3-(5-Methylfuran-2-yl)propanoic acid is a synthetic, non-proteinogenic amino acid characterized by a standard three-carbon propanoic acid backbone with an amino functional group (-NH2) located at the alpha-carbon (C2) and a distinctive 5-methylfuran-2-yl substituent at the beta-carbon (C3), where the furan ring—a five-membered aromatic heterocycle containing an oxygen atom—provides its unique structural and electronic properties, distinguishing it from canonical amino acids.