Construction of 1,3,4-oxadiazolines bearing CF3-quaternary centers via amino-assisted [3 + 2] cycloadditions.

An amino-assisted [3 + 2] cycloaddition strategy of nitrile imines with o-aminotrifluoroacetophenones has been explored, thus providing functionalized 1,3,4-oxadiazolines bearing CF3-quaternary centers in good to excellent yields in the presence of K2CO3 under mild conditions. The amino groups located at the ortho-position of trifluoroacetophenone might play a crucial role in the present cyclization. The MTT assay shows that the 1,3,4-oxadiazoline derivatives could be potential candidates for the treatment of head and neck cancers.

Novel 3,4-dihydroquinolin-2(1H)-one derivatives as dual inhibitor targeting AKR1B1/ROS for treatment of diabetic complications: Design, synthesis and biological evaluation.

AKR1B1 (Aldose reductase) has been used as therapeutic intervention target for treatment of diabetic complications over 50 years, and more recently for inflammation and cancer. However, most developed small molecule inhibitors have the defect of low bioactivity. To address this limitation, novel series of 3,4-dihydroquinolin-2(1H)-one derivatives as dual inhibitor targeting AKR1B1/ROS (Reactive Oxygen Species) were designed and synthesized. Most of these derivatives were found to be potent and selective against AKR1B1, and compound 8a was the most active with an IC50 value of 0.035 µM. Moreover, some prepared derivatives showed strong anti-ROS activity, and among them the phenolic 3,5-dihydroxyl compound 8b was proved to be the most potent, even comparable to that of the well-known antioxidant Trolox at a concentration of 100 µM. Thus the results suggested a success in the construction of potent dual inhibitor for the therapeutic intervention target of AKR1B1/ROS.

GSH responsive nanomedicines self-assembled from small molecule prodrug alleviate the toxicity of cardiac glycosides as potent cancer drugs.

Cardiac glycosides (CGs) have been used to treat cancer for hundreds of years. However, the narrow therapeutic window and system toxicity have hindered their wide clinical applications. Herein, the small molecule prodrug strategy and nanotechnology were integrated into one drug delivery system with enhanced therapeutic effect. Using periplocymarin (PPM) as a target agent, we designed a novel redox-responsive prodrug conjugated with linoleic acid (PPM-ss-LA), which was capable of self-assembling independent of exogenous excipients. This prodrug could co-assemble with DSPE2k to form PEGylated prodrug nanoparticles (PPM-ss-LA/DSPE2k-NPs) with enhanced colloidal stability and blood circulation. Compared with free PPM, PPM-ss-LA/DSPE2k-NPs retained high anti-proliferative activity and showed increased cell uptake and therapeutic efficacy. Furthermore, the PPM-ss-LA/DSPE2k-NPs acquired a greatly enhancement of 50% lethal dose (LD50) in mice and reduced system toxicity compared with the free drug. Overall, the on-demand release of nanoprodrug delivery system could improve the therapeutic window and anticancer efficacy of CGs.