A general approach is presented for developing small molecule-based fluorogenic probes suitable for no-wash imaging of endogenous kinases in live cells. Probe 1, including a fluorophore–quencher system, was only “turned on” upon reacting with its target kinase Btk, and disclosed Btk's cellular location in live cells without any washing.

Highly substituted chiral hydantoins were readily synthesized from simple dipeptides in a single step under mild conditions. This reaction proceeded through the dual activation of an amide and a tert-butyloxycarbonyl (Boc) protecting group by Tf2O-pyridine. This method was successfully applied in the preparation of a variety of biologically active compounds, including drug analogs and natural products.

Bruton’s tyrosine kinase (Btk) is an attractive drug target for treating several B-cell lineage cancers. Ibrutinib is a first-in-class covalent irreversible Btk inhibitor and has demonstrated impressive effects in multiple clinical trials. Herein, we present a series of novel 2,5-diaminopyrimidine covalent irreversible inhibitors of Btk. Compared with ibrutinib, these inhibitors exhibited a different selectivity profile for the analyzed kinases as well as a dual-action mode of inhibition of both Btk activation and catalytic activity, which counteracts a negative regulation loop for Btk. Two compounds from this series, 31 and 38, showed potent antiproliferative activities toward multiple B-cell lymphoma cell lines, including germinal center B-cell-like diffuse large B cell lymphoma (GCB-DLBCL) cells. In addition, compound 31 significantly prevented tumor growth in a mouse xenograft model.

The immobilization of functional proteins onto solid supports using affinity tags is an attractive approach in recent development of protein microarray technologies. Among the commonly used fusion protein tags, glutathione S-transferase (GST) proteins have been indispensable tools for protein–protein interaction studies and have extensive applications in recombinant protein purification and reversible protein immobilization. Here, by utilizing pyrimidine-based small-molecule probes with a sulfonyl fluoride reactive group, we report a novel and general approach for site-selective immobilization of Schistosoma japonicum GST (sjGST) fusion proteins through irreversible and specific covalent modification of the tyrosine-111 residue of the sjGST tag. As demonstrated by sjGST-tagged eGFP and sjGST-tagged kinase activity assays, this immobilization approach offers the advantages of high immobilization efficiency and excellent retention of protein structure and activity.

Glyoxalase I (GLO-1) plays a critical role in the detoxification of 2-oxoaldehydes and is highly expressed in cancer cells. Through photo-affinity labelling and affinity pull-down approaches, a series of 2,4-diaminopyrimidine compounds were discovered to selectively bind to GLO-1 in cells. These compounds show potent inhibition of GLO-1 enzyme activity and prevent proliferation of cancer cells. The cell permeable and “clickable” photoaffinity probe L1-Bpyne presented here could be a valuable tool for profiling GLO-1 in live cells.

Polystyrene–polyamidoamine-supported gold nanoparticles were prepared using a reductant-directed formation strategy. The resulting catalysts exhibited excellent activities in the aerobic oxidation of benzyl alcohols and the homocoupling of phenylboronic acids under mild conditions and can be recycled at least 14 times without significant loss of activity.

Polystyrene–polyamidoamine-supported gold nanoparticles were prepared using a reductant-directed formation strategy. The resulting catalysts exhibited excellent activities in the aerobic oxidation of benzyl alcohols and the homocoupling of phenylboronic acids under mild conditions and can be recycled at least 14 times without significant loss of activity.

A general approach is presented for developing small molecule-based fluorogenic probes suitable for no-wash imaging of endogenous kinases in live cells. Probe 1, including a fluorophore–quencher system, was only “turned on” upon reacting with its target kinase Btk, and disclosed Btk's cellular location in live cells without any washing.