Abstract:

α-Alloenduracididine 3-(2-amino-4,5-dihydro-1Himidazole- 4-yl)-2-aminopropionic acid) 1 and its diastereoisomer, enduracididine 2, are two nonproteinogenic amino acids isolated in 1968 from Streptomyces fungicidicus as part of a cyclopeptide the enduracidine, which has antibiotic activity. α-Alloenduracididine, which can be viewed as a constrained analogue of arginine 3, belongs to a family of natural amino acids having the terminal guanidine nitrogen atom linked to the methylene backbone. Most of these amino acids are components of peptide antibiotics isolated from extracts of microorganisms and include: β-hydroxyenduracididine and β- hydroxyalloenduracididine (constituents of (α-ε)- mannopeptimycins) tetrahydrolathyrine, capreomycidine (constituent of capreomycins).Our laboratory has recently completed the first total synthesis and determination the absolute configuration of tetrahydrolathyrine. Here, we report the synthesis of an advanced intermediate of a- alloenduracididine.