Fig. 3. (A) A key 1H homonuclear nOe correlation observed in 20 (solution in d6-DMSO). The distance between the highlighted hydrogens is approximately 5 Å in the desired conformation.† (B) X-ray crystal structure of the benzothiazole–thiophene scaffold 24.† The solid lines indicate the distances between the atoms on the scaffold that superimpose with the α-carbons at positions i, i + 4 and i + 7 of a canonical α-helix. The red dashed lines indicate the 1,5-S···O interactions. (C) Superposition of the scaffold with a canonical α-helix (residues 19–31 of pdb ; 1HLO). The β-carbons of the helix and corresponding atoms of the scaffold are shown as spheres. The ethylcarboxy substituent of the scaffold (R4) is truncated for clarity.
