JP2000119208A - Anthracene derivative and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound in a high yield by reacting an anthraquinone-based compound with a specific amount of hydrosulfite in a reaction medium containing an alcohol, keeping at a specific temperature and a specific pH and reacting with a specific alkylation agent. SOLUTION: This compound of formula II (e.g. 2-methyl-9,10- dimethoxyanthracene, 2-methyl-9,10-diethoxyanthracene or the like) is obtained by subjecting (B) an anthraquinone-based compound (e.g. 2-methylanthraquinone) of formula I (R1 is methyl or ethyl; R2 and R3 are each H or lower alkyl) with (C) 1.25-2 mol times of the component B of hydrosulfite to reducing reaction in a reaction medium containing an alcohol (e.g. methanol, ethanol or the like), preferably at 0-50 deg.C, keeping at a temperature below 50 deg.C and >=pH 9 and reacting with an alkylation agent selected from dimethylsulfuric acid and diethylsulfuric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to 2-ethyl-9,
The present invention relates to a method for producing a 9,10-dialkoxyanthracene compound such as 10-dimethoxyanthracene. 2-ethyl-9,10-dimethoxyanthracene is disclosed in, for example, Japanese Patent Publication No. 49-36260 and Japanese Patent Application Laid-Open No. 10-2139.
In JP-A No. 05, it is known as a sensitizer for a photosensitive composition or a resist composition. The present invention is also directed to novel 9,10-dialkoxyanthracene compounds themselves which are useful as such sensitizers.

[0002]

2. Description of the Related Art In the production of 9,10-dialkoxyanthracene compounds, a method for reductively alkylating an anthraquinone compound has been known.
Seitz et al., Synthesis, 686-688 (1986)
A method has been reported in which a methylene chloride two-phase system uses hydrosulfite as a reducing agent and methyl iodide as an alkylating agent. However, this method is not sufficiently satisfactory as an industrial production method, for example, there is a concern about environmental pollution by a halogen-based solvent, and furthermore, an expensive alkylating agent is used.

[0003] Also, TR Criswell et al., J. Org.
Chem., 39 , 770-774 (1974) reports a method using sodium borohydride as a reducing agent. However, this method requires that the reducing agent is expensive and
Since the reduction may proceed too much and the reaction may proceed to the anthrone derivative or the anthracene ring, it is still not sufficiently satisfactory as an industrial production method.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to produce anthracene derivatives by an industrially satisfactory method.

The inventors of the present invention have conducted intensive studies to achieve such an object, and as a result, have used hydrosulfite (Na ₂ S ₂ O ₄ : also called sodium dithionite) as a reducing agent and an alkylating agent. Using dimethyl sulfate or diethyl sulfate, a method for reductive alkylation of an anthraquinone compound was found, and further, this method was carried out in an alcohol medium by adjusting the charge ratio of hydrosulfite to anthraquinone compound, and the temperature and pH in the alkylation reaction. It has been found that the anthracene derivative can be obtained in good yield by performing the treatment appropriately, and the present invention has been completed.

[0006]

That is, the present invention provides the following formula (I)

[0007]

Wherein R ¹ represents methyl or ethyl;
R ² and R ³ each independently represent hydrogen or lower alkyl) when producing an anthracene derivative represented by the following formula (II):

[0009]

(Wherein R ² and R ³ have the same meanings as above), which is reacted with 1.25 to 2 moles of hydrosulfite, and then reacted at 50 ° C. or lower. It is intended to provide a method of reacting with an alkylating agent selected from dimethyl sulfate and diethyl sulfate while maintaining the temperature at pH 9 or more.

Certain of the anthracene derivatives of the formula (I) are novel. Therefore, the present invention also provides an anthracene derivative represented by the following formula (Ia).

[0012]

Wherein R ¹ represents methyl or ethyl;
^{When 1} is methyl, R ²¹ and R ³¹ independently represent lower alkyl; when R ¹ is ethyl, ^one of R ²¹ and R ³¹ represents lower alkyl, and the other represents hydrogen or lower alkyl.

[0014]

DETAILED DESCRIPTION OF THE INVENTION In the formulas (I) and (Ia),
When R ² , R ³ , R ²¹ and / or R ³¹ are lower alkyl, such lower alkyl includes methyl, ethyl,
Propyl, isopropyl, butyl, isobutyl, sec-
Examples thereof include those having about 1 to 6 carbon atoms, such as butyl, tert-butyl, pentyl and hexyl.

In the present invention, when the anthraquinone compound represented by the formula (II) is subjected to reductive alkylation, hydrosulfite is used as a reducing agent. The amount of hydrosulfite is in the range of 1.25 to 2 mol times, preferably 1.4 mol, based on the anthraquinone compound of the formula (II).
It is in the range of ~ 1.7 mole times. If the amount of hydrosulfite is too small, the residual amount of the anthraquinone-based compound of the formula (II), which is a raw material, increases, and if the amount of hydrosulfite is too large, reduction proceeds too much to produce by-products.

This reaction is carried out in a medium containing alcohol, and as the alcohol, methanol, ethanol, isopropanol or the like is used. Particularly, methanol or ethanol is preferable. The medium in this reaction may be alcohol alone, but may be mixed with another medium, for example, water. This reduction reaction is usually carried out under basic conditions, and a basic compound such as sodium hydroxide or potassium hydroxide is added to make the basic condition, but the basic compound is added in the form of an aqueous solution. Then, it becomes a mixed medium of alcohol and water. This reduction reaction is usually performed at 0 to 50 ° C.
It can be performed at a temperature of the order of magnitude.

After the reduction of the anthraquinone compound of the formula (II), an alkylation reaction is carried out. At this time, the reducing agent used in the previous reduction reaction may remain in the reaction system as it is. The alkylating agent used here is dimethyl sulfate or diethyl sulfate. Although the amount of the alkylating agent varies depending on other reaction conditions, it is usually used in an amount of at least 3 moles, preferably at least 4 moles, based on the anthraquinone compound of the formula (II). This alkylation reaction is
It can be carried out in a medium containing the same alcohol as the previous reduction reaction.

[0018] The alkylation reaction is performed at a temperature of 50 ° C or less. When the reaction temperature increases, the stirring state of the reaction system deteriorates, and side reactions easily occur. When the reaction temperature is lowered, the progress of the reaction is slowed. Therefore, usually, a temperature of 10 ° C. or higher is adopted, and it is advantageous to set the temperature to normal temperature, for example, 20 ° C. or higher. In this reaction, a basic condition of pH 9 or more is employed. PH in alkylation reaction
Is low, the remaining raw materials become noticeable. Preferably pH 9-12, more preferably pH 9-10
And the reaction is carried out. In order to have basic conditions,
Basic compounds such as sodium hydroxide and potassium hydroxide are used. These basic compounds are usually added to the system in the form of an aqueous solution.

The time of the alkylation reaction may vary depending on the reaction temperature and the like, but is generally about 2 to 24 hours. After completion of the reaction, the anthracene derivative represented by the formula (I) can be obtained by performing ordinary post-treatment operations such as solvent extraction, concentration, and recrystallization.

Table 1 shows typical examples of the anthraquinone compound of the formula (II) as a raw material and the anthracene derivative of the formula (I) obtained therefrom. Formula (I)
Among the anthracene derivatives of the above, those corresponding to the formula (Ia) are indicated as (Ia) in the remarks column of Table 1.

[0021]

[Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Formula (II) Formula (I) Remarks ━━━━━━━━━ Anthraquinone 9,10-dimethoxyanthracene 9,10-diethoxyanthracene 2-methylanthraquinone 2-methyl-9,10-dimethoxyanthracene 2-methyl -9,10-diethoxyanthracene (Ia) 2-ethylanthraquinone 2-ethyl-9,10-dimethoxyanthracene 2-ethyl-9,10-diethoxyanthracene (Ia) 2-fluoroanthraquinone 2-fluoro-9,10 -Dimethoxyanthracene 2-fluoro-9,10-diethoxyanthracene (Ia) 2-butylanthraquinone 2-butyl-9,10-dimethoxyanthracene 2-butyl-9,10-diethoxyanthracene (Ia) 2-tert-butyl Anthraquinone 2-tert-butyl -9,10-dimethoxyanthracene 2-tert-butyl-9,10-diethoxyanthracene (Ia) 2-pentylanthraquinone 2-pentyl-9,10-dimethoxyanthracene 2-pentyl-9,10-diethoxyanthracene (Ia ) 2-hexylanthraquinone 2-hexyl-9,10-dimethoxyanthracene 2-hexyl-9,10-diethoxyanthracene (Ia) 2,3-dimethylanthraquinone 2,3-dimethyl-9,10-dimethoxyanthracene (Ia) 2,3-Dimethyl-9,10-diethoxyanthracene (Ia) 2,3-Diethylanthraquinone 2,3-Diethyl-9,10-dimethoxyanthracene (Ia) 2,3-Diethyl-9,10-diethoxyanthracene (Ia) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0022]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited by these examples. In the examples,% representing the content is based on weight unless otherwise specified.

Example 1 (Synthesis of 2-ethyl-9,10-dimethoxyanthracene) 2-ethylanthraquinone 65 in 390 kg of methanol
kg (275 mol) were suspended, and 120 kg (840 mol) of a 28% aqueous sodium hydroxide solution was added. 77.5 kg (445 mol) of hydrosulfite was added thereto, and 30
Stirred at ４０40 ° C. for 30 minutes. Next, the pH controller was set to pH 9 to 10, and the pH was adjusted with a 28% aqueous sodium hydroxide solution at a temperature of 40 ± 5 ° C.
175 kg (1,387 mol) of dimethyl sulfuric acid were added over 2 hours. After the addition of dimethyl sulfuric acid, the temperature is further increased
The mixture was stirred at 3 ± 2 ° C. and pH 9 to 10 for 15.5 hours to ripen. PH from the start of dimethyl sulfate addition to the end of ripening
The 28% aqueous sodium hydroxide solution required for the adjustment was 168
kg (1,176 mol). Thereafter, the mixture was diluted with pure water, extracted with toluene and separated, and the toluene layer was washed and concentrated. Methanol was added, and the mixture was cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 2-ethyl-9,10-dimethoxyanthracene corresponding to the following formula.
7.0 kg were obtained. Yield 77.8%.

[0024]

Melting point: 117-119 ° C. ¹ H-NMR δ ppm (CDCl ₃ ): 1.38 (3H, t, J = 7.
_{6Hz, CH 3), 2.86 (} 2H, q, J = 7.6Hz, CH 2), 4.11 (6H, s,
OCH ₃ ), 7.36-7.40 (1H, m, arom.H), 7.45-7.49 (2H, m,
arom.H), 8.05 (1H, m, arom.H), 8.21-8.29 (3H, m,
arom. H).

The obtained 2-ethyl-9,10-dimethoxyanthracene had the same melting point and NMR spectrum as the authentic sample.

Comparative Example 1 (Effect of reaction temperature) 2-ethylanthraquinone 5 in 300 g of methanol
0.0g (0.21 mol) was suspended, and 90.7 g (0.63 mol) of a 28% aqueous sodium hydroxide solution was added. 59.0 g (0.34 mol) of hydrosulfite was added thereto, and the mixture was stirred at 30 to 40 ° C. for 30 minutes. Next, the pH controller was set to a pH of 9 to 10, and the pH was adjusted with a 28% aqueous sodium hydroxide solution at 50 to 60 ° C.
At a temperature of 80.1 g (0.64 mol) of dimethyl sulfate.
Added over time. After the completion of the addition of dimethyl sulfate, the mixture was further stirred at the same temperature and the same pH for 2 hours to be aged. 70.8 g (0.50%) of a 28% aqueous sodium hydroxide solution required for pH adjustment from the start of addition of dimethyl sulfate to the end of ripening was used.
Mol). In this case, the slurry property was poor and the stirring state was poor. After dilution with pure water, extraction with toluene was carried out to separate the layers, and the toluene layer was washed and concentrated to obtain 53.4 g of a concentrated mass. As a result of analyzing the concentrated mass by liquid chromatography, the area ratio between 2-ethyl-9,10-dimethoxyanthracene and by-products 2-ethyl-9-methoxyanthracene and 2-ethyl-10-methoxyanthracene was found to be: , About 1: 1.

Comparative Example 2 (Effect of pH) 2-ethylanthraquinone 5 in 300 g of methanol
0.0g (0.21 mol) was suspended, and 90.7 g (0.63 mol) of a 28% aqueous sodium hydroxide solution was added. 59.0 g (0.34 mol) of hydrosulfite was added thereto, and the mixture was stirred at 30 to 40 ° C. for 30 minutes. Next, the set value of the pH controller was adjusted to pH 8 to 9, and the pH was adjusted with a 28% aqueous sodium hydroxide solution at 50 to 60 ° C.
At a temperature of 109.3 g (0.87 mol) of dimethyl sulfuric acid were added over 2 hours. After the completion of the addition of dimethyl sulfate, the mixture was further stirred at the same temperature and the same pH for 2 hours to be aged. The amount of the 28% aqueous sodium hydroxide solution required for pH adjustment from the start of the addition of dimethyl sulfate to the completion of ripening was 120.0 g (0.1%).
84 mol). Thereafter, the mixture was diluted with pure water, extracted with toluene, and separated. In this case, the remaining raw material, that is, toluene-insoluble matter was large, and this toluene-insoluble matter was suspended in the toluene layer. The toluene layer containing the suspension was washed and concentrated to obtain 28.7 g of a concentrated mass. As a result of analyzing the concentrated mass by liquid chromatography, 2
-Ethyl-9,10-dimethoxyanthracene and raw material 2
The area ratio of -ethylanthraquinone was about 1: 1.

Comparative Example 3 (Effect of Hydrosulfite Charge Ratio) 2-Ethyl anthraquinone 5 in 300 g of methanol
0.0g (0.21 mol) was suspended, and 90.7 g (0.63 mol) of a 28% aqueous sodium hydroxide solution was added. 46.1 g (0.26 mol) of hydrosulfite was added thereto, and the mixture was stirred at 30 to 40 ° C. for 30 minutes. Next, the pH of the pH controller was set to 9 to 10 and the pH was adjusted with a 28% aqueous sodium hydroxide solution at 30 to 40 ° C.
At a temperature of 93.3 g (0.74 mol) of dimethyl sulfate.
Added over time. After the completion of the addition of dimethyl sulfate, the mixture was further stirred at the same temperature and the same pH for 2 hours to be aged. From the start of addition of dimethyl sulfate to the end of ripening, 157.1 g (1.1%) of a 28% aqueous sodium hydroxide solution required for pH adjustment was used.
0 mol). Thereafter, the mixture was diluted with pure water, extracted with toluene, and separated. Also in this case, the toluene-insoluble matter as the remaining raw material was suspended in the toluene layer. After washing the toluene layer containing the suspension, it was concentrated and the concentrated mass was reduced to 35.
1 g was obtained. As a result of analyzing the concentrated mass by liquid chromatography, the area ratio between 2-ethyl-9,10-dimethoxyanthracene and the raw material 2-ethylanthraquinone was determined as follows:
It was about 1: 1.

Comparative Example 4 (Effect of Hydrosulfite Charge Ratio) 2-Ethyl anthraquinone 10 in 400 g of methanol
0 g (0.42 mol) were suspended, and 300 g (2.10 mol) of a 28% aqueous sodium hydroxide solution was added. 295 g (1.69 mol) of hydrosulfite was added thereto, and the mixture was stirred at 30 to 40 ° C for 30 minutes. Next, 214 g (1.70 mol) of dimethyl sulfuric acid was reacted in the same manner as in Comparative Example 3 while the pH controller was set at pH 9 to 10 and the pH was adjusted with a 28% aqueous sodium hydroxide solution. From the start of addition of dimethyl sulfate to the end of ripening, p
The 28% aqueous sodium hydroxide solution required for H
0 g (1.33 mol). Further, the same post-treatment as in Comparative Example 3 was performed to obtain 146 g of a concentrated mass. As a result of analyzing the concentrated mass by liquid chromatography, the area ratio between 2-ethyl-9,10-dimethoxyanthracene and by-products 2-ethyl-9-methoxyanthracene and 2-ethyl-10-methoxyanthracene was found to be: , About 2: 3.

Table 2 shows the main variables and results in Example 1 and Comparative Examples 1 to 4.

[0032]

[Table 2] Example 1 Comparative Example 1 Comparative Example 2 Comparison Example 3 Comparative Example 4 2-ethylanthraquinone 65 kg 50.0 g 50.0 g 50.0 g 100 g (275 mol) (0.21 mol) (0.21 mol) (0.21 mol) (0.42 mol) Hydurosulfite 77.5 kg 59.0 g 59.0 g 46.1 g 295 g (445 mol) (0.34 mol) (0.34 mol) (0.26 mol) (1.69 mol) molar ratio^* 1.6 1.6 1.6 1.2 4.0Alkylation reaction Dimethyl sulfate 175 kg 80.1 g 109.3 g 93.3 g 214 g (1,387 mol) (0.64 mol) (0.87 mol) (0.74 mol) (1.70 mol) 28% NaOH^** 288 kg 161.5 g 210.7 g 247.8 g 490 g (2,016 mol) (1.13 mol) (1.47 mol) (1.73 mol) (3.43 mol) Set pH 9-10 9-10 8-9 9-10 9-10 Addition temperature 40 ± 5 ℃ 50-60 ℃ 50-60 ℃ 30-40 ℃ 30-40 ℃ Aging temperature 33 ± 2 ℃ Same as above Same as above Same as above ───────────────────── ─────────────── Result Yield 77.8% Poor slurry property Remaining raw material Remaining raw material By-products By-products ━━━━━━━━━━━━━ ━━━━━━━━━━━━━━━━━━━━━━━ ^* The molar ratio of hydrosulfite to 2-ethylanthraquinone.^** The amount of 28% NaOH is the sum of the amount charged before the start of the reaction and the amount required for pH adjustment.

Example 2 (2,3-dimethyl-9,10-
Synthesis of dimethoxyanthracene) 5.0 g (0.02 mol) of 2,3-dimethylanthraquinone was suspended in 50 g of ethanol, and 8.5 g (0.064 mol) of a 30% aqueous sodium hydroxide solution was added. Thereto was added 6.2 g (0.036 mol) of hydrosulfite, and the mixture was stirred at 30 to 40 ° C. for 30 minutes. Next, the pH of the pH controller was adjusted to 9 to 10 and 10.7 g (0.085 mol) of dimethyl sulfuric acid was added at a temperature of 40 ± 5 ° C. while adjusting the pH with a 30% aqueous sodium hydroxide solution.
Added over 0 minutes. After the addition of dimethyl sulfate was completed, the mixture was further aged by stirring at a temperature of 33 ± 2 ° C. and a pH of 9 to 2 for 2 hours. From the start of addition of dimethyl sulfate to the end of ripening, p
The 30% aqueous sodium hydroxide solution required for H adjustment was 8.
5 g (0.064 mol). Thereafter, the mixture was diluted with pure water, extracted with toluene and separated, and the toluene layer was washed and concentrated. Methanol was added, and the mixture was cooled and crystallized, and the precipitated crystals were filtered, washed and dried to obtain 4.1 g of 2,3-dimethyl-9,10-dimethoxyanthracene corresponding to the following formula. Yield 72.7%.

[0034]

Melting point: 79-81 ° C. ¹ H-NMR δ ppm (CDCl ₃ ): 2.51 (6H, s, C)
H ₃ ), 4.10 (6H, s, OCH ₃ ), 7.42-7.46 (2H, m, arom.
H), 8.03-8.08 (2H, m, arom.H), 8.24-8.27 (2H, m, ar
om. H). FD-MS: 266 (M ⁺ )

Example 3 (Synthesis of 2-methyl-9,10-diethoxyanthracene) 12.5 g (0.056 mol) of 2-methylanthraquinone
Was suspended in 70 g of ethanol, 25 g (0.19 mol) of a 30% aqueous sodium hydroxide solution and 15.7 g (0.09 mol) of hydrosulfite were added.
Stirred for minutes. Next, the set value of the pH controller is
H9 to 10 and pH with 30% aqueous sodium hydroxide
While adjusting, at a temperature of 40 ± 5 ° C., diethyl sulfate 3
4.7 g (0.23 mol) were added over 30 minutes. After completion of the addition of diethyl sulfate, the mixture was further aged by stirring at the same temperature and the same pH for 2 hours. From the start of addition of diethyl sulfate to the completion of ripening, 20 g (0.15 mol) of a 30% aqueous sodium hydroxide solution was required for pH adjustment. After completion of the reaction, the mixture was diluted with water, extracted with ethyl acetate, the organic layer was washed with water, dried over magnesium sulfate, and concentrated to give 2-methyl-9,10-diethoxyanthracene corresponding to the following formula. 7 g were obtained. Yield 86.9%.

[0037]

Melting point: 54-55 ° C. ¹ H-NMR δ ppm (CDCl ₃ ): 1.61 (3H, t, J = 7.
2Hz, CH ₃ ), 1.63 (3H, t, J = 7.2Hz, CH ₃ ), 2.56 (3H, s,
CH ₃ ), 4.23 (2H, q, J = 7.2Hz, CH ₂ ), 4.24 (2H, q, J = 7.2
Hz, CH ₂ ), 7.24-7.32 (1H, m, arom.H), 7.42-7.46 (2H,
m, arom.H), 8.01 (1H, m, arom.H), 8.21-8.27 (3H,
m, arom. H). FD-MS: 280 (M ⁺ )

Example 4 (Synthesis of 2-ethyl-9,10-diethoxyanthracene) 11.8 g (0.05 mol) of 2-ethylanthraquinone was suspended in 60 g of ethanol. Hereinafter, a reaction using 20 g (0.15 mol) of a 30% aqueous sodium hydroxide solution and 13.9 g (0.08 mol) of hydrosulfite, and 30.8 g (0.20 mol) of diethyl sulfate and 30% sodium hydroxide The reaction using the aqueous solution was carried out according to Example 3. The amount of a 30% aqueous sodium hydroxide solution required for pH adjustment was 20 g (0.15 mol). Example 3
After the same post-treatment as described above, 2-ethyl-
12.0 g of 9,10-diethoxyanthracene was obtained.
Yield 81.6%.

[0040]

Melting point: 55-56 ° C. ¹ H-NMR δ ppm (CDCl ₃ ): 1.38 (3H, t, J = 7.
6Hz, CH ₃ ), 1.62 (3H, t, J = 7.2Hz, CH ₃ ), 1.63 (3H, t,
J = 7.2Hz, CH ₃ ), 2.87 (2H, q, J = 7.6Hz, CH ₂ ), 4.24 (4H,
q, J = 7.2Hz, CH ₂ ), 7.25-7.37 (1H, m, arom.H), 7.42-
7.46 (2H, m, arom.H), 8.04 (1H, m, arom.H), 8.20-
8.28 (3H, m, arom. H). FD-MS: 294 (M ⁺ )

Example 5 (2-tert-butyl-9,10-
Synthesis of diethoxyanthracene) 13.2 g (0.05 mol) of 2-tert-butylanthraquinone was suspended in 70 g of ethanol. Hereinafter, a reaction using 20 g (0.15 mol) of a 30% aqueous sodium hydroxide solution and 13.9 g (0.08 mol) of hydrosulfite, and 30.8 g (0.20 mol) of diethylsulfuric acid and 30 g of diethylsulfuric acid
The reaction using a 3% aqueous sodium hydroxide solution was carried out according to Example 3. The amount of a 30% aqueous sodium hydroxide solution required for pH adjustment was 20 g (0.15 mol). Further, the same post-treatment as in Example 3 was performed to give 2-tert corresponding to the following formula.
-Butyl-9,10-diethoxyanthracene to 14.
0 g was obtained. Yield 86.9%.

[0043]

Melting point: 82-84 ° C. ¹ H-NMR δ ppm (CDCl ₃ ): 1.46 (9H, s, tB)
u), 1.61 (3H, t, J = 7.2Hz, CH ₃ ), 1.63 (3H, t, J = 7.2H
z, CH ₃ ), 4.24 (2H, q, J = 7.2Hz, CH ₂ ), 4.25 (2H, q, J =
_{7.2Hz, CH 2), 7.42-7.46 (} 2H, m, arom. H), 7.53-7.59
(1H, m, arom. H), 8.19-8.27 (4H, m, arom. H). FD-MS: 322 (M ⁺ )

[0045]

The anthracene derivative represented by the formula (I) or (Ia) is useful as a sensitizer in a photosensitive composition such as a resist. According to the present invention, such a useful anthracene derivative is used. Can be produced industrially advantageously.

Claims (6)

[Claims] In a reaction medium containing an alcohol, a compound of the formula (II) (Wherein R ² and R ³ independently represent hydrogen or lower alkyl)
On the other hand, it is characterized by reacting with 1.25 to 2 mole times of hydrosulfite, then maintaining the pH at 9 or more at a temperature of 50 ° C. or less, and reacting with an alkylating agent selected from dimethyl sulfate and diethyl sulfate. , Formula (I) (Wherein R ¹ represents methyl or ethyl, and R ² and R ³
Represents the above-mentioned meaning). 2. The method according to claim 1, wherein the hydrosulfite is used in an amount of from 1.4 to 1.7 mol times based on the anthraquinone compound of the formula (II). 3. The method according to claim 1, wherein the reaction medium is a mixture of alcohol and water. 4. The method according to claim 1, wherein the alkylating agent is used in an amount of at least 3 times the amount of the anthraquinone compound of the formula (II).
3. The method according to any one of 3. 5. The method according to claim 1, wherein the reaction with the alkylating agent is carried out while maintaining the pH at 9 to 10. 6. The formula (Ia) (Wherein, R ¹ represents methyl or ethyl, when R ¹ is methyl, R ²¹ and R ³¹ independently represent a lower alkyl each other, when R ¹ is ethyl, one of R ²¹ and R ³¹ is a lower Anthracene derivative represented by alkyl, and the other represents hydrogen or lower alkyl).