N-(Pyridin-2-yl)amides and 3-bromoimidazo[1,2-a]pyridines were synthesized respectively from abromoketones and 2-aminopyridine under different reaction conditions. N-(Pyridin-2-yl)amides were formed in toluene via C-C bond cleavage promoted by I 2 and TBHP and the reaction conditions were mild and metal-free. Whereas 3-bromoimidazopyridines were obtained in ethyl acetate via one-pot tandem cyclization/bromination when only TBHP was added, the cyclization to form imidazopyridines was promoted by the further bromination, no base was needed, and the versatile 3bromoimidazopyridines could be further transferred to other skeletons.Scheme 1 Recent methods for the construction of pyridyl-amides and halosubstituted imidazopyridines.34672 | RSC Adv., 2019,9,[34671][34672][34673][34674][34675][34676] This journal is Scheme 6 Proposed reaction mechanism.This journal is

A series of C-23 modified 23-hydroxybetulinic acid (HBA) derivatives were synthesized and evaluated for their antiproliferative activity against a panel of cancer cell lines (A2780, A375, B16, MCF-7 and HepG2). The biological screening results showed that most of the derivatives exhibited more potent antiproliferative activity than HBA, and compound 6e exhibited the most potent activity with IC50 values of 2.14 μM, 2.89 μM, and 3.97 μM against A2780, B16, and MCF-7 cells, respectively.Further anticancer mechanism studies revealed that compound 6e induced the generation of intracellular reactive oxygen species (ROS) and reduction of mitochondrial membrane potential (MMP) of B16 cells in a dose-dependent manner.Moreover, western blot analysis indicated that compound 6e downregulated the expression of anti-apoptotic protein Bcl-2 and upregulated the expression of proapoptotic protein Bax, activation of caspase 3 to induce cell apoptosis. Meanwhile, compound 6e significantly inhibited the phosphorylation of MEK, ERK, and Akt without affecting the expression of MEK, ERK, and Akt. Furthermore, the in vivo anti-tumor activity of 6e was validated (tumor inhibitory ratio of 68.4% at the dose of 30 mg/kg) in mice with B16 melanoma.

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