Synthesis of pyrrolidine derivatives with pharmacological activity. XII Synthesis and anticholinergic activity of 1,1-dialkyl-3-diphenylmethylene-2,4-dimethylpyrrolidinium halides.

Several new 3-diphenylmethylene-2, 4-dimethylpyrrolidinium derivatives (2-6), structurally related to 3-diphenylmethylene-1, 1-diethyl-2-methylpyrrolidinium bromide (1) (Prifinium Bromide, an antispasmodic agent), were synthesized so as to examine the pharmacological effect of a methyl group at the 4-position of 3-diphenylmethylenepyrrolidinium salts. The stereochemistries of tertiary pyrrolidines (10-20) and quaternary pyrrolidinium salts (2-6) were confirmed on the basis of equilibrium reactions, Grignard reactions, and/or spectroscopic methods. The presence of a methyl group at the 4-position of 3-diphenylmethylenepyrrolidinium salts was found to reduce the anticholinergic activity.