Study On The Synthesis Of 2,6-Dichlorobenzoxazole

Benzoxazole and its derivates have extensive biologic activity. They can be used as antiseptic, herbicide or insecticide on agriculture. 2, 6-dichlorobenzoxazole is di-chlorine substitute of benzoxazole, a very important intermediate.This paper relates to the processes for preparing the intermediate which can be employed for synthesis of active compounds, for example active compounds for crop protection agents, pharmaceuticals or dyestuff. As a result, the demand of 2,6-dichlorobenzoxazole is increasing.In this paper, 2, 6-dichlorobenzoxazole was prepared from cheap material o-aminophenol and urea in three steps. Firstly, the cyclization reaction of o-aminophenol with urea to give benzoxazolone is carried out in sulfuric acid. Secondly, the chlorination of benzoxazolone with hydrochloric and hydrogen peroxide is carried out in acetic acid. Lastly, the 6-chlorobenzolone is chloridized by phosphorus pentachloride in o-dichlorobenzene toget 2, 6-dichlorobenzoxazole.In contradistinction to the process hitherto known for preparing 2, 6-dichlorobenzoxazole, this paper is characterized by the fact that the yields are higher, the use of toxic and corrosive gases is avoided. Furthermore, the reaction products are so pure that it is unnecessary to precipitate or to recrystallize them. The simple procedure, higher yields and purity, and shorter reaction time are the advantages of the method.Structures of the products were primarily identified by TLC, IR and 'HNMR.