Quantitative ion-exchange chromatography was used to establish that intratransguanylation is dependent on pH as well as on the number of carbon atoms between the amino and isothiourea groups. The aminoethyl- and aminopropylisothioureas intratransguanylate readily at neutral pH but 5,4- aminobutylisothiourea does not. At pH's 3--6, 2-aminothiazolines and - penthiazolines are formed, whereas in strong ailali, mixtures of mercaptoguanidines and mercaptoamines are formed. NAlkyl substitution on the various N atoms alters the pH at which intratraanguanylation takes place as well as the rate of formation and composition of the products obtained. (auth)