A new methodology for the synthesis of β-amino acids
作者:Mukund P. Sibi、Prasad K. Deshpande
DOI:10.1039/a908747h
日期:——
A differentially functionalized succinic acid unit 6 undergoes alkylation with excellent regio- and high stereocontrol at the carbon α to the imide to furnish the alkylated product 7 in 60â83% yield. Selective removal of the imide provides 8 in 80â90% yields. Curtius rearrangement of 8 with retention of stereochemistry provides N-protected β-amino acids (9) in 70â83% yields. Alternatively, selective deprotection of the ester group followed by Curtius rearrangement provides isomeric β-amino acids 14a, 14b, and 14e in good yields. The methodology has been successfully applied to the synthesis of N-Boc-iturinic acid and 2-methyl-3-aminopropanoic acid, components of the antifungal peptide iturin and the cytotoxic depsipeptide cryptophycin respectively.
tetradecanoic acid, a constituent amino acid of epichlicin, were synthesized as authentic standards. The stereochemistry of each amino acid was elucidated through a combination of the advanced Marfey method and chemical manipulation. Epichlicin showed inhibitory activity toward the spore germination of Cladosporium phlei, a pathogenic fungus of the timothy plant at an IC50 value of 22 nM.