Tuning the Reactivity of Alkoxyl Radicals from Cyclization to 1,2-Silyl Transfer: Stereoselective Synthesis of β-Substituted Cycloalcohols.

Herein, we report a radical strategy for diastereoselective construction of β-substituted cyclopentanols and cyclobutanols. The success of the reaction is attributed to the favorable radical 1,2-silyl transfer over the cyclization of alkoxy radicals to the olefins. The reaction shows broad substrate scope and wide functional-group tolerance.

Synthesis of Stereodefined Trisubstituted Alkenyl Silanes Enabled by Borane Catalysis and Nickel Catalysis.

Regioselective and stereoselective synthesis of trisubstituted alkenyl silanes via hydrosilylation is challenging. Herein, we report the first β--selective addition of silanes to thioalkynes with B(CF) as the catalyst. The reaction shows broad substrate scope.

Synthesis of trifluoroalkyl or difluoroalkyl phenanthridine derivatives via cascade reaction using an intramolecular cyano group as a radical acceptor under photoredox catalysis.

In the presence of Ru(phen)Cl or fac-Ir(ppy) under visible-light irradiation, the addition of fluorinated radicals to N-arylacrylamides followed by an intramolecular cyano group insertion cascade cyclization process produced trifluoroalkyl or difluoroalkyl phenanthridine derivatives in moderate to good yields. Three easily available fluoroalkylated reagents CFSOCl, BrCFCOEt and BrCFPO(OEt) were used as the sources of fluorinated radicals.

Design, synthesis and evaluation of the multidrug resistance-reversing activity of pyridine acid esters of podophyllotoxin in human leukemia cells.

Multidrug resistance (MDR) is the main cause for chemotherapeutic failure in cancer treatment. To overcome MDR, a serious of pyridine acid esters of podophyllotoxin was synthesized and their antiproliferation activities were evaluated against two human chronic myeloid leukemia cell lines in vitro. Most of them exhibited potent growth inhibition with IC50 values in the nanomolar range as well as markedly reduced resistance factors.

Aromatic heterocyclic esters of podophyllotoxin exert anti-MDR activity in human leukemia K562/ADR cells via ROS/MAPK signaling pathways.

Currently, multi-drug resistance (MDR) to antineoplastic drugs is a major obstacle to successful treatment of carcinoma. Looking for novel agents with anti-MDR activity is an effectively way to overcome cancer drug resistance. Our previous study showed that podophyllotoxin derivative exhibited potent anti-proliferative effect and down-regulated the expression level of P-gp in K562/ADR cells, which probably was related with the MAPK pathways.

Synthesis and biological evaluation of a novel artesunate-podophyllotoxin conjugate as anticancer agent.

A novel conjugate of artesunate-podophyllotoxin was prepared and evaluated for its cytotoxicity against diverse normal and multidrug resistance human cancer cell lines by CCK-8 assay. The conjugate exhibited good cytotoxicity on all the cell lines with IC50 values of 0.453±0.

Effect of Sini San freeze-dried powder on sleep-waking cycle in insomnia rats.

Objective: To investigate the effects of the Sini San at different doses on each sleeping state [slow-wave sleep 1 (SWS 1), slow-wave sleep 2 (SWS2), rapid-eye-movement (REM), wakefulness (W)] in insomnia rats and to identify its mode of action for improving sleep.

Methods: The insomnia rats were randomly divided into a high-, medium- or low-dose group of Sini San (equal to crude drug 8.8, 4.