【摘要】 <正> 3-甲氧基-4-氯-5-硝基苯甲腈(5)是合成美登素的芳香核部分所用的一个中间体.从结构上看,由香兰素(1)来制备5是很值得尝试的.本文报道从1经四步反应制得了5,总产率为11％左右.我们过去由间-二硝基苯经2-甲氧基-6-硝基苯胺等六步反应制得5,总产率仅为7％左右. 1硝化得5-硝基香兰素(2).Grundon曾报道2在甲苯中与磷酰氯及N,N-二乙苯胺共同回流即可得3-甲氧基-4-氯-5-硝基苯甲醛(4).但我们按照其条件重复多次都不能得到所报道的结果,所得产物不是4而是3,即除酚羟基被氯代替外,醛基也已变更多还原

【Abstract】 The titled compound 3-methoxy-4-chloro-5-nitrobenzonitrile （5）, a useful ntermediate ur attempted synthesis of the C₉-N fragment of maytansine, was formerly prepared by us from -ethoxy-6-nitroaniline. We now report a new synthesis of it from vanillin.5-nitrovanillin （2）, hen refluxed with phosphoryl ohloride and s-collidine in toluene, gave 3-methoxy-4-ohloro-5-itrobenzylidene diohloride （3） instead of 3-methoxy-4-ohloro-5-nitrobenzaldehyde （4） as was eported by Grundon[4], while the reaction of 2 with thionyl ohloride and DMF at room emperature gave 3-methoxy-4-hydroxy-5-nitrobenzylidene diohloride （6）. 3 gave 4 when treated ith ooncentrated sulfuric acid at room temperature and 4 was converted to the desired oompound hen heated in 85% formic aoid with hydroxylamine hydrochloride and sodium formate.更多还原