Studies in Sulfur Heterocycles.Part 16:Synthesis of [1]Benzothieno[3,2-<i>b</i>]pyrans via Tandem Reactionsfrom 2,3-Dihydrobenzo[<i>b</i>]thiophene-3(2<i>H</i>)ones
作者:Asish De、Sukanta Kamila、Chandrani Mukherjee
DOI:10.1055/s-2003-40825
日期:——
thioaurones derived from cinnamaldehyde, above 200 °C resulted in electrocyclic ring closure and sigmatropic shift in tandem to give substituted [1]benzothieno[3,2-b]pyran. Treatment of N,N-diethyl-2-methylsulfanyl-5-methoxy benzamide and crotonaldehyde gave 4-methyl-8-methoxy[1]benzothieno[3,2-b]pyran via conjugate nucleophilic addition and ring closure in one pot. Possible mechanistic pathways are discussed
用 LDA 和对茴香醛、1-萘醛和肉桂醛依次处理 N,N-二乙基-2-甲基硫烷基芳基酰胺,得到相应的硫代金黄酮。将肉桂醛衍生的硫代醛酮加热到 200 °C 以上,导致电环闭合和串联向西偏移,得到取代的 [1] 苯并噻吩并 [3,2-b] 吡喃。N,N-二乙基-2-甲基硫烷基-5-甲氧基苯甲酰胺和巴豆醛通过共轭亲核加成和一锅闭环得到4-甲基-8-甲氧基[1]苯并噻吩并[3,2-b]吡喃。讨论了可能的机械途径。