A kind of method of synthesizing 4-thiamphenicol toluene

Abstract

The invention discloses a method for synthesizing 4-methylsulfonyltoluene. The method comprises the following steps of mixing materials of a methyl sulfonylation reagent and phosphorus pentoxide to form a mixed solution, then respectively pumping the mixed solution and toluene into a mixer with an infusion pump at the same time, uniformly mixing the mixed solution and the toluene through the mixer, sending a mixture into a tubular reactor for reaction, installing a back pressure regulator at the tail end of the tubular reactor for regulating a pressure in a tube to enable a boiling point of the toluene to be not lower than a reaction temperature (70-170 DEG C) and a reaction retention time to be from 10mins to 4h, directly introducing a reaction solution into water after reaction is finished, and performing filtering and water washing to obtain the 4-methylsulfonyltoluene as a target product. The method has the advantages of high atom economy, high selectivity, simpleness in operation,good safety, high yield and the like and is very suitable for industrial production.

Description

technical field [0001] The invention relates to a method for synthesizing 4-thiamphenicol toluene. Background technique [0002] 4-thiamphenicol toluene is widely used in the synthesis of medical antibiotic thiamphenone toxin, veterinary antibacterial drug fluprofen, agricultural herbicide sulcotrione and important intermediates of organic synthesis, which has great value. According to the starting material, there are three synthetic methods: 1) Using 4-toluenesulfonyl chloride as raw material, reducing sodium sulfite to obtain sodium 4-methylbenzenesulfinate, and then methylating 4-methylbenzenesulfinate to obtain 4- Thymphenyltoluene (CN106432008A, CN105566181A, CN107089935A), the yield is 78%-82%, although the reagents used in this method are relatively cheap, but there are many operation steps and the reaction time is also long; 2) 4-methylthiotoluene is used as Raw material, hydrogen peroxide is oxidizing agent, oxidizes and obtains 4-thiamphenicol toluene under cataly...

AI Technical Summary

Problems solved by technology

The method has short steps and the yield is close to quantitative, but the raw materials and catalyst are expensive and the cost is high

3) Using toluene as a raw material, the mesylation reaction is directly carried out under the action of a catalyst, the literature ( J. Org. Chem.1999, 64 , 6479-6482) using methanesulfonyl chloride and methanesulfonic anhydride as sulfonation reagents, bismuth salt as catalyst, but the proportion of 4-position methanesulfonation products is only 65%, poor selectivity

[0003] Using toluene as a raw material to directly prepare 4-thiamphenicol toluene through mesylation reaction has cheap and easy-to-obtain raw materials, and the reaction atom economy is extremely high, but the existing methods either have poor selectivity or low conversion rate or use expensive catalysts, which are urgently needed need to improve