630403-65-5Relevant academic research and scientific papers
Studies in sulfur heterocycles. Part 16:1,2 synthesis of [1]benzothieno[3,2-b]pyrans via tandem reactions from 2,3-dihydrobenzo[b]thiophene-3(2H)ones
Kamila, Sukanta,Mukherjee, Chandrani,De, Asish
, p. 1479 - 1481 (2003)
Sequential treatment of N,N-diethyl-2-methylsulfanyl aryl amides with LDA and p-anisaldehyde, 1-naphthaldehyde and cinnamaldehyde afforded the corresponding thioaurones. Heating the 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.
