Carbohydrate recognition of C 3 -symmetrical tripodal receptor-type 2,4,6-trisubstituted 1,3,5-triazine derivatives with antiviral activities

In our search for new bioactive compounds that interfere with the sugar recognition process, we have designed and synthesized C 3 - and Cs -symmetrical tripodal receptor-type molecules. Among the synthesized C 3 -symmetrical 2,4,6-trisubstituted 1,3,5-triazine (TAZ) derivatives, compounds A [2,4,6-tris(2-propoxy)-TAZ] and B [2,4,6-tris(3,4-dimethoxyphenyl)-TAZ] showed high levels of anti-HSV-1 activity. We carried out isothermal titration calorimetry on compound B ·HCl in aqueous 25% 2-PrOH solution with some sugar derivatives including methyl α/β- d -galactopyranoside (MeO-α/β-Gal), methyl α/β- d -mannopyranoside (MeO-α/β-Man) and methyl α/β- d -glucopyranoside (MeO-α/β-Glc). The reactions of compound B ·HCl with MeO-β-Gal and MeO-α-Man were exothermic, and the obtained thermodynamic profiles indicated that both reactions are spontaneous and that there is a considerably large enthalpic contribution (Δ H ) in total Gibbs free energy change (Δ G ), indicating favorable hydrogen bonding interactions. The reaction of compound B ·HCl showed a thermodynamic signature different from that of the entropically driven reaction of compound A .