Semisynthesis\nof Nocarterphenyl A and Its Analogues

<i>p</i>-Terphenyl compounds are known to possess\na diverse\nrange of biological activities, making the synthesis of novel <i>p</i>-terphenyl derivatives a significant research objective.\nIn this study, we report the first synthesis of nocarterphenyl A (<b>1</b>), characterized by a thiazole-fused <i>p</i>-terphenyl\nframework. Furthermore, we synthesized 18 additional analogs, including\nthe naturally occurring compound 5-methoxy-4,7-bis(4-methoxyphenyl)benzo[<i>d</i>]thiazol-6-ol (<b>9</b>), employing a similar synthetic\napproach. Notably, compounds <b>12</b>, <b>13</b>, <b>15</b>–<b>17</b>, and <b>19</b> demonstrated\npotent inhibitory effects against protein tyrosine phosphatase 1B\n(PTP1B), exhibiting IC<sub>50</sub> values ranging from 2.2 to 7.9\nμM, which are lower than that of oleanolic acid (13.2 μM).\nAdditionally, compound <b>14</b> was found to inhibit α-glucosidase\nfrom human colorectal adenocarcinoma (Caco-2) cells with an IC<sub>50</sub> value of 10.4 μM, which is also lower than that of\nacarbose (11.2 μM).