Method for preparing aldehyde from halogenated hydrocarbon through manganese catalysis

Abstract

The invention discloses a simple method for preparing aldehyde in N, N-dimethylformamide by using halogenated hydrocarbon under the promotion of metal samarium and manganese chloride. The preparation method comprises the following steps: adding halogenated hydrocarbon into N, N-dimethylformamide while stirring, and then sequentially adding metal samarium powder and manganese chloride powder; the reaction system is carried out under an anhydrous condition. Stirring at room temperature until the reaction is complete; and carrying out solvent recovery on the obtained reaction mixed solution. And carrying out column chromatography separation on the crude product, and distilling to remove the solvent to obtain aldehyde, wherein the yield is 60-95%.

Description

Technical Field

[0001] The invention belongs to the field of organic chemical synthesis, and particularly relates to a method for synthesizing aldehyde in one step from halogenated benzene in N,N-dimethylformamide using manganese salt catalysis promoted by metal samarium. Background Art

[0002] Aldehyde compounds have a wide range of applications, whether as solvents, fine chemical products, basic chemical raw materials or organic synthesis reagents. For example, they have extremely important applications in the field of organic synthesis. It is an important method to obtain alcohol structures through catalytic hydrogenation or addition with organometallic reagents. Aldehydes can be reduced to obtain amine compounds through amination [Reference 1. Cantu, DC; Padmaperuma, AB; Nguyen, M.-T.; et al, ACS Catal. 2018, 8 (8), 7645-7658l; Reference 2. Irrgang, T.; Kempe, R., Chem. Rev. 2020, 120 (17), 9583-9674], and aldehyde compounds are also widely used in chiral synthesis [Reference 3. Marcum, JS; Meek, SJ, J. Am. Chem. Soc. 2022, 144 (42), 19231-19237]. In addition, aldehydes can also be used to prepare olefins through decarbonylation reactions [Reference 4. Ainembabazi, D.; Reid, C.; Chen, A.; et al, J. Am. Chem. Soc. 2020, 142 (2), 696-699].

[0003] There are many methods for preparing aldehyde compounds. Among them, the method of preparing aldehydes by oxidation of alcohol compounds, which was discovered very early, is still widely studied and applied [Reference 5. Yan, Q.; Fang, YC; Jia, YX; et al, New J. Chem. 2017, 41 (6), 2372-2377; Reference 6. Wang, L.-Y.; Li, J.; Lv, Y.; et al, J. Organomet. Chem. 2011, 696 (20), 3257-3263]. This method requires equipment with oxidation resistance and usually produces more industrial waste. Relatively speaking, the formylation strategy of olefins is a relatively extensive process for preparing aldehyde compounds in chemical production. This method uses transition metal catalysis to formylate olefins with carbon monoxide and hydrogen to generate aldehydes with an additional carbon atom [for example, document 7. Fleischer, I.; Wu, L.; Profir, I.; et al Chem. Eur. J. 2013, 19 (32), 10589-10594]. This process method has less waste discharge during the reaction, but it requires the use of synthesis gas (CO / H2) at a higher pressure for gas phase reaction, which has higher requirements on equipment, and the chemical selectivity and regioselectivity of the obtained product are also difficult to control. In addition, aldehydes can also be prepared by reduction of carboxylic acid derivatives [document 8. Rysak, V.; Descamps-Mandine, A.; Simon, P.; et al, Catal. Sci. Technol. 2018, 8 (14), 3504-3512], etc. These synthetic methods have different raw materials, methods, and reaction routes with different conditions and environments. They have been widely used in chemical production and organic synthesis.

[0004] Starting from halogenated hydrocarbons, reacting with N,N-disubstituted formamide in the presence of butyl lithium to prepare aldehyde compounds is a relatively unique method. This method directly forms an aldehyde group at the halogen position through lithium-halogen exchange between butyl lithium and halogenated hydrocarbons, and further undergoes a formylation reaction with disubstituted formamide [Reference 9. Gallou, Fabrice; Haenggi, Ruedi; Hirt, Hans; et al, Tetrahedron Lett., 2008, 49 (34), 5024-5027]. Since halogenated hydrocarbons are commonly used basic raw materials for organic synthesis, this method has very good potential value in application. However, since butyl lithium is extremely sensitive to air, moisture, etc., it is an extremely flammable and explosive dangerous reagent, and the reaction process often needs to be carried out at low temperature, generally at -78°C or lower, resulting in stringent requirements for both the reaction operation process and the storage of reagents, and it is difficult to expand the reaction scale. Therefore, this method is currently generally only used in laboratory synthesis. Our previous studies have found that under the catalysis of cuprous iodide, halogenated hydrocarbons as raw materials, N,N-methylformamide (DMF) as solvent, with the help of metal samarium reduction, aldehyde compounds can be obtained in high yield under mild conditions [Document 10. Xiao, S.; Liu, C.; Song, B., et al, Chem. Commun. 2021, 57 (50), 6169-6172]. In contrast, this method has mild operating conditions, easy reagents to use and store, high yield, and good prospects for large-scale preparation. However, this method also has obvious limitations. On the one hand, this method is mainly suitable for the preparation of aromatic aldehydes from halogenated aromatic hydrocarbons, and cannot synthesize fatty aldehydes, which greatly limits the scope of practical application; on the other hand, the reagents used are expensive, cuprous iodide is relatively expensive, and the environment is not friendly enough, which limits large-scale use.

[0005] Samarium is a rare earth element. Since the French chemist Kagan first introduced samarium diiodide into organic synthesis in 1980, samarium reagents have been widely used in organic synthesis. It can promote various types of chemical reactions and functional group transformations, and has been successfully used in the synthesis of various natural products [Reference 11. Szostak, M.; Fazakerley, NJ; Parmar, D.; et al, Chemical Reviews, 2014, 114, 5959-6039]. However, samarium diiodide has some shortcomings in use, such as being very sensitive to air, so it is difficult to store for a long time, and is generally prepared on the spot. On the other hand, samarium diiodide, as a single electron transfer reagent, only uses one electron during use. All of these limit its application in large-scale preparation. In comparison, metallic samarium is more stable in air, easy to operate, relatively cheap, and more electrons can be effectively utilized. Therefore, directly using metallic samarium in organic synthesis has a better prospect. my country has rich rare earth resources, accounting for more than 90% of the world's reserves. The development and utilization of rare earth resources is of great significance.

[0006] The invention discloses a method for preparing aldehyde compounds by using N,N-dimethylformamide (DMF) as solvent and using metal samarium to directly promote the one-step reaction of halogenated hydrocarbons (including halogenated aliphatic hydrocarbons and halogenated aromatic hydrocarbons) and DMF in the presence of manganese chloride. The method has not been reported in domestic and foreign literatures. Summary of the invention

[0007] The object of the present invention is to provide a simple method for preparing aldehydes by using halogenated hydrocarbons with DMF as solvent under the promotion of metal samarium and manganese chloride.

[0008] The technical solution of the present invention is as follows:

[0009] In the presence of manganese salt, samarium metal is used to reduce and couple halogenated hydrocarbons and DMF to aldehydes under mild conditions. The general reaction formula is shown below:

[0010]

[0011] In the formula, X is preferably Br, I; R is preferably alkyl, phenyl.

[0012] The technical scheme of the present invention is as follows: halogenated hydrocarbon is added to N,N-dimethylformamide which has been previously dehydrated and dried under stirring, and then metal samarium powder and manganese chloride powder are added in sequence. The amount of samarium powder is 0.5-5 times the molar ratio of the halogenated hydrocarbon; the amount of manganese chloride is 0.1-1 times the molar ratio of the samarium powder; the amount of N,N-dimethylformamide is 5-50 times the mass of the halogenated hydrocarbon; and the reaction system is carried out under anhydrous conditions.

[0013] The mixture is stirred at room temperature until the reaction is complete. The solvent is recovered from the reaction mixture, and the residue is post-treated and separated by a chromatographic column to obtain a pure aldehyde with a yield of 60-95%.

[0014] The advantages and positive effects of the present invention are as follows: the product obtained by the present invention has a wide range of types and can be used for the synthesis of various aldehyde structures; the synthesis route of the present invention is simple and efficient, and the aldehyde can be obtained by a one-step reaction, with fewer operation steps and no need to separate intermediates, which greatly simplifies the operation requirements; the reaction conditions of the present invention are easy to achieve, and the operation can be directly carried out in the air, avoiding special requirements such as oxygen-free, low temperature, high temperature, light, and biocatalysis; the raw materials of the present invention are simple and easy to obtain, and the halogenated hydrocarbons and manganese salts used are low in cost, are basic chemical products, are easy to obtain, and the manganese salts are relatively friendly to the environment; the metal samarium used in the present invention is a rare earth metal, and my country's rare earth resources rank first in the world, so the effective development and utilization of rare earth metals is of great significance to my country; the aldehyde compounds synthesized by the present invention have a high yield, a simple post-treatment process, and are easy to separate during product post-treatment; the solvent N,N-dimethylformamide used in the present invention can be fully recovered and reused, thereby further reducing the reaction cost. DETAILED DESCRIPTION

[0015] The following synthetic examples are used to further illustrate the present invention but are not intended to limit the present invention.

[0016] Example 1

[0017] Add 0.3g of freshly prepared samarium metal powder and 0.04g of manganese chloride to the reaction vessel in sequence, then add 5mL of anhydrous N,N-dimethylformamide and stir magnetically. Add 0.2mL of bromobenzene. The color of the reaction solution darkens within 1h at 50℃. Continue the reaction for 3h. Add 5mL of dilute hydrochloric acid (2mol·L -1 ) to terminate the reaction, and the reaction mixture was post-treated to obtain a crude product, which was then further purified by a chromatographic column to obtain benzaldehyde with a yield of 94%.

[0018] Colorless oil; 1 H NMR(500MHz,Chloroform-d)δ10.02(s,1H),7.88(m,2H),7.63(m,1H),7.53(m,2H)ppm; 13 C NMR (125MHz, Chloroform-d) δ192.4,136.4,134.4,129.7,129.0ppm.

[0019] Example 2

[0020] According to the method of Example 1, iodobenzene was used instead of bromobenzene to obtain benzaldehyde with a yield of 75%.

[0021] Example 3

[0022] According to the method of Example 1, benzyl bromide was used instead of bromobenzene to obtain phenylacetaldehyde with a yield of 85%.

[0023] Colorless oil; 1 H NMR(500MHz,Chloroform-d)δ9.75(t,J=2.5Hz,1H),7.39-7.22(m,5H),3.69(d,J=2.5Hz,2H)ppm; 13 C NMR (125MHz, Chloroform-d): δ199.5,131.8,129.6,129.0,127.4,50.6ppm.

[0024] Example 4

[0025] According to the method of Example 1, n-bromooctane was used instead of bromobenzene to obtain n-nonanal with a yield of 88%.

[0026] Colorless oil; 1 H NMR(500MHz,Chloroform-d)δ9.76(m,1H),2.42(m,2H),1.63m,2H),1.33-1.24(m,10H),0.88(m,3H)ppm; 13 C NMR (125MHz, Chloroform-d) δ202.52,43.80,31.71,29.23,29.09,29.00,22.53,22.01,13.92ppm.

Claims

1. A simple method for synthesizing aldehydes, characterized in that In the presence of manganese chloride, samarium metal is used to promote the one-step reaction of halogenated hydrocarbons in N,N-dimethylformamide to prepare aldehydes. The preparation process includes the following steps: Under stirring, the halogenated hydrocarbon is mixed evenly in N,N-dimethylformamide which has been previously dehydrated and dried, and then metal samarium powder and manganese chloride powder are added in sequence. Stir at a certain temperature until the reaction is complete. The obtained reaction mixture is subjected to solvent recovery, and the residue is post-treated and separated by a chromatographic column to obtain a pure aldehyde product.

2. A simple method for synthesizing aldehyde according to claim 1, characterized in that The molar ratio of the samarium powder used is 0.5-5 times that of the halogenated hydrocarbon; the molar ratio of the manganese chloride used is 0.1-1 times that of the samarium powder; and the molar ratio of the N,N-dimethylformamide used is 5-50 times that of the halogenated hydrocarbon.

3. A simple method for synthesizing aldehyde according to claim 1, characterized in that The halogenated hydrocarbons used are one or more of halogenated aliphatic hydrocarbons and halogenated aromatic hydrocarbons.

4. A simple method for synthesizing aldehyde according to claim 1, characterized in that The halogenated hydrocarbon used is one or more of chlorinated hydrocarbon, brominated hydrocarbon and iodinated hydrocarbon.

5. A simple method for synthesizing aldehyde according to claim 1, characterized in that The reaction is a one-pot one-step reaction, the reaction solvent can be recovered, and the reaction yield is 60-95%.

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