JPS64395B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides novel thiopyrylium salts, namely:
2,6-di-t-butyl-4-[5-(2,6-
This invention relates to di-t-butyl-4H-thiopyran-4-ylidene)pent-1,3-dienylthiopyrylium salt and its production method.

It has been known that thiopyrylium and pyrylium dyes are used for various purposes. 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. Patent No. 3141700 by Davis et al. No. 3,250,615, U.S. Pat. No. 3,938,994 to Reynolds et al., and also Research Disclosure No. 16321, November 1977, No. 5.
It is useful as a spectral sensitizer for photoconductors, particularly for organic photoconductors, as described on page 1.

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.

However, since such conventionally known thiopyrylium dyes have an absorption band in the visible range, when these thiopyrylium dyes are used as a sensitizer for a photoconductor, a colorless and transparent photoconductive composition that exhibits absorption in the visible range can be obtained. I couldn't do anything.

Therefore, an object of the present invention is to provide a novel thiopyrylium compound that is colorless and transparent, has absorption in the far-infrared to near-infrared range, and has high sensitizing ability, and a method for producing the same.

The thiopyrylium salt of the present invention is 2,6-di-t-butyl-
It is 4-[5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]thiopyrylium salt.

In the formula, Z represents an anion.

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 preferably from the viewpoint of synthesis.
An anion which is an acid represented by HZ and is a strong acid with a pKa of 5 or less, more preferably a pKa of 2 or less. Specific examples of anions include monatomic ions such as halogen anions, such as fluoride ions, chloride ions, bromide ions, and iodide ions. The atomic group ions include organic anions such as trifluoroacetate ion, trichloroacetate ion, p-toluenesulfonate ion, and perchlorate ion, periodate ion, tetrachloroaluminate ion, and trichloroferate ion (). , tetrafluoroborate ion, hexafluorophosphate ion, sulfate ion, hydrogen sulfate ion, nitrate ion, and other inorganic anions. Among these, in the case of divalent anions, formally 1/2 of the anion is 1
It is interpreted as representing a valent anion. Among these anions, chloride ion, bromide ion,
Perchlorate ion, tetrafluoroborate ion, p-toluenesulfonate ion, and trifluoroacetate ion are preferred.

As shown in Figure 1, the thiopyrylium salt of the present invention has its main absorption in the far-infrared to near-infrared region (650 to
900nm) and does not substantially absorb visible light. When this salt is used as a sensitizing dye for an organic photoconductor that does not absorb visible light, such as poly-N-vinylcarbazole, a photoconductive layer having an optical density for visible light of about 0.05 or less can be formed. Therefore, by providing this photoconductive layer on a support, a colorless and transparent photoreceptor can be produced. The maximum absorption wavelength in poly-N-vinylcarbazole is 828 nm.
This photoreceptor is used for ordinary electrophotography using tungsten light as a light source, and as it is sensitive to far-infrared to near-infrared as shown in Figure 2, light sources in this region (e.g. semiconductor lasers) are used. It is particularly effective in electrophotography, and photoreceptors using the compounds of the present invention have high sensitivity.

The thiopyrylium salt of the present invention can be produced by the following method.

[Production method 1] From 2,6-di-t-butyl-4-methylthiopyrylium salt [compound ()] to 1-phenylamino-3-phenylimido-1-propene [compound ()], or from compound () and acid A method of producing salts by reacting them.

Here, Z represents an anion.

Acids that form salts with compounds () are generally
Acids with a PKa of ₄ or less, preferably 1 or less, such as hydrochloric acid, hydrobromic acid, sulfuric acid, and the like.

The above reaction is carried out in carboxylic anhydride,
There are two ways to do it in an amine.

In a method in which the reaction is carried out in a carboxylic anhydride, the carboxylic anhydride contributes to the reaction system as a deanilation agent.

For example, acetic anhydride is used as the carboxylic anhydride. In order to dissolve the reaction raw materials in the carboxylic anhydride, an auxiliary solvent that does not react with the raw materials, catalyst, and products of the reaction system, such as acetic acid, nitrobenzene, etc., may be added. This reaction requires the presence of a base, and the base is generally an organic base such as an alkali metal salt of acetate such as sodium acetate or potassium acetate, or an alkyl amine, preferably a primary amine having 1 to 10 carbon atoms, with a total number of carbon atoms Secondary amines having 2 to 20 carbon atoms, tertiary amines having a total carbon number of 3 to 30, aromatic amines, and nitrogen-containing aromatic amines are used. Examples of these amines include triethylamine, piperidine, aniline, dimethylaniline, pyridine, and quinoline.

The amount of the base is 0.2 to 100 mol, preferably 0.5 to 20 mol, per mol of 2,6-di-t-butyl-4-methyl-thiopyrylium salt.

The amount of carboxylic anhydride is 2,6-di-t in weight ratio
-Butyl-4-methylthiopyrylium salt per 1
It is 0.1-100, preferably 1-50.

When carrying out in an amine, a co-solvent such as ethanol, acetic acid or nitrobenzene may be added in the same manner as above.

As the amine, the same ones as mentioned above are used. The amount of amine is 2,6-di-t-butyl-
Generally per mole of 4-methylthiopyrylium salt
The amount used is 0.5 to 200 mol, preferably 1 mol to 100 mol.

The above reaction is generally carried out at 50-200°C, preferably 80-200°C.
It is carried out at 140℃. The amounts of compounds () and () may be chemical equivalents, but generally 1-phenylamino-3-phenylimide-1- per mole of 2,6-di-t-butyl-4-methylthiopyrylium salt.
0.3 to 1 mol of propene is used. The reaction time is generally 1 minute to 1 hour, although it depends on the temperature, type of solvent, etc.

The yield of compound () is approximately 60% based on 2,6-di-t-butyl-4-methylthiopyrylium salt.
It is.

[Production method 2] 2,6-di-t-butyl-4-methylthiopyrylium salt and 1, represented by the chemical structural formula ()
A method of producing by reacting with 1,3,3-tetraalkoxypropane.

Here, R is a C ₁ to C ₄ alkyl group. Examples of commonly used compounds () include 1,1,3,3-tetramethoxypropane,
Examples include 1,1,3,3-tetraethoxypropane.

The reaction is carried out in the presence of an amine in a carboxylic acid such as acetic acid or a carboxylic anhydride such as acetic anhydride. The amount of carboxylic acid or carboxylic acid anhydride is 0.1 to 100, preferably 1 to 50, per 1 of 2,6-di-t-butyl-4-methylthiopyrylium salt by weight.

As the amine, the same one used in Production Method 1 can be used. The amount of amine is 2,6-di-t
It is generally used in an amount of 0.5 to 200 mol, preferably 1 mol to 100 mol, per mol of -butyl-4-methylthiopyrylium salt. Reaction temperature is generally 50-200℃
It is preferably carried out at a temperature of 80 to 140°C.

The amounts of thiopyrylium salt and tetraalkoxypropane may be chemically equivalent, but generally 0.5 to 10 moles of the latter are used per 1 mole of the former. The reaction time is generally 1 minute to 1 hour, although it depends on reaction conditions such as reaction temperature.

The compound () used in Production Methods 1 and 2 is, for example, 2,6-di-t-butyl-4H-pyran-4-
It can be synthesized from ion (compound (i)) through the following steps.

That is, compound (i) is heated in the presence of phosphorus pentasulfide to obtain compound (ii) [step (1)], which is then heated under an inert gas stream.
Compound (iii) is obtained by reacting with an alkali sulfide such as sodium sulfide or an alkali hydrosulfide such as potassium hydrosulfide [step (2)]. Next, compound (iii) is hydrolyzed to directly obtain compound (v) [step (3)], or compound (iii) is reacted with a methylating agent to obtain compound (iv) [step (3)]. 3)′] Hydrolyze this to obtain compound (v) [Step (4)]. Compounds obtained in this way
Compound () is obtained by treating (v) with a Grignard reagent and then with an acid [Step (5)].

Compound (i) was prepared in the Journal of Heterocyclic Chemistry by Reynolds et al.
(Journal of Heterocyclic, Chemistry)” No. 11
It can be synthesized by the method described in Vol., p. 1075 (1974).

(Details about each of the above steps are described in the following applications by the present inventors. Steps (1) and (2): Patent Application No. 81523, filed in 1978; Step (3): Patent Application No. 81525, filed in 1978. No., Process (3)': 1978 Patent Application No. 81524
No., Process (4): 1978 Patent Application No. 81525, Process
(5): Specifications of Patent Application No. 37249 of 1972) Production example of compound () according to the above steps (1) 2,6-di-t-butyl-4H-pyran-4
-Production of thione [compound (ii)].

34.6 g of 2,6-di-t-butyl-4H-pyran-4-one was dissolved in 240 ml of anhydrous benzene, 73 g of phosphorus pentasulfide was added, and the mixture was heated under reflux for 2 hours and 30 minutes with stirring.

After the reaction was completed, the benzene solution was removed by decanting, aqueous ammonia was added to the residue to decompose phosphorus pentasulfide, and the mixture was extracted with ether and dried 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 crystal compound (ii). 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.

(2) Production of 2,6-di-t-butyl-4H-thiopyran-4-thione [compound (iii)].

6.64 g of compound (ii) was dissolved in 330 ml of HMPA (hexamethylphosphoric triamide) and argon gas was passed through the solution for 20 minutes.

Heat and stir on an oil bath at 85 to 90°C, and add 19.8 g of sodium bisulfide (Wako Pure Chemical Industries, Ltd.) under an argon atmosphere.
About 70% NaSH.×H ₂ O (vacuum dried over phosphorus pentoxide at 70-80° C. for 1 day) 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. Filter the formed crystals,
Dry. Recrystallization from hexane gave compound (iii).

Yield: 1.78g Yield: 25% (3) Method for producing 2,6-di-t-butyl-4-(methylthio)thiopyrylium iodide [compound (iv)].

1.55 g of compound (iii) 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 of compound (iv). Yield 63% (4) Method for producing 2,6-di-t-butyl-4H-thiopyran-4-one [compound (v)].

1.30 g of 2,6-di-t-butyl-4-methylthio-thiopyrylium iodide was heated and stirred with 10 ml of dimethyl sulfoxide and 1 ml of water on an oil bath at 85-90° 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 (volume ratio) mixed solvent of benzene and diethyl ether, yielding 740 mg of the compound (v ) crystals were obtained.

Yield 97%. Recrystallize from cyclohexane.

(5) A method for producing 2,6-di-t-butyl-4-methylthiopyrylium perchlorate [compound ()].

The obtained 2,6-G-t- under an argon atmosphere
Butyl-4H-thiopyran-4-one 550mg 20
ml of diethyl ether, and while cooling to about -10°C, 8.6 ml of a diethyl ether solution (2.7 mmole) of methylmagnesium iodide was added dropwise.

After the dropwise addition, stirring was continued for 45 minutes at room temperature (approximately 23°C), and then a saturated aqueous ammonium chloride solution was added. After the ether solution was decanted, the ether was distilled off under reduced pressure, and 20 ml of 35% perchloric acid was added to the residue and heated on a hot water bath to precipitate crystals. The crystals were filtered, washed with cold water, further washed with diethyl ether and dried. Yield is 470
mg (yield 63%). Next, recrystallization from ethanol produces colorless crystals of 2,6-
Di-t-butyl-4-methylthiopyrylium perchlorate (compound) was obtained.

Example 1 2,6-di-t-butyl-4-[5-(2,6
-Di-t-butyl-4H-thiopyran-4-ylidene)-penta-1,3-dienyl]-thiopyrylium perchlorate [compound ()] synthesis method by [Production method 1] 2,6-di-t -Butyl-4-methylthiopyrylium perchlorate (compound) 0.193g and 1
-Phenylamino-3-phenylimide-1-propene (0.160 g) was heated at 100°C for 3 minutes in a test tube, and to this was added 0.193 g of compound () and sodium acetate.
0.24 g and 1 ml of acetic anhydride were added and heated at 100°C for 30 minutes. After cooling, 50 ml of diethyl ether was added to precipitate crystals.

The crystals were filtered and dried.

Next, it was recrystallized from ethanol to obtain 0.22 g of needle-shaped crystals.

The melting point was 232°C.

It was confirmed to be compound () from elemental analysis values and spectrum data.

Elemental analysis Calculated value as C ₃₁ H ₄₅ S ₂ ClO ₄ C = 64.06% H = 7.80%, S = 11.03% Actual value C = 63.95%, H = 7.85% S = 10.93% Infrared absorption spectrum (wave number cm ^-1 ) 1480, 1460,
1130,730 Nuclear magnetic (proton) resonance spectrum (chemical shift, unit ppm, trimethylsilane standard, deuterium chloroform, +24°C) 1.44 (S, 36H), 7.48 (S, 4H), 8.35 (d,
d, 2H, J=12.5, J=13.7) 6.51(t,
1H, J = 12.5) 6.28 (d, 2H, J = 13.7) S, d, t represent a singlet, doublet, triplet, respectively; d, d represent two sets of doublets; The numbers represent the area ratio and J represents the coupling constant (unit: Hertz).

Electron spectrum wavelength (nm), in cutlet: extinction coefficient, (in acetonitrile). 805 (235000) 746
(91000), 440 (4600) 354 (13000), 304
(8000), 252 (5300) The absorption spectrum of compound () in poly-N-vinylcarbazole film is shown in Figure 1.
The spectral sensitivity spectrum of vinyl carbazole film is shown in FIG. The amount of compound () is poly-N
- 1.5 mg per gram of vinylcarbazole.
For comparison, FIG. 3 shows the absorption spectrum in dichloromethane of a pyrylium compound having the following chemical structure described in the above-mentioned Research Disclosure.

As can be seen from these drawings, the compound of the present invention has substantially no absorption in the visible region and is substantially colorless and transparent, and the photoconductor containing it as a sensitizer has a far-red to near-red sensitizer. Have sensitivity to the outside. Meanwhile, research
Photoconductors containing the compounds described in disc closures have sensitivity in the far-infrared region, but as shown in Figure 3, all of these compounds have absorption in the visible region, so these compounds are included as sensitizers. The photoconductor is colored.

Example 2 2,6-di-t-butyl-4-[5-(2,6
-Di-t-butyl-4H-thiopyran-4-ylidene)-penta-1,3-dienyl]-thiopyrylium perchlorate [compound ()] synthesis method by [Production method 2] 2,6-di-t -Butyl-4-methylthiopyrylium perchlorate (compound) 0.03g and 1,
0.1 g of 1,3,3-tetraethoxypropane [compound (2)] was dissolved in 0.3 ml of acetic acid in a test tube, 0.2 ml of pyridine was added, and the mixture was heated on an oil bath at 125° C. for 10 minutes.

After cooling, 20 ml of diethyl ether was added to precipitate crystals. The crystals were filtered and recrystallized from ethanol to obtain 0.015 g of crystals with a melting point of 232°C.

The infrared absorption spectrum and electronic spectrum of this product were the same as those obtained in Example 1.

Usage Example 1 1 g of poly-N-vinylcarbazole and 1.5 mg of the compound () were dissolved in 10 g of 1,2-dichloroethane, and coated on an aluminum-deposited polyester film using a rod bar.

A photoreceptor with a photoconductive layer was produced by drying at 55°C for one day. The thickness of the photoconductive layer was approximately 2 μm. Since this photoconductive layer is colorless and transparent to visible light, a photoreceptor in which this photoconductive layer is provided on an aluminum vapor-deposited layer has
It appears as if it were an aluminum vapor-deposited layer without a photoconductive layer.

This photoreceptor was charged to +400V 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 5 lux to increase its surface potential.
The exposure amount was obtained by determining the time (seconds) it took for the voltage to reach 200V. The result was E1/2 = 25 lux seconds.

Embodiments of the present invention are shown below.

(1) The thiopyrylium salt according to claim 1, wherein Z is an anion of a strong acid with a pKa of 5 or less.

(2) The thiopyrylium salt according to claim 1, wherein the anion is a chloride ion, bromide ion, perchlorate ion, tetrafluoroborate ion, p-toluenesulfonate ion, or trifluoroacetate ion.

(3) The method for producing a thiopyrylium salt according to claim 2 or 3, wherein Z is an anion of a strong acid with a pKa of 5 or less.

(4) Thiopyrylium salt according to claim 2 or 3, wherein the anion is chloride ion, bromide ion, perchlorate ion, tetrafluoroborate ion, p-toluenesulfonate ion, or trifluoroacetate ion. manufacturing method.

(5) 1-phenylamino-3-phenylimide
2. The method for producing a thiopyrylium salt according to claim 2, wherein the acid that forms a salt with 1-propene is an acid with a pKa of 4 or less.

(6) 1-phenylamino-3-phenylimide
The method for producing a thiopyrylium salt according to claim 2, wherein the acid that forms a salt with 1-propene is hydrochloric acid, hydrobromic acid, or sulfuric acid.

(7) The method for producing a thiopyrylium salt according to claim 2, wherein the reaction is carried out in a carboxylic anhydride in the presence of a base.

(8) The method for producing a thiopyrylium salt according to embodiment (7), wherein the base is an amine.

(9) Embodiment in which the carboxylic anhydride is acetic anhydride
(7) Method for producing thiopyrylium salt.

(10) A method for producing a thiopyrylium salt according to claim 2, wherein the reaction is carried out in an amine.

(11) The method for producing a thiopyrylium salt according to claim 3, wherein the compound () is 1,1,3,3-tetraethoxypropane.

(12) The method for producing a thiopyrylium salt according to claim 3, wherein the reaction is carried out in a carboxylic acid or carboxylic anhydride in the presence of an amine.

(13) The method for producing a thiopyrylium salt according to embodiment (12), wherein the carboxylic acid is acetic acid.

(14) The method for producing a thiopyrylium salt according to embodiment (12), wherein the carboxylic anhydride is acetic anhydride.

[Brief explanation of drawings]

Figure 1 shows the poly-
Absorption spectrum in N-vinylcarbazole film. FIG. 2 is a spectral sensitivity spectrum of a poly-N-vinylcarbazole film containing the thiopyrylium salt of the present invention as a sensitizer. FIG. 3 is an absorption spectrum of a known pyrylium compound in dichloromethane.

Claims (1)

[Claims] 1. 2,6-di- represented by the chemical structural formula ()
t-Butyl-4-[5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene) penta-
1,3-dienyl]thiopyrylium salt. Here, Z represents an anion. 2 2,6-di- expressed by chemical structural formula ()
t-Butyl-4-methylthiopyrylium salt (Z represents an anion), 1-phenylamino-3-phenylimide-
2,6-di-t-butyl-4-[5-(2, 6-di-t-butyl-4H
-thiopyran-4-ylidene) penta-1,3-
Production method of dienyl thiopyrylium salt 3 2,6-di- expressed by chemical structural formula ()
t-Butyl-4-methylthiopyrylium salt (Z represents an anion) and 1,1,3,3- shown by the chemical structural formula ()
A chemical structural formula () characterized by reacting with tetraalkoxypropane (RO) ₂ CHCH ₂ CH(OR) ₂ () (R is an alkyl group having 1 to 4 carbon atoms)
2,6-di-t-butyl-4-[5
-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]thiopyrylium salt production method