[Synthesis of pyrrolidine derivatives with pharmacological activity. IX. Synthesis of 1,1,5-trimethyl-2-ethyl- and 1,1,2,4,5-pentamethyl-3-diphenylmethylenepyrrolidinium iodide as potential anticholinergic agents (author's transl)]. - Ohki S; Yabe Y; Ozawa N; Hamaguchi F (Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 1976)