Simple and efficient methodology to prepare guanidines from 1,3-disubstituted thioureas

[Display omitted] •KICl2 was used to obtain guanidinium salts from 1,3-disubstituted thioureas.•Cyclic/acyclic guanidines (hydrochloride salt) were obtained in high chemical yields.•The aqueous solution of KICl2 offers advantages in terms of safety and ease of use. Guanidinium salts were efficiently prepared by desulfurization reactions of 1,3-disubstituted thioureas using KICl2 in the presence of amines. The reactions were successfully carried out at room temperature, in short reaction time, affording cyclic/acyclic guanidines (hydrochloride salts) in high chemical yields.