A highly efficient method for the synthesis of guanidinium derivatives

A high yielding synthesis of guanidiniums with the use of the ethyl carbamate protecting group is presented. This strategy eliminates many steric hindrance and electronic problems. The deprotection of the products by Me 3 SiBr is also demonstrated. The coupling of an amide to the ethyl carbamate-protected thiourea using EDCl resulted in high yield of guanidine and the subsequent complete deprotection of ethyl carbamate was carried out in Me 3 SiBr.