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

TL;DR

Researchers synthesized new p-terphenyl dimers with strong antioxidant and enzyme-inhibiting properties, showing potential for diabetes treatment and food preservation.

Contribution

First-time synthesis of C–C coupled p-terphenyl dimers and a novel solvent-free method for furan-fused dimers.

Findings

Compounds 6–12, 16, 20, and 22 showed DPPH radical scavenging activity comparable to or stronger than vitamin C.

Compounds 4–22 exhibited stronger α-glucosidase inhibition than acarbose, a known positive control.

Several compounds demonstrated superior PTP1B inhibitory activity compared to oleanolic acid.

Abstract

By investigating the conditions for the C–C coupling reaction of p-terphenyls, we successfully synthesized C–C coupled dimeric p-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 p-terphenyl dimers through solvent-free reactions by creatively applying rotary evaporation and heating. Compounds 6–12, 16, 20, and 22 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 4–22 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 6–14, 16–18, 21, and 22 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.

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