JP3057293B2 - Preparation of phenolic compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to the following general formula [I] useful as an intermediate for synthesizing a developer for heat-sensitive recording or pressure-sensitive recording and other organic industrial subjects. And a method for producing a phenolic compound represented by the formula:

(Wherein R ¹ and R ² represent hydrogen or a lower alkyl group.) “Conventional Techniques and Problems to be Solved by the Invention” A conventional method for producing a phenolic compound represented by the general formula [I] is as follows. Catechols were oxidized at low temperature without catalyst using an equivalent amount of an oxidizing agent, and the resulting oxidation product was reacted with benzenesulfinic acids.

For example, Japanese Unexamined Patent Publication No. 59-95284, p. 720 discloses that 4-methylcatechol and sodium salt of benzenesulfinic acid are prepared by using potassium iron (III) ferricyanide and sodium acetate trihydrate to form 4-methyl-5-phenylsulfonyl. −1,
It has been shown that 2-benzenediol can be produced, and JP-A-63-119451 discloses that catechol is oxidized with potassium iodate, p-toluenesulfinate is added, and 3,4
It has been shown that -dihydroxy-4'-methyldiphenylsulfone can be prepared.

However, all of these conventional methods use a special and expensive oxidizing agent to control the reaction and are expensive, and the method of Japanese Patent Application Laid-Open No. Generated hydrogen cyanide, which was not preferable as an industrial production method.

The present invention has general problems [I] which had various problems as described above.
The purpose of the present invention is to improve the conventional method for producing a phenolic compound represented by the formula:

"Means and Actions for Solving the Problems" The present invention has solved the above-mentioned problems. Oxygen, air, hydrogen peroxide is obtained by using catechol or its nuclear-substituted product as a catalyst with copper chloride, copper acetate or copper acetylacetonate. Phenolic compound represented by the following general formula (I), wherein the phenolic compound is oxidized with an oxidizing agent selected from the group consisting of benzenesulfinic acid and its nucleus-substituted product.

(Wherein R ¹ and R ² represent hydrogen or a lower alkyl group. The lower alkyl group means a straight or branched one having 1 to 4 carbon atoms.) Examples of the catalyst that can be used in the present invention include: Copper chloride,
Examples thereof include copper acetate and copper acetylacetonate. The amount of the catalyst to be used is preferably 1 × 10 ^{-1 to} 5 × 10 ^-3 molar equivalents relative to catechol or a nuclear substitution product thereof, and 3 × 10 ^-3 to 5 × 10 ^-3 .
5 × 10 ⁻³ molar equivalents are particularly preferred. Water, as a solvent,
An organic solvent or an organic solvent containing water can be used.
Examples of the organic solvent include methanol, ethanol, acetone, ethyl acetate, tetrahydrofuran, dioxane and the like. Oxygen, air, hydrogen peroxide, or the like can be used as the oxidizing agent. In the case of hydrogen peroxide, the amount used is 1.0 to catechol or its nuclear substitute.
-1.2 molar equivalents are preferred, and 1.1 molar equivalents are particularly preferred.

As catechol or its nuclear substitute, catechol,
4-t-butylcatechol, 4-methylcatechol and the like can be mentioned.

Examples of benzenesulfinic acid or its nucleus-substituted product include benzenesulfinic acid and paratoluenesulfinic acid. Benzenesulfinic acid or its nuclear substituent is preferably used in a small excess of 1.0 to 1.2 molar equivalents relative to catechol or its nuclear substituent,
It is particularly preferred to use molar equivalents.

The temperature during the reaction is preferably maintained at 20 to 80 ° C.,
-50 ° C is particularly preferred.

 Hereinafter, the present invention will be described in detail with reference to examples.

“Examples” Example 1 0.8 g (7 × 10 ⁻³ mol) of catechol and 2 g (8 × 10 ⁻³ mol) of sodium paratoluenesulfinate tetrahydrate were dissolved in water, and 0.1 ml of hydrochloric acid was added. Add 1 × 10 ^-3 molar equivalents of copper acetylacetonate as a catalyst and heat to 50 ° C.
Hydrogen peroxide / water (2 ml / 10 ml) was added dropwise over 2 hours.
After completion of the dropwise addition, the mixture was stirred at 50 ° C. for 2 hours. As a result, pale yellow crude crystals were obtained as precipitates. (1.8g) After washing with water, methanol /
Recrystallized from water (6.3ml / 6.3ml) to give 3,4-dihydroxy-4 '
-White crystals of methyldiphenyl sulfone were obtained. (1.46
g) Example 2 Copper acetylacetonate is copper chloride and 0.2 g of sodium paratoluenesulfinate tetrahydrate is initially charged, and the remaining 1.8 g is dissolved in 10 ml of water. The reaction and treatment were carried out in the same manner as in Example 1 except that they were simultaneously dropped. As a result, 1.74 g of crude crystals and 1.61 g of recrystallization were obtained.

Example 3 0.8 g (7 × 10 ⁻³ mol) of catechol and 1.6 g (8 × 10 ⁻³ mol) of sodium benzenesulfinate dihydrate were dissolved in water, and 0.1 ml of hydrochloric acid was added. 1 × 10 ^-3 molar equivalents of copper nate were added, heated to 40 ° C., and hydrogen peroxide / water (1.8 ml / 10 ml) was added dropwise over 2 hours.
After completion of the dropwise addition, the mixture was stirred at 40 ° C. for 1 hour. As a result, ocher crude crystals were obtained as precipitates. (1.46 g) After washing with water, recrystallization from methanol / water (5 ml / 5 ml) gave white crystals of 3,4-dihydroxydiphenyl sulfone. (1.2 g) Example 4 Catechol is 4-methylcatechol and 0.15 g of sodium benzenesulfinate dihydrate was initially charged, and the remaining 1.45 g was dissolved in 10 ml of water. The reaction and treatment were carried out in the same manner as in Example 3, except that they were simultaneously dropped. As a result, 1.95 g of crude crystals and 1.8 g of recrystallized 4-methyl-5-phenylsulfonyl-1,2-benzenediol were obtained.

After Example 5 catechol 0.8g (7 × 10 ^-3 mol) and sodium para-toluene sulfinate tetrahydrate 2.0g of (8 × 10 ^-3 mol) was added hydrochloric acid was dissolved in water, copper chloride 5 × 10 ^- Add ³ molar equivalents and heat to 50 ° C while blowing air into the reaction system.
Stirred for hours. As a result, 1.5 g of crude crystals and 1.41 g of recrystallized 3,4-dihydroxy-4'-methyldiphenylsulfone were obtained.

"Effects of the Invention" The present invention oxidizes catechols and reacts with benzenesulfinic acids to produce a phenolic compound represented by the general formula (I), using copper chloride, copper acetate or copper acetylacetonate as a catalyst. By using as, an inexpensive oxidizing agent such as oxygen, air, and hydrogen peroxide can be used, and the desired phenolic compound can be obtained in a high yield.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuyoshi Endo 54-13 Miyagaya, Nishi-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-59-95284 (JP, A) JP-A-63-119451 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C07C 317/00 C07C 315/00 C07B 61/00 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] Catechol or a nucleus-substituted product thereof is treated with copper chloride, copper acetate or copper acetylacetonate as a catalyst,
A process for producing a phenolic compound represented by the following general formula [I], comprising oxidizing with an oxidizing agent selected from air and hydrogen peroxide, and reacting an oxidation product with benzenesulfinic acid or a nuclear substitution product thereof. (In the formula, R ¹ and R ² represent hydrogen or a lower alkyl group.)