Synthesis and conformational studies of short mixed γ/α-glycopeptides based on sugar γ 3,3 -amino acids

A spirocyclic backbone accesses new conformational space in an extended, dipole-stabilized foldamer

Most aromatic foldamers adopt uniform secondary structures, offering limited potential for the exploration of conformational space and the formation of tertiary structures. Here we report the incorporation of spiro bis-lactams to allow controlled rotation of the backbone of an iteratively synthesised foldamer. This enables precise control of foldamer shape along two orthogonal directions, likened to the aeronautical yaw and roll axes. XRD, NMR and computational data suggest that homo-oligomers adopt an extended right-handed helix with a pitch of over 30 Å, approximately that of B-DNA. Compatibility with extant foldamers to form hetero-oligomers is demonstrated, allowing greater structural complexity and function in future hybrid foldamer designs.

Synthesis of anti-proliferative [3.3.0]furofuranone derivatives by lactonization and functionalization of C-glycosyl compounds

The [3.3.0]furofuranone structure is found in numerous families of biologically active natural products. We took advantage of the stereodiversity afforded by carbohydrate derivatives to prepare several compounds structurally similar to goniofufurone and crassalactones which are natural cytotoxic agents. We designed and synthesized several stereoisomers of these natural compounds via lactonization of C-glycosyl compounds bearing an hydroxyl on position 4 and a methyl ester on the pseudo-anomeric positionThe reactivity of this bicyclic moiety was explored through etherification of hydroxyls in position 5 and 7 and various substituants (halogen, phenyl, benzyl, cynanmoyl) were introduced. The anti-proliferative properties of these mimics were then evaluated on various cancer cell lines and two compounds 24 and 35 demonstrated IC₅₀ value of 1.34 µM (U251) and 7.60 µM (U87) respectively.