Study On The Synthesis Of Veratraldehyde And Its Derivatives

Veratraldehyde,also known as methyl vanillin,3,4-dimethoxybenzaldehyde,is a very important synthetic perfume,is also a very important organic synthetic intermediate,pharmaceutical intermediate,widely used in the synthesis and preparation of medicines,pesticides and other chemical products.The physicochemical properties of veratraldehyde and its application in medicine have stimulated people's interest in the research of its amino aromatic compounds.In this paper,veratraldehyde was synthesized from vanillin,and then veratraldehyde was brominated.The nitration of veratraldehyde,the reduction of nitration of veratraldehyde and the optimization of synthesis process were studied.Synthesis of veratraldehyde: Vanillin is used as raw material to dissolve in water,sodium hydroxide solution is added under the condition of heating and stirring,dimethyl sulfate is slowly added dropwise,the reaction temperature and pH value are monitored,and the appropriate raw material ratio,the appropriate reaction temperature and the appropriate acidity and basicity of the reaction are explored.Synthesis of nitrated veratraldehyde: acetic anhydride is used as solvent,temperature is controlled in ice-water bath,concentrated nitric acid is slowly added dropwise,water is washed after reaction,glacial acetic acid is washed,ethanol is recrystallized,and the yield is 92%.Synthesis of Amino veratraldehyde:(1)Ethanol and water are used as solvents,refluxing at 80?C,adding iron powder,dropping two drops of concentrated hydrochloric acid,filtering,washing with ethyl acetate,drying the washing liquid with anhydrous sodium sulfate,rotating to evaporate the solvent,and recrystallizing with nhexane and ethyl acetate,with a yield of 91.1%.(2)using ethanol and water as mixed solvents,reducing veratraldehyde by zinc powder,refluxing at 50-60?C,wherein the molar ratio of veratraldehyde to zinc powder is 1:4,the volume ratio of ethanol to water in the mixed solvent is 3: 2,and the yield is 88.8%;(3)ethanol is used as a solvent,veratraldehyde is added,Pd/C is added under heating and stirring,hydrazine hydrate is slowly added dropwise,hot water is filtered,warm water is washed,and solid crystallized by evaporating the solvent is recrystallized by ethanol/water.The synthetic route of 2-amino-6-bromo-3,4-dimethoxybenzaldehyde is as follows: veratraldehyde is dissolved in methanol,liquid bromine is added dropwise under heating and stirring,the temperature is controlled at 21-22 ?C,suction filtration and washing are carried out after the reaction till the pH value of the filtrate is close to neutral,and the filtered solid is recrystallized with ethanol,the yield is 75.6%.Then resveratrol bromide is used as a raw material,acetic anhydride is used as a solvent,concentrated nitric acid is used as a nitration reagent,concentrated sulfuric acid is used as a catalyst,ethyl acetate-petroleum ether phase is used for recrystallization,reduction reaction is carried out,nitro is reduced to amino,ethanol-acetic acid is used as a solvent,iron powder is used as a reducing agent,concentrated hydrochloric acid is used for catalysis,and 2-amino-6-bromo-3,4-dimethoxybenzaldehyde is obtained after posttreatment.In this paper,through the synthesis of veratraldehyde,the bromination of veratraldehyde,the synthesis of nitration reduction products and the improvement of the synthesis process,the synthesis methods of veratraldehyde derivatives such as veratraldehyde,bromination veratraldehyde,nitration veratraldehyde,etc.are preliminarily mastered,which lays a foundation for the synthesis and application of veratraldehyde in medicine.