Study On The Synthesis Of Furazolid

Furilazole,which chemical name is 2,2-dichloro-1-[5-（2-furanyl）-2,2-dimethyl-3-oxazolidine]-ethanon,is a dichloroacetyloxazolidine compound with potential herbicide safety properties.In the paper,Furilazole was prepared in 37.38%overall yield over four chemical steps of Henry reaction,reduction,cyclization and acylation by using furfural and nitromethane as the raw materials.The technological parameter such as reaction time,material ratio,reaction temperature,type of the catalyst and solvent were optimized.In the Henry reaction,the catalyst was determined as barium hydroxide octahydrate with the solvent of tetrahydrofuran.The reaction was carried out under 20 ℃ for 18 h to obtainα-（nitromethyl）-2-furanmethanol with the yield of 81.04%.In the process,the unreacted furfural was recovered using a saturated sodium bisulfite aqueous solution.In the reduction reaction,the catalyst was determined as 5%palladium carbon with the mass amount of 12%to the substrate.Methanol was employed as the solvent in the reduction with the reaction temperature below 40 ℃ and hydrogenation pressure of 10kg/cm³.The solvent used for the crystallization was selected and finally determined as dichloromethane.The yield of the reduction was 56.61%.In the cyclization and acylation,the"one-pot method"was used to synthesize oxapropazole and the type of acid binding agent was determined as sodium hydroxide.The solvent used in the cyclization and acylation was dichloromethane and the mole ratio ofα-（aminomethyl）-2-furan methanol:dichloroacetyl chloride:acetone:dichloromethane:sodium hydroxide was 1:1.3:7:8:2.2.In the cyclization and acylation,the reaction time was controlled to 3.5 h and the temperature was-5°C.The yield of one-pot was 81.17%.In the process,the structure of the product oxoxazole and key impurity impurity were separated and confirmed by ¹H NMR,¹³C NMR and HRMS.The route was simple to operate,green and environmentally friendly.The conditions were easy to control and the production cost was relatively low which was more suitable for industrial production.