Synthesis of new N,N-disubstituted 4-amino-5,6-dihydro-3-phenyl-2H-thieno[2,3-h]-1-benzopyran-2-ones.
The synthesis of some N,N-disubstituted 4-amino-5,6-dihydro-3-phenyl-2H-thieno[2,3-h]-1-benzopyran-2-ones (4a-f), by reaction of phenylchloroketene with a series of N,N-disubstituted (E)-5-aminomethylene-6,7-dihydrobenzo[b]thiophen-4(5)-ones, followed by dehydrochlorination in situ of the primary adducts with DBN, is described. A moderate local anaesthetic activity was observed in the title compounds, particularly in 4e.