Siberian Federal University

The article discusses the existing methods for obtaining dihydro derivatives of substituted arenes by reducing various functional derivatives of benzene (toluene, cumene, o- and p-cymene, o- and p-xylene, anisole, 2-methylanisole, 3-methylanisole, 4-methylanisole, methyl ether thymol, o- and p-cymen-9-ol). The authors propose an improved method for the preparation of 2,5-dihydro derivatives of aromatic compounds in the arene–lithium–isopropanol–ethylenediamine reducing system at their molar ratio of 1: 2–6: 4–12: 0.25–0.5, respectively. It has been established that the reduction time of one mole of the initial arene is no more than one hour at a process temperature of 75–85 °C. The conversion reaches 90–96 %. The content of 2,5-dihydro derivatives of arenes in the reaction products ranges from 80 to 96 %, depending on the structure of the starting arene. This method has a low content of aliphatic amine in comparison with existing analogues. For the first time, this method was used to reduce cumene, o-para-isomers of xylene, and thymol methyl ester. 2,5-Dihydro derivatives of aromatic compounds are formed in high yield, and the reduction process itself is technologically easy to implement in practice in laboratory conditions and industry. The reaction products were identified by gas-liquid chromatography on an LKhM-6MD chromatograph with a flame ionization detector