An overview of the facile and high-yielding EDCI-mediated reaction of amines with N-Pmc-N′-alkyl thioureas to afford guanidines is presented, in which the general scope and limitations of the reaction are probed. It was found that the N-sulfonyl-N′-substituted thioureas cannot possess internal nucleophiles or disubstitution, and that the incoming amine must possess adequate nucleophilicity in order for the reaction to be viable. However, it is noted that the guanidine products can be accessed through two possible synthetic approaches, and that a simple reversal of amine and thiourea substituents allows the reaction to proceed successfully.
guanidine - guanylation - thiourea - EDCI -
N-sulfonyl
