JPH03141236A - Production of 2,5-disubstituted hydroquinones - Google Patents

Abstract

PURPOSE:To produce the objective compound in high purity and yield by performing the reaction in a chlorinated solvent or aromatic monocyclic solvent when a 2-substituted hydroquinone is reacted with a tertiary alcohol in the presence of an acid to selectively alkylate the 5 position of the 2-substituted hydroquinone. CONSTITUTION:A compound of formula I (R<1> is an organic group residue; n and a are integers of 0-3) is reacted with 4-6 times moles of a tertiary alcohol in the presence of an acid (e.g. sulfuric acid) in a chlorinated solvent or aromatic monocyclic solvent at 20-40 deg.C to prepare a compound of formula II (R<2> is 4-15C tertiary alkyl). The tertiary alcohol is most preferably t-butylalcohol. The chlorinated solvent is preferably methylene chloride, chloroform, etc., and the aromatic monocyclic solvent is preferably chlorobenzene. The solvent is suitably employed in an volume of 1.5-4.0l per mole of the compound of formula I. The prepared compound of formula II is used as an anti-fogging agent for silver halide photosensitive materials.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to particularly high-purity 2,5-disubstituted hydroquinones among substituted hydroquinone compounds used as antifoggants for silver halide photographic light-sensitive materials. The present invention relates to a method for producing with good yield.

[Conventional technology]

Conventionally, 2,5
As a method for synthesizing -disubstituted hydroquinones, a method is generally known in which a substituted or unsubstituted hydroquinone is alkylated using an alcohol or an olefin in the presence of an acid.

For example, hydroquinone and 2-methylpentene are reacted in a methanol or acetic acid solvent in the presence of a Lewis acid catalyst such as concentrated sulfuric acid or phosphoric acid, and 2°5-bis(1°, 1
A method for synthesizing (°-dimethylbutyl)hydroquinone has been reported (Japanese Unexamined Patent Publication No. 1983-93928).

Additionally, a method has been reported in which 2,5-di(1)octylhydroquinone is synthesized by reacting hydroquinone and 2,4,4-trimethylpentene in an ethylene glycol solvent using concentrated sulfuric acid as a catalyst (West German Publication Patent No. 2,
544.904 specification).

Furthermore, hydroquinone and 3.7.11-1-tmethyldodecane-3-ol were reacted in methylcellosolve, ethyl acetate, or l-butanol solvent using concentrated sulfuric acid as a catalyst, and 2.5-bis-(lxtyl A method for synthesizing -1,5,9-)limethyldenyl)hydroquinone has also been reported (Japanese Unexamined Patent Publication No. 1982-29,637).

However, when trying to apply these methods to the production of 2,5-disubstituted hydroquinones using 2-substituted hydroquinones as raw materials, 2゜6-disubstituted hydroquinone, which is an isomer of 25-disubstituted hydroquinone, 2,5-disubstituted hydroquinones are produced at a ratio of 8 to 18% and have similar physical properties, making it difficult to isolate them by distillation, recrystallization, etc. However, there is a problem in that the amount of energy decreases significantly.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide a method for synthesizing highly purified 2,5-disubstituted hydroquinones in high yield by selectively alkylating the 5-position of 2-substituted hydroquinones.

[Means to solve the problem]

The present invention involves producing 2,5-disubstituted hydroquinones by reacting 2-substituted hydroquinones represented by the following general formula (1) with a tertiary alcohol in the presence of an acid.
It is characterized in that the reaction is carried out in a chlorinated solvent or an aromatic monocyclic solvent.

H H (wherein Ro is an organic residue, n is an integer from 0 to 3, a is 0
represents an integer of 3 to 3, preferably 1 to 2, and when a is plural, the plural R1s may be the same or different, and may form a carbocyclic ring.

R1 represents a tertiary alkyl group having 4 to 15 carbon atoms.

) The present invention will be explained in detail below.

-C In formulas (1) and (n), the substituent represented by R1 is an organic residue and is not particularly limited; , pentadecyl), aryl groups (e.g. phenyl), alkyloxy groups (e.g. octyloxy, dodecyloxy), or aryloxy groups (e.g. substituted phenyloxo), acylamino groups (e.g. dodecanoylamino, hexadecanoylamino) , carbamoyl groups (e.g. N-octylcarbamoyl, N,N-dihexylcarbamoyl), sulfonamido groups (e.g. octylsulfonylamino, hexadecylsulfonylamino), sulfamoyl groups (N-octylcarbamoyl, N.

N-dioctylsulfamoyl) and the like.

Ill to the above substituted phenyl group, substituted phenyloxy group
The number of carbon atoms in the substituent group is 1 to 30, preferably 1
The number is between 20 and 20. Further, when the substituent contains an aromatic ring, the number of carbon atoms in the substituent is 6 to 30, preferably 6 to 20.

R2 in the general formula (n) represents a tertiary alkyl group having 4 to 15 carbon atoms, preferably 4 to 8 carbon atoms, and rz
``Tertiary alcohol derived from 5 specifically includes t-butyl alcohol, t-pentanol, t-octatool,
Preferred is t-pentadecanol, most preferably t-butyl alcohol. Note that a corresponding alkylene may be used in place of the tertiary alcohol.

Next, specific examples of the compound represented by the general formula (n) that can be synthesized according to the present invention are shown below, but the present invention is not limited thereto.

(Margin below) H NHCOCHC4H.

2H5 6H13 H NHCOCIIH23 H NHCO07H15 H NHS02C8HI7 H H H NHCOC4H9 H Next, '! of the 2,5-disubstituted hydroquinones of the present invention! !
The reaction conditions in the production method will be explained.

Among the solvents used in the present invention, "C" is methylene chloride, chloroform, carbon tetrachloride, 1.2-dichloro+1ethane, 1.1-dichloroethane, 1.1.i
Mention may be made of l-dichloroethane, preferably methylene chloride, chloroform. Examples of the aromatic monocyclic solvent include benzene, toluene, xylene, chlorobenzene, anisole, etc., and chlorobenzene is preferred. These solvents are appropriately selected depending on the type of raw material compound used.

use? The carrier star is 1.01 to 10ff, preferably 1.01 to 10ff per mole of 2-substituted hydroquinone.
51-7f, 4. It is ox.

The amount of tertiary alcohol to be used is 3.0 to 10 times the mole of the 2-substituted hydroquinone, preferably 4 to 6 times the mole.

Examples of the acid catalyst include acid catalysts such as sulfuric acid, phosphoric acid, p-toluenesulfonic acid, and methanesulfonic acid, with sulfuric acid being preferred.

The amount of the catalyst used is 4.5 to 15 times the mole of the 2-substituted hydroquinone, preferably 6 to 9 times the mole of the 2-substituted hydroquinone.
It is twice the mole.

The reaction temperature in the present invention is 10°C to 50°C, preferably 20°C to 40°C, and is appropriately selected depending on the raw material and the type of compound I. Reaction time is 4 to 8 hours.

As a treatment after the completion of the reaction, approximately twice the volume of water as the reaction solvent and an extraction solvent (for example, ethyl acetate) are added to the reaction product, and after heating at 50 ° C. to 60 ° C. for 1 hour,
The organic layer is washed repeatedly with water to make it neutral. Then there is R
After distilling off the solvent, the target compound can be isolated by recrystallization or purification by column chromatography.

[Function] The present invention allows 2-substituted hydroquinones to react with a tertiary alcohol in the presence of an acid to produce 2,5-disubstituted hydroquinones using a chlorinated refrigerant or an aromatic
By reacting in a cyclic solvent, selective altolation of the 5-position of 2-substituted hydroquinones can be performed in high yield and with high purity, resulting in the formation of 2,6-disubstituted hydroquinones, which are violet compounds. It has been discovered that the amount of by-products such as these can be significantly reduced.

Although this reaction mechanism is not clear, the sulfate ester intermediate of 2,5-disubstituted hydroquinones is more specific in the solvent of the present invention than the sulfate ester intermediate of 2,6-disubstituted hydroquinones. Selective alkylation at the 5-position of 2-substituted hydroquinones by selectively producing only the sulfate ester intermediate of 2,5-disubstituted hydroquinones due to their low solubility and/or high stability in It is thought that this will be done.

Specific examples of 2,5-disubstituted hydroquinones, which are typical compounds, are shown below, but the present invention is not limited thereto.

[Example 1] Synthesis of 5-(1)-butyl-2-(5-dodecanoylaminohensyl)-hydroquinone (synthesis of exemplary compound (1)) 2-(3-dodecanoylaminohensyl)-hydroquinone 10 g (0,025 mol) and 9.3 g (0,125 mol) of (t)-butyl alcohol were added to 50 m6 of chlorobenzene. 95% while stirring under water cooling
Sulfuric acid10. 6 ml (0° 189 mol) was added dropwise over 15 minutes while controlling the internal temperature to be 30° C. or lower. After stirring at 30°C to 35°C for 5 hours, water 100%
IIIl, ethyl acetate 100III! ! and 50℃
Stir for 1 hour at 41! continued.

At this time, when the reaction product was measured by high performance liquid chromatography, the peak area intensity of the target 2,5-disubstituted hydroquinone was 95%, whereas 2
．． That of 6-disubstituted hydroquinone was 1.2%.

The organic layer consisting of ethyl acetate and chlorobenzene was washed three times with water to make it neutral, dried over anhydrous sodium sulfate, and then the solvent was distilled off under reduced pressure.

By recrystallizing the oil with a mixed solvent of 5 ml of ethyl acetate and 80 me of n-hexane, the desired 5
(t)-Butyl-2-(5-dodecanoylaminobenzyl)-hydroquinone 9.2 g (melting point 143-144
°C) was obtained. Yield: 80.7%. As a result of purity measurement by high performance liquid chromatography, the peak area intensity was 99.
It was 4%.

High performance liquid chromatography measurement conditions: 25 cm x O, 46 cm φ TMS column 1 to 112 i ・Liquid A: methanol/dioxane/water/phosphoric acid/triethylamine = 50/47/310°210.2 (vo
1%) ・Benj,: Water/phosphoric acid/triethylamine-100
10.210.2 (vo 1%) Flow 51: 1. Oml/min.

Detection wavelength: 290 nm [Comparative Example] Exemplary compound (1) synthesized in Example 1 was synthesized as follows using a conventional method.

2-(3-dodecanoylaminobenzyl)-hydroquinone 20 g (0.05 mol), ~t-butanol I8
．． 5g (0.25 mol) and ethyl acetate/lz80m
7! 21.1 ml of 95966M acid (0,
375 mol) was added dropwise over 30 minutes, and the mixture was stirred at 35°C to 38°C for 4 hours.

When the reaction product was subjected to high performance liquid chromatography measurement, the peak area intensity of 2,5-disubstituted hydroquinone was 80.3%, while that of 26-di-1m hydroquinone was 13.6%. Further, 100ml of ethyl acetate was added to the reaction mixture, and the mixture was washed with water for 3 times.
After several times, ethyl acetate was distilled off under reduced pressure. The remaining oil was dissolved in 16m6 of ethyl acetate and 80m6 of n-hexane/
It was dissolved in a mixed solvent with and recrystallized. Furthermore, it was recrystallized with a mixed solvent of 18 ml of ethyl acetate and 72 mA of n-hexane to obtain 9.1 g of Exemplified Compound (1). Yield is 40
．． 5%. As a result of a purity test by high performance liquid chromatography (measurement conditions are the same as in Example 1), the peak area intensity was 99.1%.

In addition, in this comparative example, methanol, acetic acid, 1-butanol, ethylene glycol, and methyl cellosolve were used as solvents in place of ethyl acetate, and the reaction was carried out in the same manner as above, but the isomer 2,6-disubstituted hydroquinone was ~
It was produced as a by-product at a rate of 18%.

[Example 2] Synthesis of 5-(t)-butyl-2-[3,5-di(2-functional-y-ylhexanoylamino)benzylco-hydroquinone (synthesis of exemplified compound (5)) 2-(35 10 g (0.025 mol) of -di(2-ethylhexanoylamino)hensiltohydroquinone and 9.3 g (0.125 mol) of (1)-butyl alcohol were mixed in methylene chloride 5
0111, and while cooling with water and stirring, add 95% sulfuric acid 1.
O96Cl (0,189 mol) was added dropwise over 20 minutes while controlling the internal temperature to 30° C. or lower.

After stirring at 30°C to 35°C for 4.5 hours, add 100ml of water.
ff, add 200sZ of ethyl acetate, and heat at 50°C to 55°C.
Stirred at ℃ for 1 hour.

The ethyl acetate-methylene chloride layer in the reaction product was washed with water three times to make it neutral, dried over anhydrous sodium sulfate, and then the solvent was distilled off under reduced pressure.

The obtained oil was purified by column chromatography using a mixed solvent of ethyl acetate and n-hexane in a ratio of 1:3 as a developing solvent, and the solvent was distilled off under reduced pressure.

Furthermore, the obtained oil was dissolved in 30 ml of ethyl acetate, washed with hydrosulfide water, and then washed with water for 2 times.
After drying with anhydrous sodium sulfate, ethyl acetate was completely distilled off under reduced pressure, and 5-(t)-butyl-2-(3,5
-8.8g of powder of di(2-ethylhexanoylamino)hensyl-hydroquinone was obtained. Yield 78.3%.

As a result of purity measurement by high performance liquid chromatography, the peak area intensity was 99.5%.

〔Effect of the invention〕

According to the present invention, when synthesizing 2,5-disubstituted hydroquinones by alkylating 2-substituted hydroquinones, the by-product rate of 2,6-disubstituted hydroquinones, which are isomers, can be suppressed to within 2%. 2. of high purity.
Since 5-disubstituted hydroquinones can be produced in high yield, it is possible to achieve particularly high efficiency in the production of antifoggants for silver halide photographic light-sensitive materials.

Claims (1)

[Claims] (1) Reacting a 2-substituted hydroquinone represented by the following general formula (I) with a tertiary alcohol in the presence of an acid,
In producing 2,5-disubstituted hydroquinones represented by the following general formula (II), 2,5-disubstituted hydroquinones are reacted in a chlorinated solvent or an aromatic monocyclic solvent. Production method. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R^1 is an organic residue, n is an integer from 0 to 3, and a is from 0 to Represents an integer of 3, and when a is multiple, multiple R^1
may be the same or different and may form a carbon ring. R^2 represents a tertiary alkyl group having 4 to 15 carbon atoms. )