We present the development of new affinity probes for protein labeling based on an epoxide reactive group. Systematic screening revealed that an epoxide functionality possesses the special combination of stability and reactivity which renders it stable toward proteins in solution but reactive on the protein surface outside the active site (proximity-induced reactivity). Highly efficient and selective labeling of purified HCA II (human carbonic anhydrase II) was achieved. For instance, 2 equiv of epoxide probe 9 was sufficient for nearly quantitative labeling of HCA II (>90% yield, 20 h reaction time). MS analysis of the labeled protein revealed that 1 equiv of the probe was attached and that labeling occurred at a single residue (His 64) outside the active site. Importantly, epoxide probe 9 selectively labeled HCA II both in simple protein mixtures and in cellular extracts. In addition to the chemical insight and its relevance to many epoxide-containing natural products, this study generated a promising lead in the development of new affinity probes for protein labeling.

Syntheses and structure-activity relationships (SAR) of nonsteroidal glucocorticoid receptor (GR) agonists are described. These compounds contain azaindole moieties as A-ring mimetics and display various degrees of in vitro dissociation between gene transrepression and transactivation. Collagen induced arthritis studies in mouse have demonstrated that in vitro dissociated compounds (R)-16 and (R)-37 have steroid-like anti-inflammatory properties with improved metabolic side effect profiles, such as a reduced increase in body fat and serum insulin levels, compared to steroids.

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Synthesis and structure-activity relationship (SAR) of a series of nonsteroidal glucocorticoid receptor (GR) agonists are described. These compounds contain "diazaindole" moieties and display different transcriptional regulatory profiles in vitro and are considered "dissociated" between gene transrepression and transactivation. The lead optimization effort described in this article focused in particular on limiting the transactivation of genes which result in bone side effects and these were assessed in vitro in MG-63 osteosarcoma cells, leading to the identification of (R)-18 and (R)-21. These compounds maintained anti-inflammatory activity in vivo in collagen induced arthritis studies in mouse but had reduced effects on bone relevant parameters compared to the widely used synthetic glucocorticoid prednisolone 2 in vivo. To our knowledge, we are the first to report on selective glucocorticoid ligands with reduced bone loss in a preclinical in vivo model.