Synthesis and properties of 3-amino-2-(2-benzimidazolyl)-δ2-pyrrolizidin-1-one

2-Benzimidazotylacetonitrile is acetylated by the acid chloride derivative of N-trifluoroacetylproline to give N- and C-acyl derivatives. Removal of the trifluoroacetyl protective group in the C-acyl derivatives is accompanied by cyclization to give 3-amino-2-(2-benzimidazolyl)-Δ2-pyrrolizidin-1-one. Exhaustive acylation of this product gives a derivative of a new heterocyclic system, namely, pyrrolizino[3′,2′:5,6]-pyrimido[3,4-a] benzimidazole. ©1998 Plenum Publishing Corporation.