Design, Synthesis, and Antiviral Activity of Novel Chalcone Derivatives Containing a Purine Moiety

To find new antiviral agents, novel chalcone derivatives containing a purine moiety were designed and synthesized by combining bioactive substructures. The antiviral activities of the derivatives against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) were evaluated. Results showed that most of the derivatives showed antiviral activities. Compounds 3n and 3p exhibited excellent curative, protective and inactivation activities against TMV, with the EC₅₀ values of 452.4, 416.2, 241.2 and 438.7, 418.6, 261.7 µg•mL⁻¹, respectively, which were better than those of ribavirin (585.8, 436.0 and 268.7 µg•mL⁻¹). Compounds 3n and 3p showed remarkable curative and protective activities against CMV. Compound 3n showed a moderate affinity to TMV coat protein, with binding constant K_a and K_d values of 1.5 × 10⁴ L•mol⁻¹ and 79.8 µmol•L⁻¹, respectively. These findings provided an important structural insight for further designs of highly active chalcone derivatives and a basis for further study on their mechanism of action.