Preparation method of aromatic ring benzil compound

Abstract

The invention belongs to the technical field of organic synthesis, and particularly discloses a preparation method of an aromatic ring benzil compound, which comprises the following steps: sequentially adding an aromatic ring acyloin compound, hydrated iron oxide (III), inorganic alkali, ethanol and water into a reactor, stirring and reacting for 20-40 minutes in air or oxygen, extracting and separating after the reaction is completed to obtain an organic phase, and purifying the organic phase to obtain the aromatic ring benzil compound. And drying and concentrating an organic phase to obtain a finished product aromatic ring benzil. According to the method, an acyloin compound is used as a raw material, hydrated iron oxide (III) is used as an oxidation additive, and the aromatic ring benzil compound is rapidly synthesized; the synthesis method disclosed by the invention is green and environment-friendly, simple in reaction operation, free of additional separation and purification steps of products, high in reaction speed, obviously improved in reaction yield, low in environmental pollution, capable of effectively reducing the reaction cost and easy to popularize and use, and air is used as an oxidizing agent and alcohol is used as a solvent.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, relates to the synthesis of acyloyl compounds, and specifically relates to a method for preparing aromatic acyloyl compounds by oxidizing acyloin compounds. Background Art

[0002] Isopropylamine compounds are an important class of organic synthesis intermediates, especially aromatic isopropylamine compounds, which have always been a hot topic of research due to their good reactivity and important application value.

[0003] Take benzil as an example:

[0004]

[0005] Benzil can be used as a starting material to synthesize drugs or pharmaceutical intermediates such as phenytoin, fosphenytoin, benzilic acid, etc. The commonly used synthesis method is: using benzoin as a raw material to synthesize benzil through an oxidation reaction, and a metal oxidant is usually added during the reaction.

[0006] The oxidants reported in the literature mainly include nitric acid, Zn(NO3) / SiO2, H2O2, Fe 3+ Among them, the most studied is Fe 3+ However, due to Fe 3+ The properties of salt such as easy to absorb moisture, difficult to preserve, and easy to form colloids with water have greatly limited the application prospects of this type of catalyst.

[0007] With the introduction of the concept of green chemistry, researchers are committed to exploring simple, efficient, green and environmentally friendly oxidation technologies and looking for new and efficient catalysts that are in line with the development direction of green chemistry and provide a green and effective way for the oxidation of acyloin compounds to prepare acylic compounds. Summary of the invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a preparation method of an aromatic ring allyl compound. The present invention uses an acyloin compound as a raw material and hydrated iron (III) oxide (CAS No. 20344-49-4) as an oxidizing additive to quickly synthesize the aromatic ring allyl compound. The synthesis method of the present invention is green and environmentally friendly, has simple reaction operation, does not require additional separation and purification steps for the product, has a fast reaction speed, significantly improves the reaction yield, uses air as an oxidant, uses alcohol as a solvent, has low environmental pollution, can effectively reduce the reaction cost, and is easy to promote and use.

[0009] The present invention is achieved through the following technical solutions:

[0010] A method for preparing an aromatic ring acyl compound comprises the following steps:

[0011] Add aromatic acyloin compound, hydrated iron (III) oxide, inorganic base, ethanol and water into the reactor in sequence, stir and react in air or oxygen for 20 to 40 minutes, extract and separate the organic phase after the reaction is complete, and dry and concentrate the organic phase to obtain the finished aromatic acyloin.

[0012] A further improvement of the present invention is:

[0013] The aromatic ring acyloin compound is benzoin or furanoin.

[0014] Furthermore, the inorganic base is sodium hydroxide or potassium hydroxide or a mixture of the two.

[0015] Furthermore, the molar ratio of the aromatic cyclopentane compound, hydrated iron (III) oxide and inorganic base is 1:1-4:1.5-3.

[0016] Furthermore, the volume ratio of the ethanol to water is 2 to 5:1.

[0017] Furthermore, when feeding, 1 to 3 mL of ethanol is added for every 1 mmol of the aromatic cyclopentyl compound.

[0018] Furthermore, the stirring reaction temperature is 0-130°C.

[0019] Preferably, the stirring reaction temperature is 0-35°C.

[0020] Furthermore, the extraction is performed using saturated saline and ethyl acetate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The synthesis method of the present invention is green and environmentally friendly, has simple reaction operation, does not require additional separation and purification steps for the product, has a fast reaction speed, and significantly improves the reaction yield. Air is used as an oxidant and alcohol is used as a solvent, so the amount of solvent is small, which is more green and environmentally friendly, has low environmental pollution, can effectively reduce the reaction cost, and is easy to promote and use. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with specific embodiments.

[0024] Example 1: Preparation of benzil

[0025]

[0026] Add 424 mg of benzoin, 356 mg of hydrated iron (III) oxide, 160 mg of sodium hydroxide, 3.75 mL of ethanol, and 1.25 mL of water to the reaction bottle and react at room temperature for 60 min under stirring. After the reaction is completed, add 20 mL of saturated salt water and 50 mL of ethyl acetate. Mix well and pour into a separatory funnel, collect the organic phase, dry it over anhydrous sodium sulfate, and concentrate to obtain 343 mg of benzil with a yield of 81.7%. 90–93℃.

[0027] 1 H NMR (400MHz DMSO-d6): δ7.93(d,J=8.00Hz,4H),7.78(t,J=8.00,2H),7.61(t,J=8.00Hz,4H)ppm.

[0028] 13 C NMR (100MHz DMSO-d6): δ195.2,135.9,132.8,130.0129.9ppm.

[0029] Example 2: Preparation of 1,2-difuranylethanedione

[0030]

[0031] In the reaction flask, add 384 mg of furanoin, 356 mg of hydrated iron (III) oxide, 160 mg of sodium hydroxide, 3.75 mL of ethanol, and 1.25 mL of water, and react at room temperature for 30 minutes under stirring. After the reaction is completed, add 20 mL of saturated salt water and 50 mL of ethyl acetate. After mixing evenly, pour into a separatory funnel, collect the organic phase, dry it over anhydrous sodium sulfate, and concentrate to obtain the product: 254 mg of 1,2-difuranylethanedione, yield 66%.

[0032] 1 H NMR (400MHz DMSO-d6): δ8.24 (s, 2H), 7.66 (d, J = 8.0Hz, 2H), 6.84 (s, 2H) ppm.

[0033] 13 C NMR (100MHz DMSO-d6): δ178.3,151.4,149.1,125.2,114.0ppm.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an aromatic ring acyl compound, characterized in that: The method comprises the following steps: adding an aromatic cyclopentyl compound, hydrated iron (III) oxide, an inorganic base, ethanol and water in a reactor in sequence, stirring and reacting for 20 to 40 minutes in air or oxygen, extracting and separating an organic phase after the reaction is complete, and drying and concentrating the organic phase to obtain a finished aromatic cyclopentyl.

2. The method for preparing an aromatic ring acyl compound according to claim 1, characterized in that: The molar ratio of the aromatic cyclopentane compound, hydrated iron (III) oxide and inorganic base is 1:1-4:1.5-3.

3. The method for preparing an aromatic ring acyl compound according to claim 1 or 2, characterized in that: The aromatic ring acyloin compound is benzoin or furanoin.

4. The method for preparing an aromatic ring acyl compound according to claim 1 or 2, characterized in that: The inorganic base is sodium hydroxide or potassium hydroxide or a mixture of the two.

5. The method for preparing an aromatic ring acyl compound according to claim 1, characterized in that: The volume ratio of the ethanol to water is 2 to 5:

1.

6. The method for preparing an aromatic ring acyl compound according to claim 1, characterized in that: When feeding, 1 to 3 mL of ethanol should be added for every 1 mmol of the aromatic cyclopentyl compound.

7. The method for preparing an aromatic ring acyl compound according to claim 1, characterized in that: The temperature of the stirring reaction is 0-130°C.

8. The method for preparing an aromatic ring acyl compound according to claim 7, characterized in that: The temperature of the stirring reaction is 0-35°C.

9. The method for preparing an aromatic ring acyl compound according to claim 1, characterized in that: The extraction is performed using saturated saline and ethyl acetate.

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