Stimulator of interferon genes (STING) is an endoplasmic reticulum-localized adaptor protein (STING receptor) that has been shown to be activated by binding to natural cyclic dinucleotide (CDN) ligands and plays a vital role in innate immune sensing of exogenous or endogenous DNA, which then induces type I interferons and other cytokines. In this paper, we described a series of amidobenzimidazole STING agonists with high potency for the STING receptor and presented the relevant structure–activity relationships (SARs). The relative potencies of compounds 16g, 24b, and 24e were measured by a STING competition binding assay. A more thorough study of the effect on the STING signaling pathway demonstrated that three compounds, 16g, 24b, and 24e, significantly increased the protein levels and mRNA levels of IFN-β, CXCL10, and IL-6, and 24b as a representative compound effectively triggered the phosphorylation of STING, TBK1, and IRF3 in both human peripheral blood mononuclear cells (hPBMCs) and WT THP-1 cells. In addition, compound 24b demonstrated impressive antitumor efficacy in mice with established syngeneic colon tumors by intravenous administration. Furthermore, the pharmacokinetic profile of compound 24b was fully evaluated.

An efficient one-pot synthesis of O-heterocycles or aryl ketones has been achieved using Et3SiH in the presence of InCl3 via a sequential ionic hydrogenation reaction by switching the solvent. This methodology can be used to construct C–O bonds and to prepare conjugate reduction products, including chromans, tetrahydrofurans, tetrahydropyrans, dihydroisobenzofurans, dihydrochalcones, and 1,4-diones in a facile manner. In addition, a novel plausible mechanism involving a conjugate reduction and a tandem reductive cyclization was verified by experimental investigations.

An efficient and facile method has been developed for the diversity-oriented synthesis of heterocycles. Hexahydrophenoxazines, tetrahydroquinolines, indolines, hexahydrocarbazoles, and lactones were conducted via Al(OTf)-promoted cascade cyclization and ionic hydrogenation. Furthermore, this protocol was utilized to smoothly prepare piracetam and its key intermediate as well.

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Sphingosine-1-phosphate receptor 1 (S1P1R), a member of the G protein-coupled receptor (GPCR) family, is an attractive protein target for the treatment of autoimmune diseases, and a diverse array of S1P1R agonists have been developed. Rational drug design based on S1P1R remains challenging due to the limited information available on the binding mode between S1P1R and its agonists. In this work, the active-like state of S1P1R was modeled via Gaussian accelerated molecular dynamics (GaMD) based on its inactive form, which was further validated by docking studies with two representative S1P1R agonists. Moreover, with the usage of the induced active-like state, the binding mode between S1P1R and its agonists was studied through molecular dynamics simulations and MM-GBSA calculations. The results of those studies indicated that four groups of binding site residues were the major contributors to the ligand and receptor interactions. In addition, this model was verified by five chemically similar compounds synthesized in-house and 1145 known S1P1R agonists collected from the BindingDB database. The elucidation of the key binding characteristics will further complete the cognition of S1P1R, which can guide the rational design of novel S1P1R agonists.