SYNTHESIS OF AZULENO[1,2-<i>b</i>]- AND AZULENO[1,2-<i>c</i>]THIOPHENES BY THE REACTIONS OF 2<i>H</i>-CYCLOHEPTA[<i>b</i>]FURAN-2-ONES WITH ENAMINES OF 3-OXOTETRAHYDROTHIOPHENES
New heterocyclic compounds, azuleno[1,2-b]- and azuleno[1,2-c]thiophene, are synthesized by the reaction of 3-methoxycarbonyl-2H-cyclohepta[b]furan-2-one with morpholino enamines of 3-oxotetrahydrothiophene, followed by dehydrogenation of resulting dihydrocompounds with 2,3-dichloro-5,6-dicyano-p-benzoquinone.
1,5- And 1,7-azulenequinones fused with a thiophene or furan ring have been synthesized by bromine oxidation of azuleno[1,2-b]thiophenes, azuleno[2,1-b]thiophene, and azuleno[1,2-b]furan in aqueous THF.