.5 The - Nitrosalicylaldehyde Synthetic Methods

Summarize the researching work of synthesis 5-nitrosalicylalydehyde by two methods in the paper.Firstly, take salicylaldehyde as the original material, observing the effect of ratio of raw materials time and temperature on the direct nitrifing reaction. Mixture of 3-nitrosalicylaldehyde and 5-nitrosalicylaldehyde are obtained, 54.1% 5-nitrosalicylaldehyde and 41.3 % 3-nitrosalicylaldehyde determined by HPLC in it. After adding PPA as catalyst, ratio of 5-/ 3- nitrosalicylaldehyde promoted from 1.31/1 to 1.7/1.According to the solution difference 3-and 5-nitrosalicylaldehyde sodium salts in water, the sodium salt of 3-and 5-nitrosalicylaldehydes are separated by extraction with water. Then their sodium salt solutions were acidified and recrystallized separately. 5-Nitrosalicylaldehyde was obtained in 49.5% yield and purity was 98% as determined by HPLC. 3-Nitrosalicylaldehyde was obtained in 35% yield.Secondly, take p-nitrophenol as the raw material, studing the effect of Duff formylation reaction. Water was found harmful to the Duff reaction. So using PPA as acid media can accelerate formylation process. 5-Nitrosalicylaldehyde was obtained in 51% yield.Structure determined by IR UV MS and 1HNMR...