CN114591160A - Method for preparing aryl acetaldehyde from aryl formaldehyde and diaryl ketone - Google Patents

Abstract

The invention discloses a method for preparing aryl acetaldehyde by using aryl formaldehyde or diaryl ketone as raw materials. The aryl acetaldehyde product obtained by the method has one more carbon atom than the original raw material molecule, and the carbon atom is derived from dimethyl sulfoxide. In the reaction process, unsaturated carbon atoms of carbon-oxygen double bonds of raw materials become saturated carbon atoms in the product, carbon atoms from dimethyl sulfoxide are converted into unsaturated carbon atoms of carbon-oxygen double bonds in the product, and the unsaturated carbon atoms are connected to form aryl acetaldehyde. The method for preparing the aryl acetaldehyde has the advantages of wide and easily-obtained raw materials, environmental protection, low price and simple operation, and is beneficial to industrial production.

Description

Method for preparing aryl acetaldehyde from aryl formaldehyde and diaryl ketone

Technical Field

The invention relates to a synthesis method of aryl acetaldehyde, in particular to a synthesis method of aryl acetaldehyde by taking aryl formaldehyde or diaryl ketone as a raw material and carrying out one-pot reaction in dimethyl sulfoxide, belonging to the field of organic synthesis.

Background

Aryl acetaldehyde and its derivatives are a very important class of organic intermediates, widely used in the production and synthesis of fine chemicals and pharmaceutical molecules. For example, 3, 4-dimethoxyphenylacetaldehyde can be used for synthesizing levodopa and other medicaments for treating Parkinson's disease; 4-cyanophenylacetaldehyde is used for synthesizing non-peptide phosphoramidate urokinase inhibitor with antibacterial, anti-inflammatory, anticancer and antirheumatic effects; 4-chloro-2-nitrophenylacetaldehyde and 2-nitrophenylacetaldehyde may be used in the synthesis of indoles and their derivatives. In addition, acetal perfumes prepared from phenylacetaldehyde and derivatives thereof are important perfume blenders; schiff base prepared by reacting phenylacetaldehyde and derivatives thereof with amine can be used for purifying waste water. Since the aryl acetaldehyde and its derivatives have a wide application value and the application range is continuously expanding, the synthesis of aryl acetaldehyde and its derivatives has been receiving close attention from chemists in the past decades, and a large number of synthetic methods have been reported.

Among them, the most widely used method in industrial production is the aromatic alcohol oxidation method. The method takes aryl glycol or beta-aryl ethanol as a reactant to prepare aryl acetaldehyde under the catalytic action of a catalyst. For example, in 2006, the rafie project group reported that a phenylacetaldehyde compound was rapidly synthesized by using β -phenylethyl alcohol as a raw material, potassium periodate (KIO4) as a catalyst and tetraethylammonium bromide as an ionic liquid under the microwave irradiation condition. The method has the advantages of short reaction time, high reaction yield, high chemical selectivity and the like, but the method has higher cost because microwave irradiation is required.

In addition to oxidizing alcohols to produce aryl aldehydes, the direct reduction of aryl acetic acids can also be effective in producing aryl aldehydes. The literature reports a method for preparing aryl acetaldehyde by reducing aryl acetic acid, wherein monobromoborane dimethyl sulfide complex or amino aluminum hydrogenation is used as a catalyst, and dichloromethane or tetrahydrofuran is used as a solvent, so that a phenylacetaldehyde compound can be synthesized with high yield. The method has the characteristics of simplicity and quickness, but the preparation of the catalyst is complicated, so the application of the method is limited.

With the wide application of electrochemistry in organic synthesis, the preparation of aryl acetaldehyde by an electrolytic method is well developed. In 2001, the SunzonRong project group at Beijing university of industry reported a method for preparing phenylacetaldehyde by electrolysis using ethylbenzene as a raw material. The method comprises the steps of firstly, decomposing Mn (II) into Mn (III) in an electrolytic cell with Pb-Sb-As alloy As an electrode, and then, introducing the Mn (III) into a reactor to oxidize ethylbenzene in a sulfuric acid medium into phenylacetaldehyde. The optimal reaction conditions for the reaction are that the sulfuric acid with the concentration of 60 percent, the mass ratio of Mn (III) to ethylbenzene is 1:3-1:5, and the reaction is carried out at the temperature of 60 ℃. The method has the advantages of mild condition, good selectivity, easy separation and the like, but the method has low phenylacetaldehyde yield, large electrolysis energy consumption and high requirement on equipment.

The preparation of aryl acetaldehyde by catalytic isomerization has also been well developed in recent years. In 2003, the Lemaire topic group reported a process for the direct isomerization of ethylene oxide to phenylacetaldehyde. The method comprises reacting 1 mol% of iridium salt as a catalyst (IrCl3.XH2O) in tetrahydrofuran at 50 ℃ for 2 hours. The method has the advantages of simple reaction line, mild reaction conditions and higher selectivity and catalytic activity of the catalyst. However, the method uses the styrene oxide as a raw material, and the reaction cost is high.

In addition, the problem of Shenzhou is that phenylacetylene is used as a raw material, firstly, the phenylacetylene and methanol are synthesized into Z, E configuration mixture of methyl styryl ether under a KOH-DMSO catalytic system, and then the methyl styryl ether is hydrolyzed under an acidic condition to obtain phenylacetaldehyde. The method has simple reaction conditions, does not need a transition metal catalyst, but has poor selectivity and more byproducts, and the reaction needs multi-step reaction, so the reaction process is complicated, and the product yield is low.

In view of the above, these methods are all effective for the synthesis of arylaldehydes. However, the severe reaction conditions, the difficult available reaction raw materials, the expensive catalyst and ligand, the long reaction time and the tedious operation process all hinder the practical application of the methods. These processes are chemically characterized in that one feedstock molecule provides all of the carbon atoms in the aryl acetaldehyde structure.

Disclosure of Invention

Aiming at the defects of difficult obtainment of used raw materials, use of expensive metal catalysts and harsh reaction conditions of the existing aryl acetaldehyde synthesis method, the invention aims to provide the method for synthesizing the aryl acetaldehyde with one saturated carbon atom more than the raw materials by using aryl formaldehyde or diaryl ketone as the raw materials and sulfoxide as a solvent and a reaction reagent under mild reaction conditions in a high yield through one-pot reaction.

In order to realize the technical purpose, the invention provides a simple synthesis method of aryl acetaldehyde, which comprises the steps of taking aryl formaldehyde or diaryl ketone as a raw material, and carrying out one-pot reaction in a DMSO solution system in the presence of KOH and metallic zinc to obtain the aryl acetaldehyde. The aryl acetaldehyde product obtained by the method has one more carbon atom than the original raw material molecule, and the carbon atom is derived from dimethyl sulfoxide. In the reaction process, unsaturated carbon atoms of carbon-oxygen double bonds of the raw materials become saturated carbon atoms in the product, carbon atoms from dimethyl sulfoxide are converted into unsaturated carbon atoms of carbon-oxygen double bonds in the product, and the unsaturated carbon atoms are connected to form aryl acetaldehyde.

The aryl carboxaldehyde or diaryl ketone has the structure of formula 1:

the aryl acetaldehyde has the structure of formula 2:

wherein the content of the first and second substances,

in the formula 1R₁And R₂Is hydrogen, phenyl, naphthalene, thiophene, quinoline or substituted derivatives thereof, except that R₁And R₂Cannot be simultaneously hydrogen; r₁And R₂When one of (a) is hydrogen, formula 1 is an arylcarboxaldehyde; r₁And R₂And when the aryl is simultaneously used, the formula 1 is diaryl ketone. R₁And R₂When the aryl is used, the substituent on the aryl can be one or more of hydrogen, methyl, ethyl, propyl, butyl, isobutyl, isopropyl, tert-butyl, phenyl, cyclohexylmethyl, chlorine and bromine, and the substituent can be positioned at different positions in the aryl ring;

it was found experimentally that the reaction required a reaction under an inert gas atmosphere, such as argon. The base is necessary and the addition of the metal or metal salt can significantly increase the reaction yield of the desired product.

In a preferred scheme, the metal and the metal salt are metal Zn and ZnCl₂、ZnBr₂、Zn(OAc)₂Metal Cu, CuCl, CuBr, CuI, CuCl₂、CuBr₂、CuI₂Metal Fe, FeCl₂、FeBr₂、FeI₂Metallic Zn is preferred.

In a preferred embodiment, the base comprises at least one inorganic or organic base, for example, sodium hydroxide, potassium carbonate, sodium tert-butoxide, potassium tert-butoxide, preferably potassium hydroxide.

In a preferred scheme, the molar ratio of the raw materials of the aryl formaldehyde and the metal zinc to the alkali is 1:1: 4.

The reaction temperature and reaction time have a significant influence on the occurrence of the reaction and the formation of the product. The reaction can hardly be carried out at a temperature lower than 25 ℃ within 2 hours; when the reaction temperature reaches 80 ℃, the highest yield can be achieved after 2 hours of reaction, and the yield of the reaction product is not increased any more when the temperature is increased or the reaction time is prolonged.

In a preferred embodiment, the reaction conditions are as follows: reacting for 0.5-3 hours at the temperature of 25-100 ℃ under the atmosphere of argon. In a more preferred embodiment, the reaction conditions are as follows: the reaction was carried out at 80 ℃ for 2 hours under an air atmosphere.

In the synthesis process of the aryl acetaldehyde, dimethyl sulfoxide is used as a solvent and a reaction substrate at the same time, and a large amount of dimethyl sulfoxide can be used for excessive reaction.

In the preferred scheme, after the reaction is finished, a product is separated and purified by adopting a column chromatography; the eluent adopted by the column chromatography is a mixed solvent of petroleum ether and ethyl acetate, wherein the volume ratio of the petroleum ether to the ethyl acetate is (20-40): 1.

The method for synthesizing the aryl acetaldehyde provided by the invention has the following reaction equation:

the aryl acetaldehyde product of the reaction is added with one carbon atom compared with the original aryl formaldehyde or diaryl ketone molecule, and the carbon atom is derived from dimethyl sulfoxide. In the reaction process, unsaturated carbon atoms of carbon-oxygen double bonds of raw materials become saturated carbon atoms in the product, carbon atoms from dimethyl sulfoxide are converted into unsaturated carbon atoms of carbon-oxygen double bonds in the product, and the unsaturated carbon atoms are connected to form aryl acetaldehyde. The principle of this reaction can be illustrated by the reaction of benzaldehyde with DMSO to form phenylacetaldehyde: first, benzaldehyde and DMSO undergo an Aldol condensation reaction (Aldol reaction) under the action of KOH to produce intermediate a. Then, under the catalysis of zinc, the intermediate A forms an intermediate B in the argon atmosphere, and then the intermediate B is combined with hydroxide ions to form an intermediate C, and the intermediate C is subjected to tautomerization due to instability of enol to generate final product phenylacetaldehyde. The stable intermediate A in the above process can be detected in the reaction system, and the product phenylacetaldehyde can be obtained by using the intermediate A as a starting material. Structural analysis of a reaction product of deuterated DMSO and o-methoxybenzaldehyde confirms that the aldehyde carbon atom of the o-methoxybenzaldehyde product comes from DMSO.

Experiments show that if the aliphatic aldehyde is used for replacing aryl formaldehyde or the aliphatic ketone is used for replacing aryl ketone, the product with the corresponding structure cannot be obtained; the aldehyde ketone containing alpha-methyl hydrogen can generate self Aldol reaction under the reaction condition, and the target product can not be obtained.

Compared with the existing synthesis method and technology, the invention has the following advantages and effects:

1) the invention realizes the reaction of synthesizing aryl acetaldehyde by using aryl formaldehyde or diaryl ketone as raw materials for the first time, and the product aldehyde increases one carbon atom compared with the raw materials of aldehyde ketone compounds, and the increased carbon atom comes from DMSO;

2) the invention adopts simple and common aryl aldehyde ketone and DMSO as raw materials, has wide raw material source and low cost, and meets the requirement of industrial production;

3) the reaction temperature in the reaction process is moderate, the product yield is high, and the method is suitable for industrial production;

4) in the reaction process, toxic raw materials, solvents and additives are not used, harsh reaction conditions are not needed, and the solvents are reactants at the same time, so that the green and environment-friendly requirements are met;

5) the synthesis process of the invention adopts a one-pot reaction, and has the advantages of few reaction steps and simple operation.

The implementation scheme is as follows:

the present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto, and may be performed with reference to conventional techniques for process parameters not specifically mentioned.

All reactions were performed in Schlenk tubes unless otherwise noted.

All reaction starting solvents were obtained from commercial sources and used without further purification.

The product is separated by a silica gel chromatographic column and silica gel (the granularity is 300-400 meshes).

1H NMR (400MHz) and 13C NMR (100MHz) measurements were carried out using a Bruker ADVANCE III spectrometer with CDCl₃Chemical shifts are in parts per million (ppm) based on TMS as internal standard and 0.0ppm based on tetramethylsilane as reference shift. The following abbreviations (or combinations thereof) are used to explain the multiplicity: s is singlet, d is doublet, t is triplet, q is quartet, m is multiplet, br is broad. Coupling constant J is in Hertz (Hz). Chemical shifts are expressed in ppm, with the center line for the triplet state referenced to deuterated chloroform at 77.0ppm or the center line for the heptad state referenced to deuterated DMSO at 39.52 ppm.

1. Reaction condition optimization:

based on the reaction yield of preparing phenylacetaldehyde by reacting benzaldehyde serving as a raw material with DMSO (dimethyl sulfoxide), the types and the amounts of alkali used in the reaction, the types and the amounts of catalysts, the reaction time, the reaction temperature and the like are screened, and an optimal condition for synthesizing the aryl acetaldehyde compound is expected.

1.1 screening of the base type in the reaction

First, we added different bases to the system to investigate the effect of base type on the reaction. The results of the experiment are shown in table 1.1. From the experimental results, it is known that the base is crucial to the reaction, and when no base is added in the reaction, the target product is not detected, and the reaction cannot proceed. When the alkali is KOH, the yield of the target product can reach 75 percent. When the alkali is NaOH,^tBuOK and^tBuONa, the reaction can also occur, but the yield is lower at 12-31%. When the base is K₂CO₃、Na₂CO₃、Li₂CO₃、NaHCO₃And KHCO₃When the reaction is carried out, the reaction hardly occurs. Therefore, we consider KOH as the optimal base for this reaction.

TABLE 1.1 screening of different bases^a

1.2 screening of the amount of base used in the reaction

After confirming that KOH is the optimal alkali, we also carried out systematic screening on the amount of alkali, and the reaction results under different amounts of alkali are shown in Table 1.2. As can be seen from the comparison of the data in the table, the amount of the base has a large influence on the yield of the target product, and when the amount of the base is between 0.25 and 2.0mmol, the yield of the target product is gradually improved along with the increase of the amount of KOH. When the amount of KOH was 2.0mmol, the reaction was most effective and the yield of the objective product was 75%, and on the basis of this, the amount of the base was increased, and the yield of the objective product decreased rather as the amount of KOH was increased, so that 2.0mmol of KOH was the optimum amount for the reaction.

TABLE 1.2 screening of KOH levels^a

1.3 screening of catalyst in the reaction

Based on the determination of the optimal alkali and the dosage, the catalyst types are optimized, and the screening results are shown in the following table 1.3. As can be seen from the table, in the absence of a catalyst, the target product was not substantially produced. When the catalyst is simple substance zinc, the yield of the target product can reach 75%. Other types of zinc salt catalysts such as zinc chloride, zinc bromide, zinc acetate can also catalyze the reaction, but the catalytic effect is not significant resulting in lower yields of the target product. In addition, when other metal and metal salt catalysts such as elementary copper, cuprous chloride, cuprous bromide, cuprous iodide, cupric chloride, cupric bromide, cupric iodide, iron elementary substance, ferrous chloride, ferrous bromide and ferrous iodide are adopted, the yield of the target product is below 57%. Thus, elemental zinc is the optimal additive for this reaction.

TABLE 1.3 screening of catalyst types^a

1.4 screening of the amount of catalyst used in the reaction

Subsequently, we performed systematic optimization on the amount of the catalyst by using the simple substance of zinc as the optimal catalyst, and the reaction results at different catalyst amounts are shown in table 1.4. As can be seen from the data in the table, when the dosage of the catalyst is between 0 and 30mg, the reaction effect is better and better along with the increase of the addition of the zinc simple substance, and the yield of the target product is gradually increased. When the amount of the catalyst to be added is 30mg (0.5mmol), the yield is 75% at the highest, and on the basis of this, the amount of the catalyst to be added is further increased, which hardly affects the yield of the objective product, so that 30mg (0.5mmol) of zinc powder is the optimum amount for the reaction.

TABLE 1.4 screening of catalyst amounts^a

1.5 screening of reaction temperature in the reaction

In organic synthetic chemistry, reaction temperature has a large influence on reaction yield, and the reaction temperature is screened on the basis of determining the optimal catalyst and the dosage thereof, and the result is shown in table 1.5. When the reaction was at normal temperature, the formation of the objective product was not detected, indicating that the reaction could not proceed at normal temperature. When the reaction temperature is 30 ℃, 7 percent of target products can be detected, when the reaction temperature is increased from 30 ℃ to 80 ℃, the reaction effect is better and better, and when the reaction temperature is 80 ℃, the reaction yield reaches 75 percent at most. As the reaction temperature continues to rise, the yield of the desired product decreases. Therefore, we chose 80 ℃ as the optimal reaction temperature for the reaction.

TABLE 1.5 screening of reaction temperatures^a

1.6 optimization of reaction time

Finally, after determining other reaction conditions, we screened the reaction time and the results are shown in table 1.6. The experimental results show that when the reaction time is half an hour, the yield of the target product can be detected to be 37%. When the reaction time is increased from 0.5 hour to 2 hours, the yield of the target product is increased from 37% to 75% of the maximum, and the reaction time is further increased to 3 hours, the yield of the target product is not changed, so that the optimal reaction time is 2 hours.

TABLE 1.6 Effect of reaction time on the reaction^a

In summary, the optimal conditions for the reaction are finally determined by screening factors such as the type and amount of the base, the type and amount of the catalyst, the reaction temperature, the reaction time and the like. The optimal reaction conditions are as follows: benzaldehyde (0.5mmol), KOH (1.5mmol), Zn (0.5mmol) and dimethyl sulfoxide (2.5 mL) were reacted at 80 ℃ under an argon atmosphere for 2 hours.

2. The implementation process comprises the following steps:

2.5mL of dimethyl sulfoxide (DMSO) was added to a 25mL pressure resistant tube, followed by sequentially adding potassium hydroxide (2.0mmol, 4.0equiv), zinc powder (30mg), aromatic aldehyde or diaryl ketone (0.5mmol), and the reaction mixture was reacted in a magnetic stirred oil bath at 80 ℃ for 2 hours. After the reaction is finished, cooling to room temperature, adding 10mL of ethyl acetate for dilution, then transferring to a separating funnel, adding 10mL of saturated saline solution, extracting the reaction solution, taking the upper organic phase, repeating for 3 times, then drying with anhydrous sodium sulfate, evaporating the solvent under reduced pressure, performing column chromatography separation on the crude product by using 300-400-mesh silica gel, performing separation and purification by using PE (petroleum ether)/EA (ethyl acetate) as an eluent to obtain a product, and calculating the yield.

3. The implementation effect is as follows:

the products obtained by the implementation of the aryl formaldehyde or diaryl ketone and the yields are as follows:

4. hydrogen and carbon spectra data for partial products:

2-phenylacetaldehyde(1)

(m,2H),3.67(d,J＝1.6Hz,2H).¹³C NMR(101MHz,CDCl₃)δ199.35,131.76, 129.51,128.88,127.29,50.43.

2-(o-tolyl)acetaldehyde(2)

1.8Hz,2H),2.29(s,3H).¹³C NMR(101MHz,CDCl₃)δ199.15, 137.07,130.55,130.53,130.43,127.69,126.40,48.65,19.62.

2-(m-tolyl)acetaldehyde(3)

1.9Hz,2H),2.36(s,3H).¹³C NMR(101MHz,CDCl₃)δ199.52,138.70,131.67, 130.33,128.86,128.12,126.59,50.50,21.29.

2-(p-tolyl)acetaldehyde(4)

6.6Hz,2H),7.15–7.09(m,2H),3.66(d,J＝1.9Hz,2H),2.37 (s,3H).¹³C NMR(101MHz,CDCl₃)δ199.58,137.01,129.62,129.42,128.63,50.10, 20.99.

2-mesitylacetaldehyde(5)

136.94,129.10,126.17,44.70,20.84,20.32.

1-(4-ethylphenyl)acetaldehyde(6)

7.13(m,4H),3.66(d,J＝1.8Hz,2H),2.66(dd,J＝15.0,7.5 Hz,2H),1.25(t,J＝7.6Hz,3H).¹³C NMR(101MHz,CDCl₃)δ199.67,143.43, 129.52,128.90,128.47,50.16,28.44,15.48.

2-([1,1'-biphenyl]-4-yl)acetaldehyde(7)

J＝7.9Hz,2H),3.74(s,2H).¹³C NMR(101MHz,CDCl₃)δ 199.26,140.56,140.42,130.77,130.02,128.79,127.71,127.40,127.04,50.20.

2-(2-methoxyphenyl)acetaldehyde(8)

(dd,J＝7.4,1.3Hz,1H),6.99–6.89(m,2H),3.82(s,3H),3.65(d,J ＝2.1Hz,2H).¹³C NMR(101MHz,CDCl₃)δ200.10,157.55,131.16,128.87,121.17, 120.72,110.42,55.27,45.33.

2-(3-methoxyphenyl)acetaldehyde(9)

6.94–6.66(m,3H),3.79(s,3H),3.63(s,2H).¹³C NMR(101MHz,CDCl₃)δ199.15, 159.91,133.17,129.85,121.73,115.13,112.67,55.02,50.36.

2-(3-methoxyphenyl)acetaldehyde(10)

6.92(d,J＝8.3Hz,2H),3.80(s,3H),3.62(s,2H).¹³C NMR (101MHz,CDCl₃)δ199.41,158.76,130.47,123.58,114.23,55.03,49.44.

2-(3,4-dimethoxyphenyl)acetaldehyde(11)

6.71(d,J＝8.1Hz,1H),6.67(s,1H),3.81(s,7H),3.56(s,2H). ¹³C NMR(101MHz,CDCl₃)δ199.14,149.03,148.11,123.92,121.55,112.40,111.38, 55.60,55.57,49.77.

2-(2,4,6-trimethoxyphenyl)acetaldehyde(12)

(101MHz,CDCl₃)δ201.32,160.71,159.12,101.77,90.45,55.64,55.33,37.83.

2-(2-fluorophenyl)acetaldehyde(13)

¹³C NMR(101MHz,CDCl₃)δ197.97,161.16(d,J＝246.2Hz), 131.63(d,J＝4.3Hz),129.43(d,J＝8.0Hz),124.45(d,J＝3.7Hz),119.44(d,J＝ 16.3Hz),115.55(d,J＝21.6Hz),43.92.

(2-chlorophenyl)acetaldehyde(14)

3H),3.87(s,2H).¹³C NMR(101MHz,CDCl₃)δ198.21,134.53, 131.69,130.70,129.68,129.06,127.19,48.20.

2-(3-chlorophenyl)acetaldehyde(15)

(m,1H),7.10(d,J＝5.0Hz,1H),3.68(s,2H).¹³C NMR(101MHz,CDCl₃)δ198.37, 134.77,133.73,130.16,129.71,127.76,127.65,49.97.

2-(4-chlorophenyl)acetaldehyde(16)

7.07(m,2H),3.68(s,2H).¹³C NMR(101MHz,CDCl₃)δ198.60, 130.90,130.23,129.08,128.25,49.73.

2-(3-bromophenyl)acetaldehyde(17)

(s,1H),7.28–7.21(m,1H),7.14(q,J＝6.3Hz,1H),3.67(s,2H).¹³C NMR(101 MHz,CDCl₃)δ198.35,134.01,132.60,130.57,130.43,128.22,122.94,49.91.

2-(4-bromophenyl)acetaldehyde(18)

–7.01(m,2H),3.67(d,J＝2.1Hz,2H).¹³C NMR(101MHz,)δ 198.51,132.08,131.28,130.75,121.53,49.85.

2-(naphthalen-1-yl)acetaldehyde(19)

J＝1.9Hz,2H).¹³C NMR(101MHz,CDCl₃)δ199.44,133.84,132.19,128.81,128.36, 128.30,126.60,125.97,125.54,123.45,104.20,48.20.

2-(naphthalen-2-yl)acetaldehyde(20)

(m,3H),7.70(s,1H),7.54–7.46(m,2H),7.37–7.30(m,1H),3.85(d,J＝2.0Hz, 2H).¹³C NMR(101MHz,CDCl₃)δ199.29,133.60,132.55,129.27,128.73,128.50, 127.72,127.58,127.40,126.41,126.04,50.68.

2-(thiophen-2-yl)acetaldehyde(21)

(m,1H),6.96(d,J＝2.8Hz,1H),3.90(s,2H).¹³C NMR(101MHz,CDCl₃)δ197.48, 132.72,127.45,127.20,125.51,43.95.

2,2-diphenylacetaldehyde(22)

127.59,64.08.

2,2-di-p-tolylacetaldehyde(23)

2,2-bis(4-methoxyphenyl)acetaldehyde(24)

2-(4-chlorophenyl)-2-phenylacetaldehyde(25)

130.20,129.15,129.08,127.84,63.35.

2-(4-chlorophenyl)-2-phenylacetaldehyde(26)

Claims (6)

1. a method for preparing aryl acetaldehyde by using aryl formaldehyde or diaryl ketone as raw materials is characterized in that: in the presence of KOH and metallic zinc, an arylformaldehyde or a diaryl ketone reacts in dimethyl sulfoxide to form an aryl acetaldehyde:

the aryl carboxaldehyde or diaryl ketone has the structure of formula 1:

the aryl acetaldehyde has the structure of formula 2:

wherein the content of the first and second substances,

in the formula 1R₁And R₂Is hydrogen, phenyl, naphthalene, thiophene, quinoline or substituted derivatives thereof, except that R₁And R₂Cannot be simultaneously hydrogen; r₁And R₂When one of (A) is hydrogen, formula 1 is arylcarboxaldehyde, R₁And R₂And when the aryl is simultaneously used, the formula 1 is diaryl ketone. R₁And R₂When the aryl is used, the substituent on the aryl can be one or more of hydrogen, methyl, ethyl, propyl, butyl, isobutyl, isopropyl, tert-butyl, phenyl, cyclohexylmethyl, chlorine and bromine, and the substituent can be positioned at different positions in the aryl ring.

2. The process of claim 1 for preparing an aryl acetaldehyde starting from an aryl formaldehyde or a diaryl ketone, wherein: the base is selected from sodium hydroxide, potassium carbonate, sodium tert-butoxide, preferably potassium hydroxide.

3. The process of claim 1 for preparing an aryl acetaldehyde starting from an aryl formaldehyde or a diaryl ketone, wherein: the metal and metal salt are metalsZn、ZnCl₂、ZnBr₂、Zn(OAc)₂Metal Cu, CuCl, CuBr, CuI, CuCl₂、CuBr₂、CuI₂Metal Fe, FeCl₂、FeBr₂、FeI₂Metallic Zn is preferred.

4. The process of claim 1 for preparing an aryl acetaldehyde starting from an aryl formaldehyde or a diaryl ketone, wherein: the reaction temperature is from 25 to 100 deg.C, preferably 80 deg.C.

5. The process of claim 1, wherein the aryl aldehyde is prepared from an aryl formaldehyde or a diaryl ketone as a starting material, and wherein: the reaction time is 0.5 to 3 hours, preferably 2 hours.

6. The process of claim 1 for preparing an aryl acetaldehyde starting from an aryl formaldehyde or a diaryl ketone, wherein: dimethyl sulfoxide serves as a solvent and a reaction reagent.