JPH0535232B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing 2-(nitrophenyl)-2-substituted-ethanols. More specifically, ortho- or para-nitro-substituted alkylbenzenes and paraformaldehyde are electrolytically reduced in the presence of a supporting electrolyte, or paraformaldehyde is electrolytically reduced in the presence of a supporting electrolyte, and the resulting reduction product is nitro-substituted. The present invention relates to a method for producing 2-(nitrophenyl)-2-substituted ethanol, which is characterized by reacting an alkylbenzene. Conventional technology 2-(Nitrophenyl)ethanols are used as polymer compounds, dyes, agricultural chemicals, polymer stabilizers, photosensitive materials,
It is a compound useful as an intermediate for fragrances and pharmaceuticals. However, no industrially advantageous method for its production has been found. For example, there is a method for producing 2-(nitrophenyl)ethanols by reacting 2-nitrotoluenes and paraformaldehyde in the presence of an alkali metal alcoholate catalyst [Acta Chem. Scand., Vol. 21, p. 718 (1967): The same magazine, Vol. 25, p. 1201 (1971)] B.
This method, proposed by Wesselen et al., uses an alkali metal alcoholate, which is a strong base, as a catalyst, and requires special preparation and storage as this catalyst is easily decomposed by moisture in the air. It cannot be said that this is a practically advantageous manufacturing method because of the need for caution. On the other hand, a method of using an alkali metal salt of phenols as a catalyst has been proposed as an improvement method (Japanese Patent Laid-Open No. 52-108941
No.), method using caustic alkali (Japanese Unexamined Patent Publication No. 1983-
122330), DBU (1,8-diazabicyclo(5,
4,0) Undecene-7) Method using quaternary ammonium hydroxide salts (JP-A-52-139035
No.), a method using a complex formed from an alkali metal alcoholate and a crown ether (Japanese Unexamined Patent Publication No. 1983
Similar to the method of B. Wesselen et al., the method used by B. Wesselen et al. uses a base catalyst which is expensive and requires special care in handling. Furthermore, there are not many reports on methods for obtaining substituted benzeneethanols by reacting substituted alkylbenzene derivatives other than 2-nitrotoluenes with paraformaldehyde. For example, DMSO (dimethyl sulfoxide) is added to ethyl 4-methoxyphenyl acetate.
In the presence of sodium ethoxide, paraformaldehyde was reacted to produce ethyl 2-(4-methoxyphenyl)-3-hydroxypropionate.
% yield [Arch.Pharm. (Weinheim,
Ger.) Vol. 305, p. 839 (1972); CA78.42988u],
The phenyl acetate derivative was reacted with paraformaldehyde in DMSO in the presence of an alkali metal alcoholate in the same manner as above to obtain 2-(phenyl)-
There are only a few examples of methods for obtaining 3-hydroxypropionic acid ester derivatives [Czech. These methods also have the same disadvantages as the above-mentioned methods, such as the use of alkali metal alcoholates, which are difficult to handle, as base catalysts, the need to raise the reaction temperature to increase the conversion rate, and the possibility of undesirable side reactions. These methods have the disadvantage that they proceed simultaneously and the yield and selectivity of the target substituted benzene ethanols are low, and these methods cannot be said to be advantageous from an industrial standpoint as a whole. Problems to be Solved by the Invention There is a desire for the development of a method for producing 2-(nitrophenyl)-2-substituted ethanols in good yields without using alcoholate catalysts that are difficult to handle. Means for Solving the Problems The present inventors improved the above-mentioned drawbacks found in the conventional production method and efficiently produced 2-(nitrophenyl)-
The present invention was achieved as a result of extensive research into methods for producing 2-substituted ethanols. That is, general formula (1) [In formula (1), R ₁ is a C _1-4 substituted or unsubstituted alkyl group; cycloalkyl group; aryl group; aralkyl group; halogen atom; cyano group; or COOR
(R represents a C _1-4 alkyl group, aryl group or aralkyl group) group, R ₂ is a hydrogen atom;
Halogen atom; nitro group; hydroxyl group; C _1-4 alkyl group; C _1-4 alkoxy group; cycloalkyl group;
Amino group: represents an aryl group or an aralkyl group, and the nitro group is at the ortho or para position to the CH _{2 R} group, and when R ₂ is at the ortho position to the CH _{2 R} group, it is the same as R ₁ . _R2 may be bonded to form a ring] and paraformaldehyde are electrolytically reduced in the presence of a supporting electrolyte, or paraformaldehyde is electrolytically reduced in the presence of a supporting electrolyte. Electrolytic reduction (electrolytic reaction) is carried out, and then the resulting reduction product is nitro-substituted as represented by the above formula (1).
When alkylbenzenes are reacted (addition reaction), the formula
(2) [In formula (2), R ₁ and R ₂ have the same meanings as above.
represents 1 or 2, and the nitro group is

The method is to produce 2-(nitrophenyl)-2-substituted ethanols represented by the formula: [located at the ortho or para position with respect to the group]. As mentioned above, the conventional method requires various measures to increase the conversion rate and yield, but the method of the present invention is simple and has a high yield.
Moreover, it is surprising that 2-(nitrophenyl)-2-substituted ethanols can be easily obtained at a reaction temperature around room temperature. Specific examples of the nitro-substituted alkylbenzenes represented by formula (1) used in the method of the present invention include 2-nitro-ethylbenzene, 4-nitro-ethylbenzene,
Ethylbenzene, 2-nitroquimene, 4-nitroquiumene, 2-nitropropylbenzene, 4-
Nitropropylbenzene, 2-nitrobutylbenzene, 4-nitrobutylbenzene, 2-nitrohydroxymethylbenzene, 4-nitrohydroxymethylbenzene, 2,4-dinitroethylbenzene, 5-nitrotetralin, 6-nitrotetralin, 4-nitro indane, 5-nitroindane,
2-chloro-4-nitroethylbenzene, 4-hydroxy-2-nitroethylbenzene, 4-cyclohexyl-2-nitroethylbenzene, 4-methoxy-2-nitroethylbenzene, 4-ethyl-3-nitrobiphenyl, 2-nitrocyclohexylmethylbenzene , 4-nitrocyclohexylmethylbenzene, 2-nitrobenzylbenzene,
4-Nitrobenzylbenzene, 1-(2-nitrophenyl)-2-phenylethane, 1-(4-nitrophenyl)-2-phenylethane, 2-nitrobenzyl chloride, 4-nitrobenzyl chloride, 4-nitrobenzyl bromide, 2- Nitrobenzyl bromide, 2,4-dinitrobenzyl chloride, 4-methoxy-2-nitrobenzyl chloride, 4-hydroxy-2-nitrobenzyl cyanide, 4-butoxy-2-nitrobenzyl cyanide, 2-chloro-4- nitrobenzyl cyanide, 4-amino-2-nitrobenzyl cyanide,
2-nitrobenzyl cyanide, 4-nitrobenzyl cyanide, ethyl 2-nitrophenyl acetate, 4
-Methyl nitrophenyl acetate, 4-hydroxy-
Methyl 2-nitrophenyl acetate, phenyl 4-nitrophenyl acetate, benzyl 2-nitrophenyl acetate, butyl 2-hydroxy-4-nitrophenyl acetate, ethyl 4-amino-2-nitrophenyl acetate, ethyl 2-nitro-4-methoxyphenyl acetate, Examples include ethyl 4-chloro-2-nitrophenyl acetate, methyl 4-bromo-2-nitrophenyl acetate, butyl 4-iodo-2-nitrophenyl acetate, and the like. As the supporting electrolyte used in the present invention, salts that are subjected to ordinary electrolytic reactions can be used, but preferred ones are those of the following formula: [In the formula, R ¹ , R ² , R ³ and R ⁴ are the same or different substituted or unsubstituted alkyl groups, and X ^- is

A quaternary ammonium salt represented by [Formula] ClO ₄ ^-halide ion, an anion that pairs with an ammonium ion such as HSO ₃ ^- , CN ^- or BF ₄ ^- to form a quaternary ammonium salt. Some specific examples include the following: Quaternary ammonium salts such as tetramethylammonium paratoluenesulfonate, tetraethylammonium paratoluenesulfonate, and tetrabutylammonium paratoluenesulfonate paratoluenesulfonic acid esters: tetramethylammonium perchlorate, tetraethylammonium perchlorate, tetraperchlorate Perchloric acid quaternary ammonium salts such as butylammonium: Halogenated quaternary ammonium salts such as tetramethylammonium bromide, tetraethylammonium bromide, n-dodecyltrimethylammonium bromide, cetyltrimethylammonium bromide, and tetraethylammonium iodide: tetramethyl Quaternary ammonium salts such as ammonium cyanide, tetraethylammonium cyanide, and tetrabutylammonium cyanide: Quaternary ammonium salts such as tetraethylammonium tetrafluoroborate. Other compounds used as the supporting electrolyte include alkali metal perchlorates such as sodium perchlorate and potassium perchlorate; alkali metal halides such as sodium iodide and potassium iodide. The amount of these supporting electrolytes to be used varies depending on the reaction medium (solvent) and the shape of the reaction tank, but it is usually in the range of 0.1 to 30 times, preferably 0.3 to 10 times, the weight ratio of the nitro-substituted alkylbenzenes. It is. Further, the amount of paraformaldehyde used in the present invention varies depending on the type of substrate (raw material), but is usually in the range of 0.1 to 10 times the mole, preferably 0.5 to 3.0 times the mole. The method of the present invention is carried out in an organic solvent, and as the organic solvent, an aprotic polar solvent or a mixed solvent of an aprotic polar solvent and another solvent can be used. As the aprotic polar solvent, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, hexamethylphosphotriamide, dimethylacetamide, dioxane, dimethoxyethane, acetonitrile, propionitrile, etc. are used. If necessary, a mixed solvent of these and an aliphatic alcohol such as methanol, ethanol, isopropyl alcohol, tertiary butyl alcohol, etc. can also be used. Particularly preferred are dimethylformamide and a mixed solvent containing dimethylformamide as the main solvent. The amount of these solvents to be used is in the range of 1 to 100 times, preferably 3 to 30 times, the weight of the nitro-substituted alkylbenzenes. For the electrolytic reaction of the present invention, common electrodes for electrolysis, ie, electrodes made of materials such as platinum, carbon, nickel, lead, copper, stainless steel, zinc, aluminum, etc., and titanium electrodes surface-treated with platinum, can be used. In the present invention, a single cell or a separate cell with separate anode and cathode chambers is used, but a separate cell is preferred. At this time, the diaphragm that separates the anode and cathode chambers is not particularly limited, but glass filters, unglazed magnetic materials, ion exchange membranes, etc. are used. In addition, the reaction temperature during the electrolytic reaction and its subsequent reaction (addition reaction) is usually 0 to 100°C, preferably 5 to 40°C,
The reaction time is 0.5 to 10 hours, preferably 1 to 5 hours. In the electrolytic method of the present invention, a constant electrolytic method or a constant current method can be adopted. Current density is 0.1-100mA/ ^cm2
Although the amount of electricity applied varies depending on the shape of the reaction tank and the type of substrate used, it is usually within the range of 1 mole of nitro-substituted alkylbenzene.
A current of 0.005-2F, preferably 0.01-1.0F is sufficient.
The concentration of the substrate in the cathode chamber is usually 1 to 50% by weight, preferably 5 to 30% with respect to the solvent used.
is within the range of As described above, the method of the present invention uses an electrolytic reaction to react nitro-substituted alkylbenzenes and paraformaldehyde at around room temperature in the presence of a supporting electrolyte to produce 2-(nitrophenyl)-2-substituted ethanols. or electrolytically reducing paraformaldehyde in the presence of a supporting electrolyte, then adding nitro-substituted-alkylbenzenes to the cathode chamber and reacting, or transferring the catholyte to another container,
By adding and reacting nitro-substituted alkylbenzenes thereto, it is possible to obtain 2-(nitrophenyl)-2-substituted ethanols in high yield without producing by-products. The generated 2-(nitrophenyl)-2-substituted-
Ethanols can be easily separated and purified from the reaction mixture using known methods such as distillation and extraction. Examples The present invention will be explained in more detail by examples. Example 1 Weigh out 303 mg (2.0 mmol) of 2-nitroethylbenzene and 122 mg (4.1 mmol as formaldehyde) of 2-nitroethylbenzene (4.1 mmol as formaldehyde) into the cathode chamber of an anode-cathode chamber separation cell, and add detraethylammonium paratoluenesulfonate (Et) as a supporting electrolyte. _Four
Add 300 mg (1.0 mmol) and 6.0 ml of dimethylformamide (DMF) as a solvent. Meanwhile, add 300 mg of Et ₄ NOTs and 6.0 ml of DMF to the anode chamber.
A thermometer and a platinum electrode (size 1.5 x 1.0 cm ² ) are sufficiently immersed in the solution to be reacted and attached to the positive and negative polarity chambers. Keep the reaction temperature at 20-26℃,
Under the conditions of current density 3.3mA/cm ² and terminal voltage 7 to 9V,
Electrolysis was stopped when an amount of electricity of 0.55 F/mol was applied. Next, the catholyte was poured into a saturated saline solution and the pH was adjusted to 4 with a 5% aqueous hydrochloric acid solution. It was extracted several times with ethyl acetate, and the extract was washed with water, dried over Glauber's salt, and concentrated. Using a silica gel column, the obtained crude product was extracted with benzene and further developed with a mixed solvent of n-hexane-ethyl acetate (5:1), resulting in 2-(2-
345 mg of nitrophenyl)-2-methylethanol
(95.0%) obtained. The conversion rate of this reaction was 100%. 1R and NMR measurement results of 2-(nitrophenyl)-2-methylethanol IR (neat) 3320, 2960, 2920, 1612, 1580, 1525, 1485, 1446, 1356, 1298, 1198, 1055, 1036, 978, 854, 783, 750, 710, 670 cm ^-1 NMR (CDCl ₃ ) δ 1.28 (d, J=6.4Hz, 3H, −CH ₃ ) δ 2.12 (br.s, 1H, −OH) δ 3.21 to 3.80 (m, 3H , -CH-CH ₂ -) δ 7.10 to 7.73 (m, 4H, Ar-H) Example 2 Weigh out 151 mg of paraformaldehyde (5 mmol as formaldehyde) into the cathode chamber of a positive and cathode separation cell, and add it as a supporting electrolyte. Et ₄ NOTs400
mg (1.33 mmol), and add 6 ml of DMF as a solvent. Meanwhile, add 400 mg of Et ₄ NOTs and 6 ml of DMF to the anode chamber. Attach a stirrer, a thermometer, and platinum electrodes (size, 1.5 x 1.0 cm ² ) to both the anode and cathode chambers by fully soaking them in the reaction vessel. The electrolysis was stopped when an amount of electricity of 0.53 F/mol was passed under the conditions that the reaction temperature was maintained at 18 to 25°C, the current density was 3.3 mA/cm ² , and the terminal voltage was 9 to 10 V. Next, 2-nitroethylbenzene is added to the cathode chamber.
Add 318mg (2.1mmol) and reduce the reaction temperature to 20-25℃
The mixture was kept at a constant temperature and stirred for 2 hours. Next, pour the reaction solution in the cathode chamber into saturated saline and adjust the pH to 4.5 with 5% aqueous hydrochloric acid solution.
I made it. It was extracted several times with ethyl acetate, and the extract was washed with water and then dried and concentrated. The obtained crude product was passed through a silica gel column, followed by benzene outflow, and then n-
When developed with a mixed solvent of hexane-ethyl acetate (5:1), 332.6 mg (87.5%) of 2-(2-nitrophenyl)-2-methylethanol was obtained. The conversion rate of this reaction was 100%. The IR and NMR measurement results were the same as those in Example 1. Comparative example 1 2-nitroethylbenzene 303 mg (2.0 mmol),
Paraformaldehyde 120.1 mg (4.0 mmol),
Sodium methoxide 54mg in a mixture of DMF.6ml
(1.0 mmol) was added thereto, and the mixture was stirred at room temperature (16°C) for 1 hour and further at 50°C for 2 hours. The reaction mixture was poured into saturated brine and neutralized with 5% aqueous hydrochloric acid. Extract with ethyl acetate several times, wash the extract thoroughly with water,
It was dried (mirabilite) and concentrated. The obtained crude product was filtered with benzene using a silica gel column, and further n-
When developed with a mixed solvent of hexane-ethyl acetate (5:1), 15 mg (4.1%) of 2-(2-nitrophenyl)-2-methylethanol was obtained. The conversion rate of this reaction was 16.8%. Examples 3 to 9 Table 1 shows the results of reactions conducted in substantially the same manner as in Example 1, but with different types of cathodes.

[Table] Reaction conditions Raw material 2-nitroethylbenzene: 303 mg
(2.0mmol), paraformaldehyde: 122mg
(4.1mmol), supporting electrolyte: Et ₄ NOTs: 300mg×
2, DMF: 6.0 x 2ml, reaction temperature: 20-25℃, current: 5mA, quantity of electricity: 0.55F/mol Examples 10-25 The results were obtained by performing almost the same procedure as in Example 1 but changing the supporting electrolyte. It is shown in Table 2.

[Table] Raw material 2-nitroethylbenzene: 300mg
(2.0 mmol), anode and cathode: platinum electrode (1.5 x 1.0 cm ² ), paraformaldehyde: 122 mg (4.1 mmol),
DMF: 6.0ml x 2, reaction temperature: 20-29℃, current:
5 mA, quantity of electricity: 0.5 to 0.6 F/mol In the table, Me represents methyl, Et represents ethyl, Bu represents butyl, and Ph represents phenyl group. Examples 26 to 34 Table 3 shows the results obtained by performing almost the same operation as in Example 1 but changing the solvent.

[Table] Reaction conditions Raw material 2-nitroethylbenzene: 300mg
(2.0mmol), paraformaldehyde: 120mg
(4 mmol), anode and cathode: platinum electrode (1.5 x 1.0 cm ² ), Et ₄
NOTs (cathode chamber), 1.0 to 1.3 mmol, [ ^* Bu ₄ NClO ₄ (0.9 mmol) instead of Et ₄ NOTs only in the case of THF
was used. ] Reaction temperature: 20-26℃, current: 5mA, amount of electricity:
0.5F/mol Example 35 If the reaction is carried out in the same manner as in Example 1 except that 4-nitroethylbenzene is used instead of 2-nitroethylbenzene as the raw material, 2-nitroethylbenzene is used as the raw material.
(4-nitrophenyl)-2-methylethanol68
mg (18.8%), 2-methyl-2-(4-nitrophenyl)-1,3-propanediol 276 mg (65.4
%)was gotten. The conversion rate of this reaction was 100%. IR and NMR measurement results of 2-(4-nitrophenyl)-2-methylethanol IR (neat) 3340, 2960, 2920, 2853, 1608, 1600, 1515, 1350, 1110, 1055, 1015, 858, 755, 700cm ^{- 1} NMR (CDCl ₃ ) δ1.36 (d, J=6.8Hz, 3H, −CH ₃ ) δ2.60 (br.s, 1H, −OH) δ2.70~3.35 (m, 1H,

[Formula]) δ3.75 (d, 2H, -CH ₂ -) δ7.20-8.20 (m, 4H, Ar-H) 2-methyl-2-(4-nitrophenyl)-1,
IR and NMR measurement results of 3-propanediol IR (CHCl ₃ ) 3380, 2920, 2860, 1663, 1605, 1515, 1352, 1035, 910, 860, 850, 695 cm ^-1 NMR (CDCl ₃ ) δ1.25 (s , 3H, -CH ₃ δ3.03 (br.s, 2H, -OH) δ3.85 (br.s, 4H, -CH ₂ -) δ7.20~8.20 (m, 4H, Ar-H) Examples 37 If the reaction is carried out in the same manner as in Example 2 except that 4-nitroethylbenzene is used instead of 2-nitroethylbenzene as the raw material, 2-nitroethylbenzene is used.
(4-nitrophenyl)-2-methylethanol
210mg (70%), 2-methyl-2-(4-nitrophenyl)-1,3-propanediol 53.5mg
(15.3%) was obtained. The conversion rate of this reaction is 95.7%
It was hot. The IR and NMR measurement results were the same as those of Example 36. Example 38 215 mg (1.2 mmol) of 6-nitrodetraline and paraformaldehyde were added to the cathode chamber of the positive and cathode chamber separation cell.
Weigh out 133 mg (4.4 mmol as formaldehyde) and add 400 mg of Et ₄ NOTs as a supporting electrolyte.
(1.3 mmol) and 6.0 ml of DMF as a solvent.
Meanwhile, add 400 mg of Et ₄ NOTs and 6.0 ml of DMF to the anode chamber. A stirrer, a thermometer, and a platinum electrode (size, 1.5 x 1.0 cm ² ) are fully soaked in the reaction solution and attached to both the anode and cathode chambers. Keep the reaction temperature at 20-25℃,
Under the conditions of current density 3.3mA/cm ² and terminal voltage 5 to 7V.
Electrolysis was stopped when an amount of electricity of 0.34F/mol was applied. Next, the catholyte was poured into a saturated saline solution, and the pH was adjusted to 4.5 with a 5% aqueous hydrochloric acid solution. Extraction was performed with ethyl acetate, and the extract was washed with water, dried, and concentrated. The obtained crude product was purified using a silica gel column, followed by elution with benzene, and further developed with a mixed solvent of n-hexane-ethyl acetate (3/1) to obtain 15 mg (6%) of 1-hydroxymethyl-6-nitrotetralin.
278 mg (83%) of 1,1-di(hydroxymethyl)-6-nitrotetralin was obtained. The conversion rate of this reaction was 95%. IR and NMR measurements of 1-hydroxymethyl-6-nitrotetralin IR (nujol) 3300, 1595, 1520, 1355, 1047, 920, 900, 805, 740 cm ^-1 NMR (CDCl ₃ ) δ1.72-2.05 (m , 4H, −CH ₂ CH ₂ −) δ2.76~2.97 (m, 2H, Ar−CH ₂ −) δ2.50 (br.s, 1H, −OH) δ3.75 (d, 2H, −CH ₂ -) δ2.76~2.97 (m, 1H, -CH-) δ7.16~8.05 (m, 3H, Ar-H) IR, NMR measurement values of 1.1-di(hydroxymethyl)-6-nitrotetralin IR( nujol) 3345, 1585, 1515, 1365, 1100, 1050, 1020, 835, 798, 750, 722cm ^-1 NMR (d ⁶ -acetone) δ1.70-2.10 (m, 4H, -CH ₂ CH ₂ -) δ2 .75~3.00 (m, 2H, Ar-CH ₂ -) δ3.65~4.04 (m, 6H,

[Formula]) δ7.60-8.10 (m, 3H, Ar-H) Example 39 5 instead of 6-nitrotetralin as a raw material
- Using nitrotetralin, the reaction was carried out in the same manner as in Example 38 except for the following conditions: 278 mg of 4-hydroxymethyl-5-nitrotetralin (83
%)was gotten. The conversion rate of this reaction was 94%. IR, NMR measurements of 4-hydroxymethyl-5-nitrotetralin IR (neat) 3320, 2947, 2865, 1600, 1525, 1460, 1360, 1290, 1040, 1020, 850, 805, 790, 770, ^{735 cm -1} NMR (CDCl ₃ ) δ1.72~2.05 (m, 4H, -CH ₂ -CH ₂ -) δ2.26 (br.s, 1H, -OH) δ2.76 - 2.97 (m, 2H, Ar-CH ₂ −) δ3.40 to 3.95 (m, 3H, Ar-CH-CH ₂ -O-) δ7.04 to 7.75 (m, 3H, Ar-H) Example 40 91 mg of paraformaldehyde was placed in the cathode chamber of the anode-cathode separation cell. (30.3 mmol) and 450 mg of tetraethylammonium bromide as the supporting electrolyte.
Add 6ml of DMF. Meanwhile, add 450 mg of tetraethylammonium bromide and 6.0 ml of DMF to the anode chamber. Attach a stirrer, a thermometer, and stainless steel electrodes (1.5 x 1.0 cm) to both the anode and cathode chambers by thoroughly soaking them in the reaction solution. Electrolysis was stopped when an amount of electricity of 0.1 F/mol was passed under the conditions that the reaction temperature was maintained at 20 to 29° C., the current density was 3.3 mA/cm ² ), and the terminal voltage was 9 to 12 V. Next, 422 mg (2.0 mmol) of ethyl 4-nitrophenyl acetate was added to the cathode chamber and the reaction temperature was increased to 20~20 mmol.
The mixture was kept at 29°C and reacted for 1 hour. Pour the reaction solution in the cathode chamber into saturated saline, and adjust the pH of the liquid with 5% hydrochloric acid aqueous solution.
I set it to 4.5. It was extracted several times with ethyl acetate, and the extract was washed with water and then dried and concentrated. The obtained crude product was extracted with benzene using a silica gel column, and further developed with a mixed solvent of n-hexane and ethyl acetate (5/1) to obtain 264.6 mg of 2-ethoxycarbonyl-2-(4-nitrophenyl)ethanol (54.9%). ), 216.3 mg (39.8%) of 2-ethoxycarbonyl-2-(4-nitrophenyl)-1,3-propanediol was obtained. The conversion rate of this reaction was 96.2%. IR and NMR measurements of 2-ethoxycarbonyl-2-(4-nitrophenyl)ethanol IR (neat) 3400, 2970, 1730, 1610, 1600, 1525, 1355, 1178, 1110, 1040, 1020, 860, 745, 700cm ^-1 NMR (CDCl ₃ ) δ1.23 (t, 3H, −CH ₃ ) δ2.68 (br.s, 1H, −OH) δ3.95 to 4.45 (q, 2H, −CH ₂ −) δ3.75 ~4.30 (m, 3H, -CH-CH ₂ -) δ7.35 ~ 8.40 (m, 4H, Ar-H) IR of 2-ethoxycarbonyl-2-(4-nitrophenyl)-1,3-propanediol,
NMR measurement value IR (CHCl ₃ ) 3420, 2980, 2940, 1730, 1605, 1530, 1355, 1305, 1240, 1115, 1100, 1065, 1040, 910, 860, 700 cm ^-1 NMR (CDCl ₃ ) δ1.05~ 1.45 (t, 3H, −CH ₃ ) δ3.00 (br.s, 2H, −OH) δ3.95 to 4.50 (q, 2H, −CH ₂ −) δ4.18 (br.s, 4H, −CH ₂ -O-) δ7.25-8.28 (m, 4H, Ar-H) Examples 41-66 Raw materials, cathode and Table 4 shows the results obtained by changing the supporting electrolyte.

【table】

[Table] Reaction conditions Raw materials: 2 mmol, paraformaldehyde: 90 mg
(1.5mmol), supporting electrolyte: 1.0-1.5mmol×2,
DMF: 6.0ml x 2, positive electrode: platinum electrode (1.0 x 1.5
^cm2 ), reaction temperature: 20~29℃, current: 5mA, quantity of electricity
0.5F/mol Reaction time (Method B): 2 hours, Reaction temperature (Method B): 20 to 29°C In the table, product 2 is a 2-molecule in which one molecule of formaldehyde is added to the raw material nitro-substituted alkylbenzene. (Nitrophenyl)-2-substituted ethanols, and 3 is 2-(nitrophenyl)-2-substituted-1,3-propanediols obtained by adding two molecules of formaldehyde to the raw material nitro-substituted alkylbenzenes. Effects of the Invention 2-(nitrophenyl)-2-substituted-ethanols can be efficiently produced by electrolytic reaction without using alcoholate catalysts that are troublesome to handle.

Claims (1)

[Claims] 1 General formula (1) [In formula (1), R ₁ is a C _1-4 substituted or unsubstituted alkyl group; cycloalkyl group; aryl group; aralkyl group; halogen atom; cyano group; or COOR
(R represents a C _1-4 alkyl group, aryl group or aralkyl group), R ₂ is a hydrogen atom; a halogen atom; a nitro group; a hydroxyl group; a C _1-4 alkyl group; a C _1-4 alkoxy group; cycloalkyl group; amino group; represents an aryl group or an aralkyl group, where the nitro group is at the ortho or para position to the CH ₂ R ₁ group and R ₂ is at the ortho position to the CH ₂ R ₁ group; In some cases, R ₁ and R ₂ may combine to form a ring] ortho- or para-nitro-substituted alkylbenzenes and paraformaldehyde are electrolytically reduced in the presence of a supporting electrolyte, or paraformaldehyde is electrolytically reduced in the presence of a supporting electrolyte, and then the resulting reduction product has the formula
Ortho- or para-nitro-substituted as shown in (1)
Formula (2) characterized by reacting alkylbenzenes [In formula (2), R ₁ and R ₂ have the same meanings as above.
represents 1 or 2, and the nitro group is at the ortho or para position with respect to the [Formula] group.