Synthesis of C3′‐Foused Aryl/Penta‐1,4‐dien‐3‐one/Amine Hybrids as HSP90 C‐Terminal Inhibitors

24 C3'-focused hybrids of aryl/penta-1,4-dien-3-one/amine (APDA) were designed and synthesized. Of these hybrids, 2 n demonstrated improved antiproliferative effects on HER2-positive breast cancer cells (SKBr3 and BT474) and triple-negative breast cancer (TNBC) cells (MDA-MB-231 and MDA-MB-468) with IC