No abstract

Using gem-difluoromethylene alkynes as effectors, unprecedented diverse CÀHa ctivation/[4+ +2] annulations of simple benzoica cids are reported. The chemodivergent reaction outcomes are well-tuned by Rh/Ir-catalyzed system; in the Rh III catalysis,3-alkenyl-1H-isochromen-1-one and 3,4dialkylideneisochroman-1-one skeletons are afforded in asolvent-dependent manner whereas difluoromethylene-substituted 1H-isochromen-1-ones are generated under the Ir III-catalyzed system. Mechanistic studies revealed that unusually double b-F eliminations and fluorine effect-induced regioselective reductive elimination are independently involved to enable distinct reaction modes for divergent product formations.B esides,s ynthetic application in both the derivatization of obtained diene products and the on-DNAsynthesis of DNAtagged difluorinated isocoumarin have been demonstrated, which manifested great potential for synthetic utility of the developed protocols.

Estrogen deficiency induces cardiac dysfunction and increases the risk of cardiovascular disease in postmenopausal women and in those who underwent bilateral oophorectomy. Previous evidence suggests that puerarin, a phytoestrogen, exerts beneficial effects on cardiac function in patients with cardiac hypertrophy. In this study, we investigated whether puerarin could prevent cardiac hypertrophy and remodeling in ovariectomized, aortic-banded rats. Female SD rats subjected to bilateral ovariectomy (OVX) plus abdominal aortic constriction (AAC). The rats were treated with puerarin (50 mg•kg −1 •d −1 , ip) for 8 weeks. Then echocardiography was assessed, and the rats were sacrificed, their heart tissues were extracted and allocated for further experiments. We showed that puerarin administration significantly attenuated cardiac hypertrophy and remodeling in AAC-treated OVX rats, which could be attributed to activation of PPARα/PPARγ coactivator-1 (PGC-1) pathway. Puerarin administration significantly increased the expression of estrogen-related receptor α, nuclear respiratory factor 1, and mitochondrial transcription factor A in hearts. Moreover, puerarin administration regulated the expression of metabolic genes in AAC-treated OVX rats. Hypertrophic changes could be induced in neonatal rat cardiomyocytes (NRCM) in vitro by treatment with angiotensin II (Ang II, 1 μM), which was attenuated by cotreatemnt with puerarin (100 μM). We further showed that puerarin decreased Ang II-induced accumulation of non-esterified fatty acids (NEFAs) and deletion of ATP, attenuated the Ang II-induced dissipation of the mitochondrial membrane potential, and improved the mitochondrial dysfunction in NRCM. Furthermore, addition of PPARα antagonist GW6471 (10 μM) partially abolished the anti-hypertrophic effects and metabolic effects of puerarin in NRCM. In conclusion, puerarin prevents cardiac hypertrophy in AAC-treated OVX rats through activation of PPARα/PGC-1 pathway and regulation of energy metabolism remodeling. This may provide a new approach to prevent the development of heart failure in postmenopausal women.