PYRROLO[1,4]DIAZEPINES, VIA THERMOLYSE OF CARBONYLAZIDES, AND [3,2,2]CYCLAZINES, VIA DIELS-ALDER REACTION OF [F]INDOLIZINES, ANNELATED TO [1]BENZOTHIOPHENE

摘要

Easy access to fused tricyclic pyrrolo[1,2-a][1]benzothieno[2,3-e][1,4] from the corresponding carbonyl azides by thermolysis in acetic acid is described. Moreover, new [1]benzothieno[2,3(3,2)-f]indolizines were synthesized in one-pot from 2(3)-(2-formylpyrrol-1-ylmethyl)-[1]benzothiophene and with diethyl acetylenedicarboxylate (DEAD) they led regiospecifically to [3,2,2] cyclazines fused to a [1]benzothiophene ring by 1,3-dipolar cycloaddition reaction rather than Diels-Alder adducts. Copyright (C) 1996 Elsevier Science Ltd [References: 19]