Efficient synthesis of polymethoxyselenoflavones via regioselective direct C-H arylation of selenochromones

Synthesis of Fluoromethylated Chromones and Their Heteroatom Analogues via Sodium Fluoromethanesulfinate-Enabled Direct Fluoromethylation

An array of biologically interesting tri/difluoromethylated chromones and their heteroatom analogues were conveniently synthesized from the reaction of chromones and their heteroatom analogues with CF3SO2Na or HCF2SO2Na in the presence of tert-butyl hydroperoxide under mild conditions. A mechanistic pathway involving the generation of the electrophilic tri/difluoromethyl radical, followed with the radical substitution of chromones and their heteroatom analogues, was postulated.

Silver-Mediated Intermolecular [2 + 2 + 1] Cyclization of Terminal Alkynones with Elemental Selenium: Regioselective Synthesis of 2,4- or 3,4-Dicarbonylselenophenes

An efficient and atom-economical silver-mediated [2 + 2 + 1] cyclization protocol for the selective synthesis of 2,4- or 3,4-dicarbonylselenophenes has been developed. Readily accessible substrates, commercially available elemental selenium, and good functional group tolerance make this procedure attractive for the selective synthesis of dicarbonylselenophenes. Preliminary mechanistic investigations indicated that silver acetylene species are possible intermediates for the formation of 3,4-dicarbonylselenophenes.

Access to 12-Membered Cyclic ortho,meta-Diarylheptanoids: Total Synthesis of Actinidione via Isomyricanone

We describe herein the first access to 12-membered cyclic[7,0]ortho,meta-diarylheptanoids. The key features of the synthesis include both a Suzuki-Miyaura coupling and a ring closing metathesis. Actinidione, a promising natural product, along with a bioactive tetracyclic derivative were obtained in 14 steps for the first time from cheap commercially available substrates with an overall yield of 18-21%. Our modus operandi complies with the principles of the synthesis ideality by using notably strategic reactions.

Synthesis of Selenopyrano[2,3-c]pyrazol-4(1H)-ones and Their C–H Activation

We disclose the synthesis of selenopyrano[2,3-c]pyrazol-4(1H)-ones and their aryl derivatives for the first time by using selenopyran ring formation via an in situ-generated selenide that reacts directly with α-halo-β-ynone-bearing substituted pyrazoles to provide the corresponding selenopyrano[2,3-c]pyrazol-4(1H)-ones. Subsequent direct C–H arylation of the latter compounds effected by palladium-catalyzed Heck reactions permits the incorporation of arene substituents onto the selenopyrano[2,3-c]pyrazol-4(1H)-ones scaffolds with moderate to good yields, and might be useful for biological screenings.

A Cascade Reaction of Michael Addition and Truce-Smiles Rearrangement to Synthesize Trisubstituted 4-Quinolone Derivatives

A novel transition-metal-free cascade reaction to synthesize 4-quinolone derivatives has been demonstrated. Michael addition and Truce-Smiles rearrangement are included in this protocol, providing a broad scope of 4-quinolones in moderate-to-excellent yields. This work serves as an example of the use of sulfonamides through Truce-Smiles rearrangement to build heterocyclic compounds under mild conditions.

Polymethoxyselenoflavones exert anti-obesity effects through activation of lipolysis and brown adipocyte metabolism

BACKGROUND/OBJECTIVES

Polymethoxyselenoflavone (PMSF) is a compound that substitutes the oxygen atom in a flavonoid with selenium. This study aimed to investigate the effects of PMSFs on lipid metabolism in adipocytes and their anti-obesity potential.

SUBJECTS/METHODS

To test lipolytic and thermogenic effects of the compounds in vitro, adipocytes differentiated from immortalized pre-brown adipocyte progenitors and pre-white adipocyte cell lines were treated with 19 PMSFs. The expression levels of brown adipocyte markers and genes related to mitochondrial metabolism were analyzed by qPCR and western blot. In vivo anti-obesity effect was investigated using diet-induced obesity mouse models and adipocyte-specific ATGL knockout mice.

RESULTS

The qPCR analysis identified 2-(3,4-dimethoxyphenyl)-4H-selenochromen-4-one (DMPSC) as the most potent brown adipogenic candidate among the 19 compounds tested in this study. DMPSC treatment significantly increased the mitochondrial content and oxidative metabolism in adipocytes in vitro. Mechanistically, DMPSC treatment increased lipolysis through activation of PKA downstream signaling. Consistently, the in vivo treatment of DMPSC increased energy consumption, reduced body weight, and improved glucose tolerance in mice fed with high-fat diets. Moreover, DMPSC treatment increased brown adipocyte marker expression and mitochondrial content in adipose tissue of mice. The anti-obesity effects were absent in adipocyte-specific ATGL knockout mice, indicating that the DMPSC effect is mediated by cytosolic lipase-dependent mechanisms.

CONCLUSIONS

Collectively, our results indicated that DMPSC exerted anti-obesity effects partially through the PKA signaling-mediated activation of lipolysis and brown adipose tissue metabolism.

Chemoselective α-Methylenation of Aromatic Ketones Using the NaAuCl4/Selectfluor/DMSO System

Gold-catalyzed chemoselective α-methylenation of aromatic ketones was developed through the use of Selectfluor as a methylenating agent. A variety of useful 1,2-disubstituted propenone derivatives can be prepared in good yields via the present protocol. This reaction features a simple operation, good functional group tolerance, and broad scope of substrates.