3,4-二羟基-5-硝基苯甲醛的合成

Synthesis of 3,4-dihydroxy-5-nitrobenzaldehyde

香兰素经常温硝化、脱甲基两步反应制得了恩他卡朋的中间体(3,4-二羟基-5-硝基苯甲醛)。以65%的硝酸对香兰素进行硝化,制得5-硝基香兰素,收率81.2%。用无水三氯化铝和吡啶对5—硝基香兰素进行脱甲基,制得3,4-二羟基-5-硝基苯甲醛,收率96%。总收率78%。

The intermediate（3,4-dihydroxy-5-nitrobenzaldehyde） was prepared by using vanillin via two steps, including nitrification, demethylation. The vanillin was nitrified by using 65 % nitric acid to produce 5-nitrovanillin in 81.2 % yield. Next, the 5-nitrovanillin was demethylated by using anhydrous aluminum trichloride and pyridine to give（3,4-dihydroxy-5-nitrobenzaldehyde）, in the yield of 96 %. The total yield is 78 %.