Study On The Green Synthesis Of Cyclohenexone Based On Dihydropyran

Cyclohexenone as an important fine chemical intermediate is widely used in medicine,pesticides,spices,surfactants,polymer materials or other fields.Moreover,cyclohexenones are often used for the synthesis of carprofen,cyclohexenone herbicide,steroid compounds,and the substituted cyclohexenones are the intermediates of phenol derivatives.The synthtic methods of cyclohexenones include oxidation of cyclohexene,cyclohexanol,or cyclohexane.However,these methods are indeed not applied in industry.Therefore,an environmental friendly,low cost strategy for synthsizing cyclohexenone is urgent.In this paper,a green process for cyclohexenone synthesis from two different dihydropyrans was developed.Ethyl 2-butoxy-6-methyl-3,4-dihydro-2H-pyran-5-carboxylate was geneyarted by ethyl acetoacetate?1,3dicarbonyl derivatives?,formaldehyde,vinyl butyl ether at 80? for 5h;ethyl2-oxocyclohex-3-ene-1-carboxylatewassynthesizedbyethyl2-butoxy-6-methyl-3,4-dihydro-2H-pyran-5-carboxylate in the presence of PTSA,Ph₃PO and LiBr at 80? in CH₃CN;cyclohenexone was prepared by ethyl2-butoxy-6-methyl-3,4-dihydro-2H-pyran-5-carboxylate in water with the aid of HCl at 50^oC for 3 h.2-Methoxyprop-1-ene and acrolein was firstly were used to synthsize2-methoxy-2-methyl-3,4-dihydro-2H-pyran.The desired product clohexenone was then prepared by the obtained pyran with HCl in toluene at 80? for 5 h.