反应详情

As illustrated above in Scheme (A), the intermediate, 5,6-dimethoxy oxindole (I) is reacted with ethyl ortho formate (II) to provide 5,6-dimethoxy-3-hydroxymethylene oxindole (III). This oxindole (III) is then reacted with primary or secondary amines in refluxing benzene in the presence of acetic acid or toluene sulfonic acid to yield 5,6-dimethoxy-3-(substituted amino methylene) oxindoles (IV) or (V), respectively.