CYCLIZATION OF META-PHENYLENE-BIS-ALANINE DERIVATIVES

The cyclisation of a meta-phenylene-bis-alanine derivative with severa l different spacer moieties was investigated. A large difference in th e ease of cyclisation was observed depending on which path of cyclisat ion was chosen. NMR studies indicate that the closed-loop molecules ad opt folded conformations with the loop directly above the aromatic rin g plane.