N-Me-Ile-OMe·HCl is a protected amino acid derivative, specifically the methyl ester hydrochloride salt of N-methyl-L-isoleucine. It serves as a crucial building block in solid-phase peptide synthesis (SPPS) and solution-phase peptide chemistry. The N-methylation of the amide bond introduces conformational constraints, which can significantly enhance the metabolic stability, membrane permeability, and biological activity of the resulting peptides. This compound is primarily used in the research and development of novel therapeutic peptides and peptidomimetics. The incorporation of N-methyl amino acids is a common strategy to combat enzymatic degradation and improve the pharmacokinetic profiles of peptide-based drugs. It finds application in the synthesis of complex natural products, peptide hormones, and constrained analogs for drug discovery programs targeting various diseases. As a high-purity chiral synthon, it is essential for constructing peptides with specific secondary structures. Handling requires standard precautions for amino acid derivatives and hydrochloride salts, including protection from moisture.