In recent years, the selective inhibition of FKBP51 has emerged as a possible treatment for chronic pain, obesityinduced diabetes, or depression. All currently known advanced FKBP51-selective inhibitors, including the widely used SAFit2, contain a cyclohexyl residue as a key motif for enabling selectivity over the closest homologue and anti-target FKBP52. During a structure-based SAR exploration, we surprisingly discovered thiophenes as highly efficient cyclohexyl replacement moieties that retain the strong selectivity of SAFit-type inhibitors for FKBP51 over FKBP52. Cocrystal structures revealed that the thiophenecontaining moieties enable selectivity by stabilizing a flipped-out conformation of Phe 67 of FKBP51. Our best compound, 19b, potently binds to FKBP51 biochemically as well as in mammalian cells, desensitize TRPV1 in primary sensory neurons, and has an acceptable PK profile in mice, suggesting its use as a novel tool compound for studying FKBP51 in animal models of neuropathic pain.

A new practical, catalytic, and highly stereoselective method for directly accessing 1,1-α,α′-linked 2-deoxy trehalose analogues via AuCl 3 -catalyzed dehydrative glycosylation using hemiacetal glycosyl donors and acceptors is described. The method relies on the chemoselective Brønsted acid-type activation of tribenzylated 2-deoxy hemiacetals in the presence of other less reactive hemiacetals.

In recent years the selective inhibition of FKBP51 has emerged as a possible treatment for chronic pain, obesity-induced diabetes, or depression. All currently known advanced FKBP51-selective inhibitors, including the widely used SAFit2, contain a cyclohexyl residue as a key motif for enabling selectivity over the closest homolog and anti-target FKBP52. During a structure-based SAR exploration we surprisingly discovered thiophenes as highly efficient cyclohexyl replacement moieties that retain the strong selectivity of SAFit-type inhibitors for FKBP51 over FKBP52. Cocrystal structures revealed that the thiophene-containing moieties enable selectivity by stabilizing a flipped-out conformation of Phe67 of FKBP51. Our best compound 19b potently binds to FKBP51 biochemically as well as in mammalian cells, desensitize TRPV1 in primary sensory neurons, and has an acceptable PK profile in mice, suggesting its use as novel tool compound for studying FKBP51 in animal models of neuropathic pain.

No abstract