Cyclization of 1-alkyl-3-[(2Z)-2,4-diaryl-4-oxobut-2-en-1-yl]-1H-benzimidazol-3-ium bromides occurs in the presence of MeONa at a reduced temperature of 5–10°C via a 1,5-electrocyclization mechanism to give 3a,4-dihydro-3H-pyrrolo[1,2-a]benzimidazoles. These are unstable under the reaction conditions and are readily converted to 1-[2-(alkylamino)phenyl]-4-phenyl-1H-pyrrol-3-yl}(phenyl)methanones.
在MeONa的存在下,在低温下发生1-烷基-3-[(2Z)-2,4-二芳基-4-氧代丁-2-烯-1-基] -1H-
苯并咪唑-3-
溴化铵的环化反应通过1,5-电环化反应在5-10°C下生成3 a,4-二氢-
3H-吡咯并[1,2- a ]
苯并咪唑。它们在反应条件下是不稳定的,并且容易转化为1- [2-(烷基
氨基)苯基] -4-苯基-1H-
吡咯-3-基}(苯基)亚甲基。