Synthesis of Antioxidative p-Terphenyl Dimers via Boronic Acid-Mediated C–C Coupling

By investigating the conditions for the C-C coupling reaction of <i>p</i>-terphenyls, we successfully synthesized C-C coupled dimeric <i>p</i>-terphenyls for the first time using a reaction system involving air, silica gel, and B(OH)₃. Additionally, we developed a novel method to synthesize furan-fused <i>p</i>-terphenyl dimers through solvent-free reactions by creatively applying rotary evaporation and heating. Compounds <b>6</b>-<b>12</b>, <b>16</b>, <b>20</b>, and <b>22</b> demonstrated DPPH radical scavenging activity that was either stronger than or comparable to the positive control (vitamin C), with IC₅₀ values ranging from 0.14 to 4.61 μM. Compounds <b>4</b>-<b>22</b> also exhibited significant activity against α-glucosidase, with IC₅₀ values ranging from 0.37 to 17.9 μM, exceeding the efficacy of the positive control, acarbose. Moreover, compounds <b>6</b>-<b>14</b>, <b>16</b>-<b>18</b>, <b>21</b>, and <b>22</b> demonstrated greater inhibitory activity against PTP1B compared with the positive control, oleanolic acid, with IC₅₀ values between 0.30 and 9.17 μM. These findings highlight their potential as promising leads or dietary supplements for the treatment and prevention of diabetes, as well as possible application as oxidative agents in food preservation.