通过将β-内酰胺缩合的1,3-苯并噻嗪环化成吲哚[2,3- b ] [1,4]苯并噻唑烷和吲哚[3,2- c ]异喹啉的新型吲哚合成
摘要:
事实证明,在非还原条件下,邻-硝基苯基取代的稠合1,3-苯并噻嗪是吲哚合成中有用的核心单元。因此,用甲醇钠在甲醇中处理邻-硝基-2-芳基-2a-氯-4 H-氮杂[2,1 - b ] [1,3]苯并噻嗪-1-酮提供了吲哚-1,4-苯并硫氮杂via通过新颖的重排。通过吲哚并[2,3- b ] [1,4]苯并硫氮杂卓的硫磺挤出反应,进一步获得了生物碱型吲哚衍生物,吲哚并[3,2- c ]异喹啉。新环系统的结构通过NMR光谱法确定。
Expected and unexpected reactions of 1,3-benzothiazine derivatives, I. Ring transformation of β-lactam-condensed 1,3-benzothiazines into 4,5-dihydro-1,4-benzothiazepines and indolo-1,4-benzothiazepines
The ring-enlargement reactions of monochloro-β-lactam-fused 2-aryl-1,3-benzothiazines revealed that the reactions of ortho-nitro aryl-substituted derivatives with sodium methoxide in methanol provided two products, depending on the amount of the base. With 2 equiv of reagent, the expected 1,4-benzothiazepines were obtained. Somewhat surprisingly, treatment with a large excess of sodium methoxide led