JPH0314011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel dichlorostyrene derivative and a method for producing the same. The dichlorostyrene derivative of the present invention is a novel compound that has not been described in any literature, and is represented by the following formula. 4-Hydroxy-β,β-dichlorostyrene can be hydrolyzed to produce p-hydroxyphenylacetic acid, p-hydroxyphenylacetic acid, which is important as a pharmaceutical intermediate.
-Hydroxyphenylacetamide etc. can be easily derived. Therefore 4-hydroxy-β,β-
Dichlorostyrene is extremely valuable as a raw material for the synthesis of p-hydroxyphenylacetic acid, p-hydroxyphenylacetic acid amide, and the like. The only literature on converting phenyltrichloromethylcarbinol derivatives to β,β-dichlorostyrene derivatives is Angew.Chem・Int.Ed, Engl.
16, 57-58 (1977). However, this document does not consider any compounds having chemically active substituents on the benzene nucleus. Therefore, it is extremely difficult to predict how 4-hydroxyphenyltrichloromethylcarbinol, which has a chemically active hydroxyl group, will react. Moreover, the method described in the above document requires the use of mercury in the electrode, which is currently causing problems in terms of pollution and toxicity, and whose use is on the verge of being discontinued; the current efficiency is extremely poor and it cannot be used economically; The real yield of
It also has drawbacks in terms of manufacturing, such as being about 80%. In contrast, according to the method of the present invention,
4-Hydroxy-β,β-dichlorostyrene can be produced safely, easily, and in high yield by electrolytically reducing 4-hydroxyphenyltrichloromethylcarbinol, which can be easily obtained from various raw materials and manufacturing methods. can do. 4- used as starting material in the present invention
Hydroxyphenyltrichloromethylcarbinol is a known compound and can be easily obtained, for example, by addition reaction of chloral to phenol, or from p-hydroxybenzaldehyde and chloroform by phase transfer catalyst or electrolytic method. . The electrolytic reduction reaction of the present invention is carried out in an organic solvent or a water-organic solvent under acidic conditions. Organic solvents include alcohols such as methanol and ethanol,
Ethers such as dioxane and methyl cellosolve,
Solvents that dissolve water to some extent and are inert during electrolysis are used, such as acetonitrile and dimethylformamide. In order to maintain acidic conditions, for example, all kinds of inorganic acids and organic acids can be used, but mineral acids such as hydrochloric acid and sulfuric acid, and organic acids such as benzenesulfonic acid and toluenesulfonic acid are usually preferred. In the present invention, the supporting electrolyte is not particularly limited, and any acid used to maintain acidity can be used as the supporting electrolyte, or hydrochloric acid of a tertiary amine such as tetraethylammonium chloride, tetramethylammonium chloride, etc. Salts, salts such as sulfates, quaternary ammonium salts such as para-toluenesulfonic acid tetraethylammonium salt, para-toluenesulfonic acid tetramethylammonium salt, perchloric acid tetramethylammonium salt, sodium hydroborofluoride, hydroborofluoric acid Usual supporting electrolytes such as hydroborofluoride salts such as tetramethylammonium salts, alkali metal salts such as benzenesulfonic acid and toluenesulfonic acid, and salts of other alkali metals and alkaline earth metals can be used. The amount of supporting electrolyte to be used can be selected from a wide range, but preferably the amount of raw material 1
The amount may range from about 0.01 to 10 moles. As the electrode material, ordinary electrodes such as carbon, platinum, titanium, iron, stainless steel, nickel, and lead can be used. Taking economic efficiency into consideration, a preferable example is to use lead for the cathode and carbon for the anode. The electrode may be a constant current electrolyzer or a constant potential electrolyzer. Although the present invention does not necessarily require a diaphragm,
When a diaphragm is used, a polymer diaphragm, an ion exchange membrane, a glass filter, a clay plate, or the like can be used as the diaphragm. The reaction temperature is preferably in the range of 10 to 70°C, but other temperatures are also possible. More preferably 20~60℃
is within the range of The current density is not particularly limited, but from the viewpoint of production efficiency, reaction time, yield, etc.
-500 mA/ ^cm2 , preferably 50-300 mA/ ^cm2 . The target compound of the present invention can be easily separated and purified from the reaction mixture by conventional methods such as extraction, concentration, distillation, recrystallization, and column chromatography. The present invention will be explained below with reference to Examples. Example 1 10 ml of concentrated hydrochloric acid, 2.5 g of paratoluenesulfonic acid tetraethylammonium salt, and 5.5 g of triethylammonium chloride are dissolved in 60 ml of ethanol, and this solution is placed in an anode chamber and a cathode chamber separated by a diaphragm. 10 mmol of parahydroxyphenyltrichloromethylcarbinol was added to the cathode chamber, and constant current electrolysis was performed using lead as the cathode and carbon as the anode.
After energizing 5F/mol, add catholyte to 200ml of water and add 50ml
After extraction was performed four times with hexane, the hexane extract was dried over anhydrous magnesium sulfate. After distilling off the solvent, the residue is separated and purified using a silica gel column, resulting in parahydroxy-β,β-dichlorostyrene.
Obtain 1.80g. Yield 95.2%, mp90~91℃. IR (cm ^-1 ) 3370, 1604, 1500, 1442, 1375,
1235, 1180, 1109, 909, 873, 821, 682 Example 2 50 ml of methanol containing 3% sulfuric acid is placed in an anode chamber and a cathode chamber separated by a diaphragm. Furthermore, 2.415 g of parahydroxyphenyltrichloromethylcarbinol is added to the cathode chamber. Constant current electrolysis was performed using lead as the anode and cathode. The reaction temperature was maintained at 45 to 50° C., and the same treatment as in Example 1 was performed after applying a current of 3 F/mol, to obtain 1.83 g (yield: 96.8%) of the target product. Example 3 50 ml of a methanol solution containing 3% sulfuric acid and 20% water is placed in an anode chamber and a cathode chamber separated by a diaphragm, and 2.415 g of parahydroxyphenyltrichloromethylcarbinol is added to the cathode chamber. Constant current electrolysis was performed using lead as the anode and cathode. reaction temperature
The mixture was maintained at 40 to 45° C., and the same treatment as in Example 1 was performed after applying a current of 3F/mol to obtain 1.79 g (yield: 94.7%) of the desired product. Example 4 50 ml of acetonitrile containing 3% sulfuric acid is placed in an anode chamber and a cathode chamber separated by an ion exchange membrane, and 2.415 g of parahydroxyphenyltrichloromethylcarbinol is added to the cathode chamber. Constant current electrolysis is performed at a temperature of 50 to 55° C. using lead as an anode and a cathode, and after applying a current of 3 F/mol, the same treatment as in Example 1 is performed to obtain 1.84 g (yield: 97.4%) of the target product.

Claims (1)

[Claims] 1 formula 4-hydroxy-β,β-dichlorostyrene represented by 2 formulas 1. A method for producing 4-hydroxy-β,β-dichlorostyrene, which comprises electrolytically reducing 4-hydroxyphenyltrichloromethylcarbinol. 3. The method according to claim 2, wherein the electrolytic reduction is carried out under acidic conditions. 4. The method according to claim 2 or 3, wherein the electrolytic reduction is carried out at 10 to 70°C.