A method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis

Abstract

The present application relates to the fine chemical technology field, specifically to a kind of HI catalytic preparation 2-phenyl benzene-1,3-thioxin cyclohexene-4-ketone method.The yield of 2-phenyl benzene-1,3-thioxin cyclohexene-4-ketone synthesized by conventional method is low.For the above technical problem, the present application provides a kind of HI catalytic preparation 2-phenyl benzene-1,3-thioxin cyclohexene-4-ketone method, which is to add thiosalicylic acid, benzaldehyde, HI into organic solvent, and stir at a temperature higher than room temperature to obtain 2-phenyl benzene-1,3-thioxin cyclohexene-4-ketone.The raw materials in the method are easy to obtain, the operation is simple, the equipment requirement is low, the yield is as high as 95%, and it has good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine chemical technology, in particular to a method for preparing 2-phenylbenzo-1,3-thioxin-4-ketone by HI catalysis. BACKGROUND

[0002] 2-phenylbenzo-1,3-thioxin-4-ketone is an important organic sulfur-containing heterocyclic compound, which has significant biological activity, including insecticidal and antibacterial effects. In addition, the compound can also be used as a food additive.

[0003] At present, there are few methods for synthesizing 2-phenylbenzo-1,3-thioxin-4-ketone. The early synthesis method is mainly to use 2-benzylsulfonylbenzoic acid as raw material, and to prepare 2-phenylbenzo-1,3-thioxin-4-ketone by Pummerer reaction; then, 2-benzylthiobenzoic acid is used as raw material, and the product is prepared by adding Selectfluor or iodo-benzene diacetate. The defects of these methods mainly lie in the need to prepare 2-benzylsulfonylbenzoic acid and 2-benzylthiobenzoic acid in advance.

[0004] Recently, using benzene dithiol-3-ketone and benzaldehyde as raw materials, dichromium as metal catalyst, potassium carbonate and 1,2-bis(diphenylphosphine)ethane as additives, the target product can be quickly prepared, but the yield is low, only 45%.

[0005] Although there are literature reports that thiosalicylic acid and benzaldehyde are used as raw materials to prepare 2-phenylbenzo-1,3-thioxin-4-ketone, but the reported yield is only 33%, and no specific synthesis method is provided (Bulletin de la Societe Chimique de France, 1975, 206; Tetrahedron, 1980, 36, 3309).

[0006] Based on the above problems, a method for preparing 2-phenylbenzo-1,3-thioxin-4-ketone by HI catalysis of thiosalicylic acid and benzaldehyde is designed, which provides a new idea for the synthesis of this kind of active compound and has good potential application value. SUMMARY

[0007] The existing problem in the prior art is that the yield of 2-phenylbenzo-1,3-thioxin-4-ketone synthesized by conventional method is low. In view of the above technical problems, the present application provides a method for preparing 2-phenylbenzo-1,3-thioxin-4-ketone by HI catalysis, which comprises the following preparation steps:

[0008] Thiosalicylic acid, benzaldehyde, and HI are added to an organic solvent and stirred to react at a temperature higher than room temperature. After the reaction is completed, the reaction solution is purified to obtain 2-phenylbenzo-1,3-thioxadiene-4-one. The structural formula of the 2-phenylbenzo-1,3-thioxadiene-4-one is as follows:

[0009]

[0010] Ph in the above structural formula represents a benzene ring.

[0011] Preferably, the purification method is to concentrate the reaction solution and separate it by column chromatography.

[0012] Preferably, the reaction temperature is 40-120°C.

[0013] Preferably, the reaction temperature is 40°C.

[0014] Preferably, during the reaction, the molar ratio of thiosalicylic acid to benzaldehyde to HI is 0.2:0.2-0.6:0.04-0.3.

[0015] Preferably, the ratio of thiosalicylic acid to the organic solvent is 0.2 mmol:1-3 mL.

[0016] Preferably, the ratio of thiosalicylic acid to the organic solvent is 0.2 mmol:2 mL.

[0017] Preferably, during the reaction, the molar ratio of thiosalicylic acid to benzaldehyde and HI is 0.2:0.5:0.04.

[0018] Preferably, the organic solvent includes at least one of dichloromethane, chloroform, 1,2-dichloroethane, acetonitrile, ethyl acetate, anhydrous methanol, tetrahydrofuran, and dimethyl sulfoxide.

[0019] Preferably, the reaction time is 1 h.

[0020] The present invention has the following beneficial effects:

[0021] The present invention provides a method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis. The reaction raw materials are readily available, the operation is simple, the equipment requirements are low, the yield is as high as 95%, and the method has good application prospects. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the following examples. However, it should be understood that the following examples are merely illustrative of the embodiments of the present invention and are not intended to limit the scope of the present invention.

[0023] Example 1

[0024] Into a 25 mL vial, 2-mercaptopyridine (0.2 mmol, 25.6 mg), benzaldehyde (0.3 mmol, 31 μί), dichloromethane (2.0 mL), HI (0.2 mmol, 24 μί) were added in sequence, and the reaction was stirred at 100 °C. After 1 hour, the reaction was completed. After the reaction was completed, the reaction solution was concentrated and column chromatography was performed to isolate the product. 2-Phenylbenzo-1,3-thioxin-4-one was obtained in a yield of 60%. The structure of the target product was confirmed by1H NMR. The reaction process of the above reaction is as follows:

[0025]

[0026] The1H NMR data of the target product are as follows:

[0027] 1 1H NMR (300 MHz, CDC13) δ 8.22 (d, J = 8.0 Hz, 1H), 7.62-7.58 (m, 2H), 7.54-7.49 (m, 1H), 7.46-7.31 (m, 5H), 6.57 (s, 1H).

[0028] Screening of the amount of HI

[0029] Example 2 is the same as Example 1, except that the amount of HI in Example 2 is 0. 2-Phenylbenzo-1,3-thioxin-4-one was obtained in a yield of 0%.

[0030] Example 3 is the same as Example 1, except that the amount of HI in Example 3 is 0.04 mmol. 2-Phenylbenzo-1,3-thioxin-4-one was obtained in a yield of 65%.

[0031] Example 4 is the same as Example 1, except that the amount of HI in Example 4 is 0.1 mmol. 2-Phenylbenzo-1,3-thioxin-4-one was obtained in a yield of 60%.

[0032] Screening of the amount of benzaldehyde

[0033] Example 5 is the same as Example 3, except that the amount of benzaldehyde in Example 5 is 0.2 mmol. 2-Phenylbenzo-1,3-thioxin-4-one was obtained in a yield of 30%.

[0034] Example 6 is the same as Example 3, except that the amount of benzaldehyde in Example 6 is 0.4 mmol. 2-Phenylbenzo-1,3-thioxin-4-one was obtained in a yield of 70%.

[0035] Example 7 is the same as Example 3 except that in Example 7, 0.5 mmol of benzaldehyde is used. The yield of 2-phenylbenzo-1,3-thi- oxinium-4-one is 90%.

[0036] Example 8 is the same as Example 3 except that in Example 8, 0.6 mmol of benzaldehyde is used. The yield of 2-phenylbenzo-1,3-thi- oxinium-4-one is 89%.

[0037] Screening of solvent type

[0038] Example 9 is the same as Example 7 except that in Example 9, the same volume of chloroform is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 85%.

[0039] Example 10 is the same as Example 7 except that in Example 10, the same volume of 1,2-dichloroethane is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 80%.

[0040] Example 11 is the same as Example 7 except that in Example 11, the same volume of acetonitrile is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 80%.

[0041] Example 12 is the same as Example 7 except that in Example 12, the same volume of ethyl acetate is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 52%.

[0042] Example 13 is the same as Example 7 except that in Example 13, the same volume of anhydrous methanol is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 15%.

[0043] Example 14 is the same as Example 7 except that in Example 14, the same volume of tetrahydrofuran is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 0%.

[0044] Example 15 is the same as Example 7 except that in Example 15, the same volume of dimethyl sulfoxide is used instead of dichloromethane in Example 7. The yield of 2-phenylbenzo-1,3-thioxinium-4-one is 0%.

[0045] Screening of reaction temperature

[0046] Example 16 is the same as Example 7 except that the reaction temperature in Example 16 is 20 °C. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 0%.

[0047] Example 17 is the same as Example 7 except that the reaction temperature in Example 17 is 40 °C. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 95%.

[0048] Example 18 is the same as Example 7 except that the reaction temperature in Example 18 is 60 °C. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 93%.

[0049] Example 19 is the same as Example 7 except that the reaction temperature in Example 19 is 80 °C. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 90%.

[0050] Example 20 is the same as Example 7 except that the reaction temperature in Example 20 is 120 °C. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 85%.

[0051] Screening reaction time

[0052] Example 21 is the same as Example 17 except that the reaction time in Example 21 is 0.5 h. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 85%.

[0053] Example 22 is the same as Example 17 except that the reaction time in Example 22 is 3 h. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 80%.

[0054] Screening amount of solvent

[0055] Example 23 is the same as Example 17 except that the amount of dichloromethane in Example 23 is 1 mL. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 80%.

[0056] Example 24 is the same as Example 17 except that the amount of dichloromethane in Example 24 is 3 mL. The yield of 2-phenylbenzo-1,3-thioxin-4-one is 83%.

[0057] With the above ideal embodiments according to the present application as the inspiration, through the above description, relevant staff can make various changes and modifications without deviating from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the content in the specification, and must be determined by the scope of the claims.

Claims

1. A method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis, characterized in that: The method comprises the following preparation steps: Thiosalicylic acid, benzaldehyde, and HI are added to an organic solvent and stirred to react at a temperature higher than room temperature. After the reaction is completed, the reaction solution is purified to obtain 2-phenylbenzo-1,3-thioxadiene-4-one. The structural formula of the 2-phenylbenzo-1,3-thioxadiene-4-one is as follows: ， Ph in the above structural formula represents a benzene ring; The temperature is 40-120° C. During the reaction, the molar ratio of thiosalicylic acid to benzaldehyde and HI is 0.2:0.2-0.6:0.04-0.3; The organic solvent is at least one of dichloromethane, chloroform and 1,2-dichloroethane.

2. The method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis according to claim 1, characterized in that: The purification method is to concentrate the reaction solution and separate it by column chromatography in sequence.

3. The method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis according to claim 1, characterized in that: The reaction temperature was 40°C.

4. The method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis according to claim 1, characterized in that: The usage ratio of thiosalicylic acid to the organic solvent is 0.2mmol:1-3mL.

5. The method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis according to claim 4, characterized in that: The usage ratio of thiosalicylic acid to the organic solvent is 0.2 mmol:2 mL.

6. The method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis according to claim 1, characterized in that: During the reaction, the molar ratio of thiosalicylic acid to benzaldehyde and HI was 0.2:0.5:0.

04.

7. The method for preparing 2-phenylbenzo-1,3-thioxadiene-4-one by HI catalysis according to claim 1, characterized in that: The reaction time is 1h.

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