阅读说明：本技术 一种苯并呋喃-2(3h)-酮的合成方法 (Synthetic method of benzofuran-2 (3H) -ketone ) 是由 黄崇琛 于 2019-10-18 设计创作，主要内容包括：本发明涉及一种苯并呋喃-2(3H)-酮的合成方法,以叔丁基苯酚和乙二醛为原料,以乙酸为溶剂,以液体酸为催化剂,合成得到叔丁基苯并呋喃,再将叔丁基苯并呋喃进行脱叔丁基反应得到目标产物苯并呋喃-2(3H)-酮。本发明合成路线简单,反应条件温和,不采用氯气等有毒物质,也不需要多次酸碱中和,能够满足绝色环保的要求。(The invention relates to a synthesis method of benzofuran-2 (3H) -ketone, which comprises the steps of taking tert-butyl phenol and glyoxal as raw materials, taking acetic acid as a solvent and liquid acid as a catalyst to synthesize tert-butyl benzofuran, and then carrying out tert-butyl removal reaction on the tert-butyl benzofuran to obtain a target product benzofuran-2 (3H) -ketone. The invention has simple synthetic route and mild reaction condition, does not adopt toxic substances such as chlorine and the like, does not need acid-base neutralization for many times, and can meet the requirement of top-off color and environmental protection.)

1. A synthetic method of benzofuranone-2 (3H) ketone is characterized by comprising the following steps:

2. the method of synthesis according to claim 1, comprising the steps of:

1) tert-butyl phenol and glyoxal are used as raw materials, acetic acid is used as a solvent, liquid acid is used as a catalyst, and tert-butyl benzofuranone is obtained by separation from a synthetic product;

2) dissolving tert-butyl benzofuranone obtained in the step 1) in a toluene solvent, adding aluminum trichloride as a catalyst for refluxing, and performing a tert-butyl removal reaction to obtain a reacted material;

3) cooling the material obtained in the step 2) to normal temperature, slowly adding water and stirring, layering after stopping stirring, separating and taking an oil layer, and performing reduced pressure rectification to obtain the benzofuran-2 (3H) -one.

3. The synthesis method of claim 2, wherein the molar ratio of the tert-butyl phenol to the glyoxal in the step 1) is 1 (0.5-2).

4. The synthesis method according to claim 2, wherein the mass ratio of tert-butyl phenol to acetic acid in step 1) is (10-40): 100.

5. The synthesis method according to claim 2, wherein the mass ratio of glyoxal to acetic acid in step 1) is (10-40): 100.

6. the synthesis method according to claim 2, wherein the mass ratio of the liquid acid catalyst to the acetic acid in the step 1) is (1-5): 100.

7. the synthesis process according to any one of claims 1 to 6, wherein in step 1) the ratio of tert-butylphenol: glyoxal: the molar ratio of the liquid acid catalyst is 1: (1.1-1.2): (0.05-0.1).

8. The synthesis method as claimed in claim 7, wherein the reaction conditions in step 1) are that the reaction is carried out at 100-150 ℃ for 20-50min, and the glyoxal is added dropwise during the reaction.

9. The method of synthesis according to claim 2, comprising the steps of:

1) tert-butyl phenol and glyoxal are used as raw materials, acetic acid is used as a solvent, and liquid acid is used as a catalyst, wherein the mass ratio of tert-butyl phenol: glyoxal: the molar ratio of the liquid acid catalyst is 1: (1.1-1.2): (0.05-0.1) at the reaction temperature of 90-120 ℃, cooling the reacted materials after full reaction, and filtering and separating to obtain tert-butyl benzofuranone with the yield of more than 80%;

2) dissolving the tert-butyl benzofuranone obtained in the step 1) in a toluene solvent, adding aluminum trichloride as a catalyst for refluxing, and performing a tert-butyl removal reaction, wherein the tert-butyl benzofuranone: the molar ratio of the aluminum trichloride is 1: (0.5-1) to obtain a material after reaction;

3) cooling the material obtained in the step 2) to normal temperature, slowly adding water and stirring, separating after stopping stirring, separating an oil layer, and performing reduced pressure rectification to obtain the benzofuran-2 (3H) -one, wherein the yield is over 80 percent, and the purity is over 99 percent.

Technical Field

The invention relates to the field of organic synthesis, in particular to a synthetic method of benzofuran-2 (3H) -ketone.

Background

Benzofuran-2 (3H) -one is an important fine chemical intermediate, and is an important raw material for producing azoxystrobin and other medicaments. The existing industrial synthesis route of benzofuran-2 (3H) -ketone mainly comprises the following steps: chlorination of toluene benzene ring to obtain o-chlorotoluene; the o-chlorotoluene is subjected to side chain chlorination to obtain o-chlorobenzyl chloride; reacting o-chlorobenzyl chloride with sodium cyanide to obtain o-chlorobenzyl acetonitrile, alkalifying and acidifying the o-chlorobenzyl acetonitrile to obtain o-hydroxyphenylacetic acid; cyclizing and esterifying o-hydroxyphenylacetic acid to obtain benzofuran-2 (3H) -one, and distilling to obtain the final product.

CN107417652A discloses a synthesis process of azoxystrobin intermediate benzofuranone, which comprises the following steps: 1) putting raw material o-chlorophenylacetic acid into a synthesis kettle, adding a catalyst and liquid caustic soda into the synthesis kettle, and heating; 2) after the reaction of the synthesis kettle is finished, cooling the temperature of the synthesis kettle; 3) filtering the materials in the synthesis kettle cooled to room temperature, and filtering to recover the catalyst; 4) transferring to a cyclization kettle, adding a catalyst and toluene, heating, and carrying out reflux reaction; 5) adding water into the material after the reflux is finished to wash impurities in the material, and transferring the organic phase into a concentration kettle for concentration; 6) and concentrating the mixture to obtain a certain amount of toluene, namely the toluene solution of benzofuran.

CN109651315A discloses a synthesis process of methoxybenzofuranone, which comprises the following specific steps: putting trimethyl orthoformate, benzofuranone and acetic anhydride into a full-synthesis kettle, removing methyl acetate, and transferring to a deacidification kettle; vacuumizing a deacidification kettle, removing acetic acid at the temperature of 80 ℃, transferring to a dissolving kettle after the deacidification kettle is finished, putting toluene into the dissolving kettle, fully stirring, transferring the organic layer material to an alkaline washing kettle for alkaline washing, washing with water after the alkaline washing is finished, finally performing desolventizing, and transferring the material to a metering tank after the desolventizing. In the process, a byproduct methyl acetate is distilled and recovered while the reaction is carried out, and then deacidification, extraction, alkali washing and water washing are respectively carried out, and finally desolventization is carried out.

However, the synthesis process needs to be complicated, highly toxic raw materials such as chlorine and sodium cyanide are needed in the reaction process, and acid and alkali are neutralized for many times in the process, so that a great amount of pollution is generated. Therefore, it is an urgent technical problem to provide a new synthesis method with simple reaction conditions, mild reaction process and high product selectivity.

Disclosure of Invention

In order to solve the technical problems, the invention provides a brand-new synthesis method of benzofuran-2 (3H) ketone, which takes tert-butylphenol as a raw material and obtains the benzofuran-2 (3H) ketone through two steps of condensation reaction and dealkylation reaction. The method has the advantages of short synthetic route, great saving of synthetic cost, mild reaction process, high safety, high product selectivity and great reduction of pollutant generation in the synthetic reaction process.

The invention provides a synthetic method of benzofuranone-2 (3H) ketone, which comprises the following steps:

further, the synthesis method comprises the following steps:

1) tert-butyl phenol and glyoxal are used as raw materials, acetic acid is used as a solvent, liquid acid is used as a catalyst, and tert-butyl benzofuranone is obtained by separation from a synthetic product;

2) dissolving tert-butyl benzofuranone obtained in the step 1) in a toluene solvent, adding aluminum trichloride as a catalyst for refluxing, and performing a tert-butyl removal reaction to obtain a reacted material;

3) cooling the material obtained in the step 2) to normal temperature, slowly adding water and stirring, layering after stopping stirring, separating and taking an oil layer, and performing reduced pressure rectification to obtain the benzofuran-2 (3H) -one.

Further, the molar ratio of the tert-butyl phenol to the glyoxal in the step 1) is 1 (0.5-2).

Further, the mass ratio of the tert-butyl phenol to the acetic acid in the step 1) is (10-40): 100.

Further, the mass ratio of the glyoxal to the acetic acid in the step 1) is (10-40): 100.

further, the mass ratio of the liquid acid catalyst to the acetic acid in the step 1) is (1-5): 100.

preferably, the tert-butylphenol ratio in step 1): glyoxal: the molar ratio of the liquid acid catalyst is 1: (1.1-1.2): (0.05-0.1).

Further, the reaction conditions in the step 1) are that the reaction is carried out for 20-50min at the temperature of 100-150 ℃, and the glyoxal is dropwise added in the reaction process.

Further, the liquid acid catalyst in step 1) comprises sulfuric acid, hydrochloric acid and/or phosphoric acid.

More preferably, the synthesis method comprises the following steps:

1) tert-butyl phenol and glyoxal are used as raw materials, acetic acid is used as a solvent, and liquid acid is used as a catalyst, wherein the mass ratio of tert-butyl phenol: glyoxal: the molar ratio of the liquid acid catalyst is 1: (1.1-1.2): (0.05-0.1) at the reaction temperature of 90-120 ℃, cooling the reacted materials after full reaction, and filtering and separating to obtain tert-butyl benzofuranone with the yield of more than 80%;

2) dissolving the tert-butyl benzofuranone obtained in the step 1) in a toluene solvent, adding aluminum trichloride as a catalyst for refluxing, and performing a tert-butyl removal reaction, wherein the tert-butyl benzofuranone: the molar ratio of the aluminum trichloride is 1: (0.5-1) to obtain a material after reaction;

3) cooling the material obtained in the step 2) to normal temperature, slowly adding water and stirring, separating after stopping stirring, separating an oil layer, and performing reduced pressure rectification to obtain the benzofuran-2 (3H) -one, wherein the yield is over 75 percent, and the purity is over 99 percent.

The invention has the beneficial effects that:

1. compared with the synthetic route which is at least subjected to 5 reaction steps in the prior art, the synthetic route is short, the tert-butyl phenol and glyoxal react to synthesize tert-butyl benzofuranone, and tert-butyl is removed from the tert-butyl benzofuranone to obtain the target product benzofuran-2 (3H) -one;

2. compared with the synthetic route in the prior art, the synthetic method has the advantages that the reaction process is short, the reaction condition is mild, highly toxic substances such as chlorine gas and sodium cyanide are not used, multiple acid-base neutralization is not needed, a large amount of pollutants are not generated, and the requirement of environmental protection can be met;

3. compared with the synthetic route in the prior art, the method has the advantages that the target product is obtained and then a complex purification process is needed, the product has high purity due to the innovative synthetic route, and the comprehensive reaction yield and the product purity are superior to those of the synthetic route in the prior art.

Detailed Description