Synthesis Of Antifungal Cinnamaldehyde Derivatives And Quantitative Structure-Activity Relationship

Wood is a kind of renewable natural material; its processing products are widely used in people’s daily life. However, wood is susceptible to degradation caused by decay fungi and insects, it is the main reason which limits the use of wood. Traditional wood preservatives can greatly extend the service life of wood, but they could cause serious environmental pollution, and harmful to human. Therefore, development of new environmentally friendly, human benign wood preservatives becomes the development trend of the wood preservation industry.Cinnamaldehyde is the major constituent of cinnamon essential oil, has good antifungal activity. But the properties of volatile and strong smell of cinnamon and hydrophobicity restrict the use of cinnamaldehyde in wood protection field.In order to over came the shortcoming mentioned above, cinnamaldehyde was used as the raw material to produce o-Nitrocinnamaldehyde and a-Bromocinnamaldehyde, which have odourless, and also generate cinnamaldehyde hydroxyl sulfonic sodium, which has great water solubility and odourless. The chemical structure of o-Nitrocinnamaldehyde and a-Bromocinnamaldehyde were identified by FTIR and NMR. The chemical structure of cinnamaldehyde hydroxyl sulfonic sodium was identified by FTIR. The anti-fungal activity of the three products was determined by paper-disc method with wood stain fungi such as Aspergillus niger, Paecilomyces Variotii and Paecilomyces lilacinus. The results indicated that o-Nitrocinnamaldehyde has certain inhibition effect on this three selected wood mould, but the anti-fungal activity was obviously decrease compared with cinnamicaldehyde. The anti-fungal experiment results showed that cinnamaldehyde hydroxyl sulfonic sodium has a little anti-fungal activity for the selected fungal, especially Aspergillus niger, but the antifungal activity of the product is not good. The anti-fungal experiment of α-Bromocinnamaldehyde indicated that the product has excellent inhibition effect on this three selected fungi, and when the concentration is2mg/mL, the Paecilomyces lilacinus was totally inhibited, and it also showed the good inhibition to Aspergillus niger and Paecilomyces Variotii.In order to make the relationship between structure and activity of cinnamaldehyde more explicit, a quantitative structure-activity relationship (QSAR) modeling of the antifungal activity of cinnamaldehyde analogues against of Aspergillus niger and Paecilomyces Variotii was presented. The molecular descriptors of cinnamaldehyde analogues were calculated by the Codessa program, and these descriptors were selected by best multi-linear regression method (BMLR). Satisfactory multilinear regression models of Aspergillus niger and Paecilomyces Variotii were obtained with R2=0.9099and0.9444, respectively. The models were also satisfactorily validated using internal validation and leave one out validation. Used the models to predict the activity of N. N·-bis(trans-cinnamaldehyde)-1.2-diiminoethane against Aspergillus niger and Paecilomyces Variotii, the results indcated that N, N’-bis(trans-cinnamaldehyde)-1,2-diiminoethane had good anti-fungal activity against these two mould.Cinnamaldehyde was used as the raw material, take place reaction with ethylenediamine in ice water bath, produce N, N’-bis(trans-cinnamaldehyde)-1,2-diiminoethane which has long chain and more, benzene rings. The anti-fungal experiment showed that the product has good antifungal activity to Aspergillus niger, Paecilomyces Variotii and Paecilomyces lilacinus, it has the similar effect to cinnamicaldehyde. Paecilomyces Variotii has the similar logAR with the predict number.Benzaldehyde,p-methoxy cinnamaldehyde and p-Chlorocinnamaldehyde were used as the raw materials, ethanol as the solvent take place reaction with ethylenediamine at reflux condition for20h,2h and2h, respectively. The antifungal experiment showed that he products have certain antifungal activity to Aspergillus niger, Paecilomyces Variotii and Paecilomyces lilacinus, and N, N’-bis(p-methoxy cinnamaldehyde)-1,2-diiminoethane has the best antifungal activity compared with the other two products.