This reagent, 1-N-Boc-2-Methyl-Isothiourea, is primarily used in organic synthesis for the preparation of N-Boc-protected guanidines from primary amines. It acts as a key building block in peptide synthesis, especially for incorporating arginine residues, and in the manufacture of pharmaceuticals containing guanidine moieties. The Boc (tert-butoxycarbonyl) group provides selective protection during multi-step reactions, safeguarding the guanidine functionality while allowing other groups to react, and can be deprotected under mild acidic conditions. This makes it invaluable for precise structural control in complex syntheses. Additionally, it serves as an intermediate in producing biologically active compounds, such as enzyme inhibitors and therapeutic agents.