Abstract
S-Alkylation of thiourea by the reaction with various alcohols has been investigated.
The reactions proceed in the presence of p-toluene-sulfonic acid (PTS), giving S-alkylisothiourea PTS salts (1).
The corresponding thiols were obtained by the hydrolysis of (1) in alkaline media.
The yields of butylisothiourea PTS salts were in the order of tertiary>secondary> primary, in contrast to that observed in the formation of butylisothiourea HBr salts from the reaction of butylbromides and thiourea.
The reaction seems to proceed by initial protonation of an alcohol by PTS to give a carbonium ion, which then attach itself by electrophilic addition to the sulfur atom.
