Solid-State Emissive Triarylborane-Based [2.2]Paracyclophanes Displaying Circularly Polarized Luminescence and Thermally Activated Delayed Fluorescence.

New types of [2.2]paracyclophane derivatives, g-BNMe2-Cp and m-BNMe2-Cp, in which electron-donating NMe2 and the electron-accepting BMes2 are introduced at the pseudo -gem and pseudo -meta positions, were designed and synthesized. The efficient through-space charge transfer enables the intense fluorescence with thermally activated delayed fluorescence characteristics. The quantum yields are up to 0.72 and 0.39 in cyclohexane. In addition, no significant fluorescence quenching was observed in the solid state with fluorescence quantum yields of powder up to 0.53 and 0.33. Moreover, the enantiomerically pure forms of g-BNMe2-Cp exhibit strong CPL signals with glum up to 4.24 × 10-3.

Progress in copper-catalyzed trifluoromethylation.

The introduction of trifluoromethyl groups into organic molecules has attracted great attention in the past five years. In this review, we describe the recent efforts in the development of trifluoromethylation via copper catalysis using nucleophilic, electrophilic or radical trifluoromethylation reagents.

Synthesis and multidrug resistance reversal activity of dihydroptychantol A and its novel derivatives.

The macrocyclic bisbibenzyl dihydroptychantol A (DHA), previously isolated from Asterella angusta, was synthesized and showed significant multidrug resistance (MDR) reverting activity in chemoresistant cancer cells. In an attempt to discover more potent MDR reversal agents for efficient cancer chemotherapy, DHA derivatives with thiazole rings (19-22) were synthesized, and their cytotoxicities and MDR reversal activities were evaluated in adriamycin-resistant K562/A02, vincristine-resistant KB/VCR and in their parental cells by MTT assays. In response to treatment with each compound, the K562 cell line was the most sensitive, and the vincristine-resistant KB/VCR cell line was the most resistant. Marked decreases in K562 and K562/A02 cell viability were detectable after treatment with the synthesized derivatives of DHA, while less inhibitory effects on cell growth were observed in chemical-resistant KB/VCR and KB cells. Moreover, among the tested compounds, the intermediate 17 and the analogues 19, 20, and 21 showed potent MDR reversal activities and increased vincristine cytotoxicity in KB/VCR cells, with the reversal fold ranges from 10.54 to 13.81 (10microM), which is 3.2-4.3-fold stronger than the natural product DHA.

Synthesis of 4/5-deoxy-4/5-nucleobase derivatives of 3-O-methyl-D-chiro-inositol as potential antiviral agents.

Using D-pinitol (= 3-O-methyl-D-chiro-inositol) as starting material, a concise synthesis of 4/5-deoxy-4/5-nucleobase derivatives 11-19 has been achieved. The key intermediate 9 was obtained in good yield via an epoxidation from mono-methanesulfonate of D-pinitol. The process of opening of the epoxide ring in 9 by nucleobases appeared to be regioselective in presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). All the synthesized carbocyclic nucleosides were assayed against several viruses and tumors such as HIV-1, HSV-1, and HSV-2, and lung and bladder cancer. However, only compounds 14b, 14a, 16a, 16b, and 19 showed mild inhibitory effect against human lung cancer cell lines (PG) with IC50 values ranging from 50 to 100 microM, and the other compounds did not exhibit any significant antiviral activity or cytotoxicity even at concentrations up to 200 microM.