A Study On Synthesis Of A Series Of Salicylaldehyde

Aromatic aldehydes compounds as an important intermediate in industry of fine chemicals. Especially salicyladehyde not only in medicine, dyes, agricultural pesticides, spices have a wide range of applications, but also can form Schiff's Bases with the Secondary Amines, which is a important ligand of metal complex. And it is widely used in vinyl epoxidation, asymmetric cyclopropanation, kinetic resolution, asymmetric cyanide silylation, Diels-Alder cycloaddition and other fields.In this study, we have synthesized a series of aromatic aldehydes from phenol and substituted phenols. we through analysis of reaction mechanism and do a lot of research, finally get a new type of improved Duff aldehydes syntheis, compared with the literature that the method has the advantage of simple reaction conditions,the yield is much higher than original method. In this way a series of salicylic aldehydes was synthesized: 3,5-di-tert-butyl salicylaldehyde,3,5-dimethyl salicylaldehyde,5-methoxy- salicylaldehyde,2-hydroxy-3-benzaldehyde,2-hydroxy-1-naphthaldehyde,5- formyl salicylic acid,3-formyl-4-hydroxy benzoic acid,5-fluorosalicylaldehyde,5-nitro-salicylaldehyde,3-nitro- salicylaldehyde,salicylaldehyde,3-sec-butyl- 2-hydroxybenzaldehyde.This article also through methanol magnesium reaction prepared two kinds of aldehydes: 5-methoxy- salicylaldehyde,salicylaldehyde. Through experiments we have found that the methanol magnesium is very suitable for small sterically hindered phenols to ortho-formylation, with high yield, the product will not bring other impurities, is suitable for application fields of medicine and spices.On the basis of the work that predecessors had done, we through analysis of reaction mechanism and do a lot of research, we finally invention a new improved Duff aldehyde synthesis .We through formylation the intermediate-Schiff's Base, reduce the rate of Schiff's Base which will be transformation ammonium sulfate and taken away by water. This approach has never been reported previously .We also found the effects of varying molar ratios, temperature, time, solvent, etc. may seriously influence yields.