The synthesis of <i>syn</i>‐ and <i>anti</i>‐2(<i>S</i>)‐phthalimido‐methyl‐2,3,4,4a,7,7a‐hexahydro‐6‐oxo‐5<i>H</i>‐pyrano‐[2,3‐<i>b</i>]pyrroles as rigid β‐bend peptide‐mimetics

Abstract

Abstract The synthesis of the syn ‐ 14 and anti ‐ 13 isomers of 2( S )‐phthalimidornethyl‐2,3,4,4a,7,7a‐hexahydro‐6‐oxo‐5 H ‐pyrano[2,3‐ b ]pyrrole was accomplished starting from sodium 3,4‐dihydro‐2 H ‐pyran‐2‐carboxylate. The isomers were separated by preparative high performance liquid chromatography. Both isomers can serve as β‐bend mimetics and represent three amino acids plus the amino group of the fourth amino acid of a peptide. The lactam nitrogen was alkylated to provide the equivalent of a leucine as the fourth amino acid residue.