5-甲氧基靛红的简便高效合成

The Highly Efficient Synthesis of 5-methoxy-isatin

从5-甲氧基苯胺出发,探索出了用Sandmeyer法两步合成目标分子5-甲氧基靛红的合成方法,找到了合成目标分子的最佳条件:以水为溶剂,在90℃条件下,5-甲氧基苯胺与水合氯醛,盐酸羟胺反应3.5 h,得到对甲氧基异亚硝基乙酰苯胺,产率95%.在92℃,浓H2SO4(75%)条件下环合,经水解后得到5-甲氧基靛红,产率为88%.使用该方法合成5-甲氧基靛红,反应操作简便高效.

Two-step synthesis of 5-MeO isatin using 5-MeO aniline with the method called Sandmeyer has been ex- plored. The optimum reaction condition for the synthesis of 2-（hydroxyimino）-N-（4-methoxyphenyl）acetamide is in water, three components 5-MeO aniline and chloral hydrate and hydroxylamine hydrochloride as bases have been reacting together at 90℃ for 3.5 hours, leading to the desired product in 95% yield. After acid hydrolysis with concentrated sulfuric acid（75%） at 92℃, 5-MeO isatin will be gained with 88% of yield. Therefore,with this highly efficient method, 5-MeO isatin can be prepared in a large scale in laboratory.