CN113548964A - Synthetic method of liquid crystal intermediate - Google Patents
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- CN113548964A CN113548964A CN202110899625.6A CN202110899625A CN113548964A CN 113548964 A CN113548964 A CN 113548964A CN 202110899625 A CN202110899625 A CN 202110899625A CN 113548964 A CN113548964 A CN 113548964A
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- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/58—Preparation of carboxylic acid halides
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- C07D307/04—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members
- C07D307/18—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
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Abstract
The invention discloses a synthetic method of a liquid crystal intermediate, which comprises the following operations: preparation of compound B1, hydrolysis of compound B1 to give compound B2; compound B2 and 3, 4-dihydro-2H-pyran are subjected to an ether-forming reaction to protect alcoholic hydroxyl group, and compound B3 is generated; the 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid and a chlorinating agent are subjected to chlorination reaction to prepare a compound A1; carrying out esterification reaction on the compound A1 and hydroquinone to generate a compound A2; carrying out esterification reaction on the compound A2 and the compound B3 under the catalyst to generate a compound A3; and finally, under the action of a catalyst p-toluenesulfonic acid, carrying out deprotection reaction on alcoholic hydroxyl of the compound A3 to generate a compound A4, and obtaining a liquid crystal intermediate. The method adopts the step-by-step reaction to prepare the liquid crystal intermediate, has high reaction selectivity, high yield, environmental friendliness and simple post-treatment, and is suitable for industrial production.
Description
Technical Field
The invention belongs to the field of organic synthesis, and relates to a synthetic method of a liquid crystal intermediate.
Background
The liquid crystal material is a key material of a liquid crystal display, belongs to a solid state and a liquid state, and is an organic substance with certain order. Liquid crystal materials in various phases have been widely used in flat panel displays according to their properties. In recent years, with the development of liquid crystal material research technology and the increasing demand of people for liquid crystal material properties, and in order to meet the higher and higher quality requirements of liquid crystal displays, the development of liquid crystal compounds with high definition of bright points, low viscosity and low threshold has become a major focus of synthetic chemists. Among them, the liquid crystal material having a structural unit of trans-4-dicyclohexyl formate is widely used, and has a wide application in the field of liquid crystal materials due to its high clearing point, low viscosity and wide nematic phase temperature region, and has gradually become an indispensable component of medium-high grade mixed liquid crystal materials.
In the prior art method for producing the liquid crystal intermediate, the cyclohexanol is usually prepared from a cyclohexanol compound through one-step oxidation reaction, expensive and toxic oxidants such as a chromium reagent, a manganese reagent, other transition metal oxides, a high-valence iodine reagent and the like are mostly used in the reaction, the use amount of the oxidants is in an excessive state, so that a large amount of waste pollutants are generated, the reaction selectivity is not high, a large amount of byproducts are generated, the environmental pollution is large, and great pressure is caused on environmental protection.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a synthetic method of a liquid crystal intermediate, the liquid crystal intermediate is prepared by adopting step-by-step reaction, the reaction selectivity is high, the yield is high, the method is environment-friendly, the post-treatment is simple, and the method is suitable for industrial production.
The invention is realized by the following technical scheme:
a synthetic method of a liquid crystal intermediate comprises the following operations:
(1) under the condition of an acid binding agent, carrying out Williams' reaction on methyl paraben and 8-chloro-1-octanol to generate a compound B1: methyl 4- ((8-hydroxyoctyl) oxy) benzoate;
(2) hydrolyzing compound B1 under basic conditions, and after hydrolysis, adjusting the solution to acidic conditions to give compound B2: 4- ((8-hydroxyoctyl) oxy) benzoic acid;
(3) etherifying compound B2 with 3, 4-dihydro-2H-pyran over a catalyst to protect the alcoholic hydroxyl group to produce compound B3: 4- (4- ((8-tetrahydropyranyloxycan) oxy) benzoic acid;
(4) using N, N-dimethylformamide as a catalyst, and carrying out chlorination reaction on 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid and a chlorination reagent to generate a compound A1: 4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carbonyl chloride;
(5) under the condition of an acid binding agent, carrying out esterification reaction on the compound A1 and hydroquinone to generate a compound A2: 4-hydroxyphenyl 4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carboxylic acid phenol ester;
(6) using dicyclohexylcarbodiimide and 4-dimethylaminopyridine as catalysts, and carrying out an esterification reaction on a compound A2 and a compound B3 to generate a compound A3: 4- (4- ((8-tetrahydropyranyloxycan) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-carboxylic acid phenol ester;
(7) and (2) carrying out hydroxyl deprotection reaction on the compound A3 by taking p-toluenesulfonic acid as a catalyst to generate a compound A4: 4- (4- ((8-hydroxy octane) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-phenol formate to obtain a liquid crystal intermediate.
Further, the preparation of the compound B2 in the step (2) comprises the following steps: adding the compound B1 into anhydrous methanol, adding sodium hydroxide aqueous solution, heating to 50-70 ℃, reacting for 4h, cooling to room temperature, adding concentrated hydrochloric acid, adjusting the pH value to 3-4, filtering, and drying to obtain the compound B2.
Further, the preparation of the compound B3 in the step (3) comprises the following steps: adding the compound B2 and 3, 4-dihydro-2H-pyran into a tetrahydrofuran solvent, adding pyridinium p-toluenesulfonate, heating to 30-50 ℃, reacting for 5H, filtering to remove pyridinium p-toluenesulfonate, distilling under reduced pressure to remove tetrahydrofuran, and purifying with acetonitrile to obtain a compound B3.
Further, the preparation of the compound A1 in the step (4) comprises the following steps: adding trans-amyl dicyclohexyl formic acid into dichloromethane, dropwise adding N, N-dimethylformamide to perform catalytic reaction, dropwise adding chlorinated reagent thionyl chloride, heating the mixture to 38 ℃, reacting for 2 hours, cooling the reaction mixture, and evaporating the solvent to obtain a compound A1.
Further, the preparation of the compound A2 in the step (5) comprises the following steps: and dripping the compound A1 into a mixed solution of hydroquinone, pyridine and ethyl acetate, reacting for 2 hours at room temperature, and purifying to obtain a compound A2.
Further, the preparation of the compound A3 in the step (6) comprises the following steps: adding the compound A2, the compound B3 and the catalyst 4-dimethylaminopyridine into dichloromethane, mixing, uniformly stirring, dropwise adding a mixed solution of dicyclohexylcarbodiimide and dichloromethane, reacting at room temperature for 20 hours after dropwise adding is finished, and filtering; methanol was added to the filtrate to precipitate a white solid, which was filtered again to obtain compound a 3.
Further, the preparation of the compound A4 in the step (7) comprises the following steps: mixing the compound A3, dichloromethane and methanol, adding p-toluenesulfonic acid, reacting at room temperature for 20h, distilling under reduced pressure to remove dichloromethane, precipitating white solid, and filtering to obtain a compound A4.
Compared with the prior art, the invention has the following beneficial technical effects:
the invention discloses a synthetic method of a liquid crystal intermediate, which comprises the steps of firstly preparing a compound B3, and in order to improve the reaction yield and the reaction selectivity, protecting alcoholic hydroxyl of a compound B2 by using 3, 4-dihydro-2H-pyran to prepare a compound B3; the method comprises the following steps of carrying out esterification reaction on a compound B3 and a compound A2 to generate a compound A3, and finally carrying out deprotection on alcoholic hydroxyl of the compound A3 to prepare a liquid crystal intermediate.
The method prepares a compound A2 by using a starting material 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid, and prepares a compound A1 by carrying out chlorination reaction on the starting material and a chlorination reagent; then under the acid-binding agent, the compound A1 and hydroquinone are subjected to esterification reaction to prepare a compound A2, the reaction condition in the process is mild, the reaction process is easy to control, and byproducts are less; then under the action of a catalyst dicyclohexylcarbodiimide and 4-dimethylaminopyridine, carrying out an esterification reaction on the compound A2 and the compound B3 to generate a compound A3; and finally, carrying out deprotection reaction on alcoholic hydroxyl of the compound A3 in the presence of a catalyst of p-toluenesulfonic acid to generate a compound A4, namely a liquid crystal intermediate. The method adopts the step-by-step reaction to prepare the liquid crystal intermediate, has high reaction selectivity, high product yield, mild reaction conditions, environmental friendliness and simple post-treatment, and is suitable for industrial production.
Detailed Description
The present invention will now be described in further detail with reference to the following examples, which are intended to be illustrative, but not limiting, of the invention.
The invention provides a synthetic method of a liquid crystal intermediate, which comprises the following operations:
(1) under the condition of an acid binding agent, carrying out Williams' reaction on methyl paraben and 8-chloro-1-octanol to generate a compound B1: methyl 4- ((8-hydroxyoctyl) oxy) benzoate;
(2) hydrolyzing compound B1 under basic conditions, and after hydrolysis, adjusting the solution to acidic conditions to give compound B2: 4- ((8-hydroxyoctyl) oxy) benzoic acid;
(3) etherifying compound B2 with 3, 4-dihydro-2H-pyran over a catalyst to protect the alcoholic hydroxyl group to produce compound B3: 4- (4- ((8-tetrahydropyranyloxycan) oxy) benzoic acid;
(4) using N, N-dimethylformamide as a catalyst, and carrying out chlorination reaction on 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid and a chlorination reagent to generate a compound A1: 4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carbonyl chloride;
(5) under the condition of an acid binding agent, carrying out esterification reaction on the compound A1 and hydroquinone to generate a compound A2: 4-hydroxyphenyl 4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carboxylic acid phenol ester;
(6) using dicyclohexylcarbodiimide and 4-dimethylaminopyridine as catalysts, and carrying out an esterification reaction on a compound A2 and a compound B3 to generate a compound A3: 4- (4- ((8-tetrahydropyranyloxycan) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-carboxylic acid phenol ester;
(7) and (2) carrying out hydroxyl deprotection reaction on the compound A3 by taking p-toluenesulfonic acid as a catalyst to generate a compound A4: 4- (4- ((8-hydroxy octane) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-phenol formate to obtain a liquid crystal intermediate.
Further, the preparation of the compound B2 in the step (2) comprises the following steps: adding the compound B1 into anhydrous methanol, adding sodium hydroxide aqueous solution, heating to 50-70 ℃, reacting for 4h, cooling to room temperature, adding concentrated hydrochloric acid, adjusting the pH value to 3-4, filtering, and drying to obtain the compound B2.
Further, the preparation of the compound B3 in the step (3) comprises the following steps: adding the compound B2 and 3, 4-dihydro-2H-pyran into a tetrahydrofuran solvent, adding pyridinium p-toluenesulfonate, heating to 30-50 ℃, reacting for 5H, filtering to remove pyridinium p-toluenesulfonate, distilling under reduced pressure to remove tetrahydrofuran, and purifying with acetonitrile to obtain a compound B3.
Further, the preparation of the compound A1 in the step (4) comprises the following steps: adding trans-amyl dicyclohexyl formic acid into dichloromethane, dropwise adding N, N-dimethylformamide to perform catalytic reaction, dropwise adding chlorinated reagent thionyl chloride, heating the mixture to 38 ℃, reacting for 2 hours, cooling the reaction mixture, and evaporating the solvent to obtain a compound A1.
Further, the preparation of the compound A2 in the step (5) comprises the following steps: and dripping the compound A1 into a mixed solution of hydroquinone, pyridine and ethyl acetate, reacting for 2 hours at room temperature, and purifying to obtain a compound A2.
Further, the preparation of the compound A3 in the step (6) comprises the following steps: adding the compound A2, the compound B3 and the catalyst 4-dimethylaminopyridine into dichloromethane, mixing, uniformly stirring, dropwise adding a mixed solution of dicyclohexylcarbodiimide and dichloromethane, reacting at room temperature for 20 hours after dropwise adding is completed, and filtering to remove byproducts to obtain a filtrate; methanol was added to the filtrate to precipitate a white solid, which was filtered again to obtain compound a 3.
Further, the preparation of the compound A4 in the step (7) comprises the following steps: mixing the compound A3, dichloromethane and methanol, adding p-toluenesulfonic acid, reacting at room temperature for 20h, distilling under reduced pressure to remove dichloromethane, precipitating white solid, and filtering to obtain a compound A4.
The synthetic route of the liquid crystal intermediate (compound A4) of the invention is as follows:
the synthetic route of the compound B3(4- (4- ((8-tetrahydropyranyloxy octane) oxy) benzoic acid) is as follows:
as can be seen from the synthesis schemes of the compound A4 and the compound B3, the compound B3 and the compound A4 are respectively prepared by step-by-step reaction, and the compound B3 is prepared by carrying out Williams' reaction on methyl-p-hydroxybenzoate and 8-chloro-1-octanol to generate a compound B1; then the compound B1 is hydrolyzed to prepare a compound B2, and the compound B2 and 3, 4-dihydro-2H-pyran are subjected to an ether forming reaction to protect alcoholic hydroxyl to generate a compound B3 for standby. Then preparing a compound A1, and carrying out chlorination reaction on 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid and a chlorination reagent to generate a compound A1; then the compound A1 and hydroquinone are subjected to esterification reaction to generate a compound A2; under the action of a catalyst dicyclohexylcarbodiimide and 4-dimethylaminopyridine, carrying out an esterification reaction on a compound A2 and a compound B3 to generate a compound A3; and finally, carrying out alcohol deprotection reaction on the compound A3 under the action of a catalyst p-toluenesulfonic acid to generate a compound A4, and obtaining a liquid crystal intermediate.
Specifically, the step-by-step reaction steps of the present invention include the following operations:
step (1): preparation of Compound B1 (methyl 4- ((8-hydroxyoctyl) oxy) benzoate)
The reaction mechanism is as follows: in DMF (dimethyl formamide) solvent and under the condition that potassium carbonate is an acid-binding agent, methyl paraben and 8-chloro-1-octanol are subjected to Williams's ether formation reaction to prepare a compound B1.
The specific implementation is as follows: adding 15.2g of methyl paraben into 121ml of N, N-dimethylformamide solution, adding 27.6g of potassium carbonate and 17.5g of 8-chloro-1-octanol, heating to 100 ℃ and 130 ℃ for reaction for 4h, cooling to room temperature, filtering to remove insoluble substances, and evaporating the solvent DMF under reduced pressure to obtain a white waxy solid, namely a crude compound B1.
Step (2): preparation of Compound B2(4- ((8-hydroxyoctyl) oxy) benzoic acid)
The reaction mechanism is as follows: the compound B1 was subjected to alkaline hydrolysis with sodium hydroxide in a methanol-water system, and the solution was made acidic with hydrochloric acid to give compound B2.
The specific implementation is as follows: adding the crude product of the compound B1 prepared in the step (1) into 112ml of anhydrous methanol, then adding a solution prepared from 8g of sodium hydroxide and 112ml of water, heating to 50-70 ℃, reacting for 4 hours, cooling to room temperature, and adding concentrated hydrochloric acid to adjust the pH value of the solution to 3-4; filtering and drying to obtain white solid, namely the compound B2.
And (3): preparation of Compound B3(4- (4- ((8-tetrahydropyranyloxycarbonyl) oxy) benzoic acid)
The reaction mechanism is as follows: in a tetrahydrofuran system, compound B2 takes p-toluenesulfonic acid pyridinium as a catalyst to carry out ether forming reaction with 3, 4-dihydro-2H-pyran to protect alcoholic hydroxyl.
The specific implementation is as follows: adding 21.3g of compound B2 and 10.1g of 3, 4-dihydro-2H-pyran into 128ml of tetrahydrofuran, adding 2g of pyridinium p-toluenesulfonate, heating to 30-50 ℃, reacting for 5H, filtering to remove the pyridinium p-toluenesulfonate, evaporating the tetrahydrofuran under reduced pressure, and purifying by acetonitrile to obtain a white solid, namely compound B3.
And (4): preparation of Compound A1(4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carbonyl chloride)
The reaction mechanism is as follows: 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid is subjected to chlorination reaction in a dichloromethane system by using N, N-dimethylformamide as a catalyst and thionyl chloride as a chlorination reagent.
The specific implementation is as follows: adding 15g (53.4mmol) of trans-amyl dicyclohexyl formic acid into 30ml of dichloromethane, adding 1 drop of N, N-dimethylformamide for catalysis, adding 6.7g (56.3mmol) of thionyl chloride dropwise, heating the mixture to 38 ℃, reacting for 2 hours, cooling the reaction mixture, and evaporating the solvent to obtain a light yellow oily product, namely the compound A1.
And (5): preparation of Compound A2 (4-hydroxyphenyl 4 '-pentyl- [1,1' -di (cyclohexane) ] -4-carboxylic acid phenol ester)
The reaction mechanism is as follows: 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formyl chloride and hydroquinone are subjected to esterification reaction in an ethyl acetate system by taking pyridine as an acid-binding agent.
The specific implementation is as follows: and dripping the compound A1 into a solution containing 11.8g of hydroquinone, 8.5g of pyridine and 200ml of ethyl acetate, reacting for 2 hours at room temperature, and purifying to obtain a white solid, namely the compound A2.
And (6): preparation of Compound A3(4- (4- ((8-tetrahydropyranyloxycarbonyl) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-carboxylic acid phenol ester)
The reaction mechanism is as follows: 4-hydroxyphenyl 4 '-pentyl- [1,1' -di (cyclohexane) ] -4-carboxylic acid phenol ester and 4- (4- ((8-tetrahydropyranyloxycarbonyl) oxy) benzoic acid are subjected to esterification reaction in a dichloromethane system by using dicyclohexylcarbodiimide and 4-dimethylaminopyridine as catalysts.
The specific implementation is as follows: mixing 14.84g of compound A2, 12.7g of compound B3, 0.4g of catalyst 4-dimethylaminopyridine and 101.6ml of dichloromethane, dropwise adding a solution prepared from 8.22g of dicyclohexylcarbodiimide and 25.4ml of dichloromethane while stirring, reacting at room temperature for 20h after dropwise adding, filtering to remove a byproduct DCU, adding 127ml of methanol into the filtrate, precipitating a white solid, and filtering again to obtain the white solid, namely the compound A3.
And (7): preparation of Compound A4(4- (4- ((8-hydroxyoctane) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-carboxylic acid phenol ester)
The reaction mechanism is as follows: compound a3 was subjected to deprotection reaction of alcohol in a mixed solvent system of dichloromethane and methanol using p-toluenesulfonic acid as a catalyst.
The specific implementation is as follows: putting 20g of the compound A3, 80ml of dichloromethane and 80ml of methanol into a reaction vessel, adding 0.5g of p-toluenesulfonic acid, reacting at room temperature for 20h, decompressing and distilling off dichloromethane, separating out a white solid, and filtering to obtain the white solid, namely a liquid crystal intermediate, wherein the purity of the product reaches 96.7%, and the yield of the product is 90.2%.
The compound A4 is prepared by respectively preparing a compound B3 and a compound A2, carrying out esterification reaction on the compound B3 and the compound A2 to prepare a compound A3, and finally carrying out deprotection reaction on the compound A3; the method has the advantages of novel reaction route, easily obtained reaction raw materials, mild reaction conditions, green and environment-friendly reaction process, high reaction selectivity, less by-products, high purity and yield of the finally obtained product, and suitability for industrial production.
According to the technical scheme, the invention provides a synthetic method of a liquid crystal intermediate, firstly, a compound B3 is prepared, in order to improve the reaction yield and the reaction selectivity, the alcoholic hydroxyl of the compound B2 is protected by 3, 4-dihydro-2H-pyran, and the compound B3 is prepared; after the compound B3 and the compound A2 are subjected to esterification reaction to generate a compound A3, and finally, the compound A3 is subjected to deprotection of alcoholic hydroxyl to prepare a liquid crystal intermediate.
In the preparation of a compound B3, readily available initial raw materials, namely methyl paraben and 8-chloro-1-octanol, are adopted, and the compound B1 is generated by carrying out Williams' reaction on the methyl paraben and the 8-chloro-1-octanol to form ether; then after the compound B1 is subjected to alkaline hydrolysis, the solution is adjusted to be acidic by acid to prepare a compound B2, the reaction condition in the process is mild, and the reaction process is easy to control; then, in order to protect the alcoholic hydroxyl group, 3, 4-dihydro-2H-pyran is used to carry out an ether-forming reaction with the compound B2, and a compound B3 is generated. Then preparing a compound A2 by using the starting material 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid, and preparing a compound A1 by carrying out chlorination reaction on the starting material and a chlorination reagent; then under the acid-binding agent, the compound A1 and hydroquinone are subjected to esterification reaction to prepare a compound A2, the reaction condition in the process is mild, the reaction process is easy to control, and byproducts are less; then under the action of a catalyst dicyclohexylcarbodiimide and 4-dimethylaminopyridine, carrying out an esterification reaction on the compound A2 and the compound B3 to generate a compound A3; and finally, carrying out deprotection reaction on alcoholic hydroxyl of the compound A3 in the presence of a catalyst of p-toluenesulfonic acid to generate a compound A4, namely a liquid crystal intermediate. The method adopts the step-by-step reaction to prepare the liquid crystal intermediate, has high reaction selectivity, high product yield and mild reaction conditions, is environment-friendly and is suitable for industrial production.
The embodiments given above are preferable examples for implementing the present invention, and the present invention is not limited to the above-described embodiments. Any non-essential addition and replacement made by the technical characteristics of the technical scheme of the invention by a person skilled in the art belong to the protection scope of the invention.
Claims (7)
1. A synthetic method of a liquid crystal intermediate is characterized by comprising the following operations:
(1) under the condition of an acid binding agent, carrying out Williams' reaction on methyl paraben and 8-chloro-1-octanol to generate a compound B1: methyl 4- ((8-hydroxyoctyl) oxy) benzoate;
(2) hydrolyzing compound B1 under basic conditions, and after hydrolysis, adjusting the solution to acidic conditions to give compound B2: 4- ((8-hydroxyoctyl) oxy) benzoic acid;
(3) etherifying compound B2 with 3, 4-dihydro-2H-pyran over a catalyst to protect the alcoholic hydroxyl group to produce compound B3: 4- (4- ((8-tetrahydropyranyloxycan) oxy) benzoic acid;
(4) using N, N-dimethylformamide as a catalyst, and carrying out chlorination reaction on 4 '-amyl- [1,1' -bis (cyclohexane) ] -4-formic acid and a chlorination reagent to generate a compound A1: 4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carbonyl chloride;
(5) under the condition of an acid binding agent, carrying out esterification reaction on the compound A1 and hydroquinone to generate a compound A2: 4-hydroxyphenyl 4 '-pentyl- [1,1' -bis (cyclohexane) ] -4-carboxylic acid phenol ester;
(6) using dicyclohexylcarbodiimide and 4-dimethylaminopyridine as catalysts, and carrying out an esterification reaction on a compound A2 and a compound B3 to generate a compound A3: 4- (4- ((8-tetrahydropyranyloxycan) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-carboxylic acid phenol ester;
(7) and (2) carrying out hydroxyl deprotection reaction on the compound A3 by taking p-toluenesulfonic acid as a catalyst to generate a compound A4: 4- (4- ((8-hydroxy octane) oxy) benzoyl) oxy) phenyl 4 '-pentyl- [1,1' -di (cyclohexyl) ] -4-phenol formate to obtain a liquid crystal intermediate.
2. The method for synthesizing the liquid crystal intermediate according to claim 1, wherein the preparation of the compound B2 comprises: adding the compound B1 into anhydrous methanol, adding sodium hydroxide aqueous solution, heating to 50-70 ℃, reacting for 4h, cooling to room temperature, adding concentrated hydrochloric acid, adjusting pH to 3-4, filtering, and drying to obtain the compound B2.
3. The method for synthesizing the liquid crystal intermediate according to claim 1, wherein the preparation of the compound B3 comprises: adding the compound B2 and 3, 4-dihydro-2H-pyran into a tetrahydrofuran solvent, adding pyridinium p-toluenesulfonate, heating to 30-50 ℃, reacting for 5H, filtering to remove pyridinium p-toluenesulfonate, distilling under reduced pressure to remove tetrahydrofuran, and purifying with acetonitrile to obtain a compound B3.
4. The method for synthesizing the liquid crystal intermediate according to claim 1, wherein the preparation of the compound A1 comprises: adding trans-amyl dicyclohexyl formic acid into dichloromethane, dropwise adding N, N-dimethylformamide to perform catalytic reaction, dropwise adding chlorinated reagent thionyl chloride, heating the mixture to 38 ℃, reacting for 2 hours, cooling the reaction mixture, and evaporating the solvent to obtain a compound A1.
5. The method for synthesizing the liquid crystal intermediate according to claim 1, wherein the preparation of the compound A2 comprises: and dripping the compound A1 into a mixed solution of hydroquinone, pyridine and ethyl acetate, reacting for 2 hours at room temperature, and purifying to obtain a compound A2.
6. The method for synthesizing the liquid crystal intermediate according to claim 1, wherein the preparation of the compound A3 comprises: adding the compound A2, the compound B3 and the catalyst 4-dimethylaminopyridine into dichloromethane, mixing, uniformly stirring, dropwise adding a mixed solution of dicyclohexylcarbodiimide and dichloromethane, reacting at room temperature for 20 hours after dropwise adding is finished, and filtering; methanol was added to the filtrate to precipitate a white solid, which was filtered again to obtain compound a 3.
7. The method for synthesizing the liquid crystal intermediate according to claim 1, wherein the preparation of the compound A4 comprises: mixing the compound A3, dichloromethane and methanol, adding p-toluenesulfonic acid, reacting at room temperature for 20h, distilling under reduced pressure to remove dichloromethane, precipitating white solid, and filtering to obtain a compound A4.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103265417A (en) * | 2013-05-03 | 2013-08-28 | 西安彩晶光电科技股份有限公司 | Method for synthesizing 4-[2-(trans-4-alkyl cyclohexyl )ethyl]cyclohexanone |
| CN107109227A (en) * | 2014-09-30 | 2017-08-29 | 光学转变公司 | UV absorbers |
| CN111602087A (en) * | 2018-04-19 | 2020-08-28 | Jsr株式会社 | Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal element, polymer and compound |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103265417A (en) * | 2013-05-03 | 2013-08-28 | 西安彩晶光电科技股份有限公司 | Method for synthesizing 4-[2-(trans-4-alkyl cyclohexyl )ethyl]cyclohexanone |
| CN107109227A (en) * | 2014-09-30 | 2017-08-29 | 光学转变公司 | UV absorbers |
| CN111602087A (en) * | 2018-04-19 | 2020-08-28 | Jsr株式会社 | Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal element, polymer and compound |
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