SEARCH Articles Figures Tables Acylation Hoesch HOUBEN-HOESCH Hoesch Houben Houben-Hoesch pyrrole acylation Houben-Hoesch pyrrole acylation Lewis acids Houben-Hoesch pyrrole acylation Nitriles Houben-Hoesch pyrrole acylation Pyrrole, 3- acylation Pyrrole, 3-acyl