Studies On Synthesis Of Aromatic Aldehyde Containing Electron Withdrawing Groups

Aromatic aldehydes are very important organic intermediates, which are wildly used in medicine, pesticides and other areas. This article outlines the types and different synthesis methods of a variety of aromatic aldehydes. After comparing with each method, and based on the concept of green chemistry, combined with low cost, high efficiency and less pollution, we introduced an improved synthetic method of aromatic aldehydes which containe elctronwithdrawing groups in ortho or para position or both of the aromatic ring.We used toluene substitutes which containe elctrowithdrawing groups in ortho or para position as a raw material,via reacting with N,N-dimethylformamide dimethyl-acetal(DMFDMA) to give styrylamine compounds, the styrylamine was oxidized under the presence of hydrogen peroxide and hydrolyzed under the presence of acid to give benzoic aldehydes and phenyl aldehydes respectively.By investigating and optimizing the influencing factors (such as the solvent, the temperature and the amount of hydrogen peroxide) on the enamine oxidation, the best yield of different benzoic aldehydes (2-nitro-4-chlorobenzaldehyde,2-chloro-4-nitro-benzaldehyde,4-Nitrobenzaldehyde,2-Nitrobenzaldehyde,4-Cyanobenzaldehyde) were 83.4%,75.3%,71.3%,85.3%,76.1%. By optimizing the hydrolysis conditions of enamines, the best yield of differentphenyl aldehydes (2-Nitro-4-chlorophenylacteal dehyde,2-Chloro-4-Nitrophenylacetaldehyde,4-Nitrophenylacetaldehyde,2-Nitrophen-ylacetaldehyde,4-Cyanophenylacetaldehyde) were 95.7%,86.1%,92.1%,96.8%, 84.1%.Compared with other methods, this synthesis route has the advantage of mild condition, high yields, less pollution and convenient operations. The main products were confirmed by 1H-NMR.