A simple regioselective synthesis of pyrimido[1,2‐a]benzimidazoles

2-Aminobenzimidazoles were reacted with enaminones in acetic acid to give pyrimido[1,2-a]benzimidazoles. With a substituted enaminone only one regioisomer was obtained. Structural assignments based on nmr and uv spectroscopy are presented. Possible pathways leading to the products are discussed.