Conformational Analysis of 5-Membered Ring Compounds having Cholinergic Activity

A study of the conformational properties, both referred to the heterocyclic ring and to the ammonium sustituent, has been carried out on dimethylaminomethylmethiodide derivatives of 2-methyl substituted 5- membered satyrated hetrocycles having cholinergic activity. The experimental employed is NMR of the proton: the spectra were fully analyzed and all the multiplet parameters tentatively assigned. Vicinal coupling constants were employed for the conformational study by introducing them in a best fit procedure between experimental and calculated (by a semi-empirical method) values. The molecular conformation thus obtained were compared with results previously obtained for a few of the compounds here examined or for similar systems and employed for discussing the possible factors relating molecular geometry to their biological activity.