Total synthesis of an isoflavone <i>C</i>-glycoside: 6-tert-butylpuerarin

<p>The first total synthesis of an isoflavone <i>C</i>-glycoside (6-<i>tert</i>-butylpuerarin) using commercially available 4,6-di-<i>tert</i>-butylbenzene-1,3-diol as starting material was achieved in five steps with an overall yield of 2.8%. The key intermediate <b>4</b> was obtained by de-<i>tert</i>-butylation of <b>2</b> with trifluoroacetic acid and Friedel-Crafts acetylation of 2-<i>C</i>-β-D-glucopyranoside <b>3</b>. Condensation of <b>4</b> with 4-(benzyloxy)benzaldehyde resulted in the formation of <i>C</i>-glucosylchalcone <b>5</b>, which was cyclized by oxidative rearrangement using (diacetoxyiodo)benzene (DIB) and p-toluenesulfonic acid to obtain the target molecule <b>6</b>. This environmentally friendly and concise synthetic pathway should be applicable to the large-scale synthesis of various isoflavone <i>C</i>-glycosides.</p

Strontium-Incorporated Carbon Nitride Nanosheets Modulate Intracellular Tension for Reinforced Bone Regeneration

Strontium-containing agents have been demonstrated to elicit both bone anabolic and antiosteoporotic effects, showing great potential for the treatment of bone loss. However, an increased incidence of strontium-induced side effects restricts their clinical applications. Herein, oxidized carbon nitride nanosheets (CN) are delicately used to incorporate Sr2+ for the first time to achieve high osteogenic efficacy. The lamellar structure and enriched nitrogen species of CN provide them with a high surface area-to-volume ratio and abundant anchoring sites for Sr2+ incorporation. Importantly, Sr2+-incorporated CN (CNS) could synergistically promote osteoblast differentiation and bone regeneration at a single, very low Sr2+ dose. Mechanically, CNS could activate the FAK/RhoA signaling pathway to modulate the intracellular tension that stimulates osteoblasts differentiation. The present study will provide a new paradigm to enhance the efficacy of osteogenic metal ions by using lamellar nanocarriers