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 electrocyclicringclosure 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 ringclosure in one pot. Possible mechanistic pathways are discussed