong acid with a pKa of 5 or less. The thiopyrylium salt of embodiment (1). (4) The production method according to embodiment (2), in which the reaction is carried out in a solvent. (5) The production method according to embodiment (2), wherein Z is an anion of a strong acid with a pKa of 5 or less. (6) The method of embodiment (2), wherein Z ₁ is at least one anion selected from halogen, methylsulfate, fluorosulfate, and tetrafluoroborate. (7) Embodiment (2) in which the reaction is carried out at the reflux temperature of the solvent
manufacturing method. (8) R is an unsubstituted alkyl group having 1 to 6 carbon atoms; and an alkyl group substituted with a phenyl group, a nitro or halogenated phenyl group, an alkoxy group having 1 to 5 carbon atoms, an amino group, and a sulfonic acid group The method of embodiment (2), wherein the group is selected from (9) 2,6-di-t-butyl-4-(alkylthio)thiopyrylium salt [for 1 equivalent mole of 2,6-di-t-butyl-4-methyl-thiopyrillium salt [compound ()]] Compound()〕
Embodiment (2) in which 0.5 to 5 equivalent moles of
manufacturing method.

[Brief explanation of the drawing]

Figure 1 shows the spectral sensitivity spectrum when the novel thiopyrylium dye of the present invention is used as a spectral sensitizer for poly-N-vinylcarbazole.
The figure shows a spectral sensitivity spectrum when a conventional thiopyrylium dye is used as a spectral sensitizer for poly-N-vinylcarbazole.

Claims (1)

[Scope of Claims] 1 2,6-di-t-butyl-4-(2,6-di-t-butyl-4-(2,6-di-t) represented by the following chemical structural formula ()
-Butyl-4H-thiopyran-4-ylidenemethyl)thiopyrylium salt. 2 2.6 represented by the following chemical structural formula ()
-di-t-butyl-4-methylthiopyrylium salt and 2.6 represented by the following chemical structural formula ()
-di-t-butyl-4-(alkylthio)thiopyrylium salt, 2,6-di-t-butyl-4 represented by the following structural formula (), which is characterized by being reacted with
-(2,6-di-t-butyl-4H-thiopyran-
Method for producing 4-ylidenemethyl)thiopyrylium salt. (In the above formula, R represents an alkyl group or a substituted alkyl group, Z represents an anion of a strong acid,
Z ₁ represents a leaving group of the alkylating agent. )