pyridinium p-toluenesulfonate in acetonitrile T=20 - 60°C; 72 h; Inert atmosphere;

trifluoroacetic acid; (S)-5,6-dimethyl-2-(pyrrolidin-2-yl)-1H-benzo[d]imidazole in tetrahydrofuran Robinson annelation; Title compound not separated from byproducts;