The medicinal chemistry community has directed considerable efforts toward the discovery of selective inhibitors of interleukin-2 inducible T-cell kinase (ITK), given its role in T-cell signaling downstream of the T-cell receptor (TCR) and the implications of this target for inflammatory disorders such as asthma. We have previously disclosed a structure- and property-guided lead optimization effort which resulted in the discovery of a new series of tetrahydroindazole-containing selective ITK inhibitors. Herein we disclose further optimization of this series that resulted in further potency improvements, reduced off-target receptor binding liabilities, and reduced cytotoxicity. Specifically, we have identified a correlation between the basicity of solubilizing elements in the ITK inhibitors and off-target antiproliferative effects, which was exploited to reduce cytotoxicity while maintaining kinase selectivity. Optimized analogues were shown to reduce IL-2 and IL-13 production in vivo following oral or intraperitoneal dosing in mice.

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Transient receptor potential ankyrin 1 (TRPA1) is a non-selective cation channel expressed in sensory neurons where it functions as an irritant sensor for a plethora of electrophilic compounds and is implicated in pain, itch, and respiratory disease. To study its function in various disease contexts, we sought to identify novel, potent, and selective small-molecule TRPA1 antagonists. Herein we describe the evolution of an N-isopropylglycine sulfonamide lead (1) to a novel and potent (4 R,5 S)-4-fluoro-5-methylproline sulfonamide series of inhibitors. Molecular modeling was utilized to derive low-energy three-dimensional conformations to guide ligand design. This effort led to compound 20, which possessed a balanced combination of potency and metabolic stability but poor solubility that ultimately limited in vivo exposure. To improve solubility and in vivo exposure, we developed methylene phosphate prodrug 22, which demonstrated superior oral exposure and robust in vivo target engagement in a rat model of AITC-induced pain.

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Neural progenitor cells (NPCs) are sequentially specified into neurons and glia during the development of central nervous system. WNT/β‐catenin signaling is known to regulate the balance between the proliferation and differentiation of NPCs during neurogenesis. However, the function of WNT/β‐catenin signaling during gliogenesis remains poorly defined. Here, we report that activation of WNT/β‐catenin signaling disrupts astrogliogenesis in the developing spinal cord. Conversely, inhibition of WNT/β‐catenin signaling leads to precocious astrogliogenesis. Further analysis reveals that activation of WNT/β‐catenin pathway results in a dramatic increase of neurogenin 2 (Ngn2) expression in transgenic mice, and knockdown of Ngn2 expression in neural precursor cells can reverse the inhibitory effect of WNT/β‐catenin on astrocytic differentiation. Moreover, Ngn2 can directly bind to the promoters of several astrocyte specific genes and suppress their expression independent of STATs activity. Together, our studies provide the first in vivo evidence that WNT/β‐catenin signaling inhibits early astrogliogenesis via an Ngn2‐dependent transcriptional repression mechanism.

A cyclometalation reaction involving C-F bond activation at a cobalt(i) center with an aldazine-N atom as anchoring group affords ortho-chelated cobalt(iii) complexes containing a [C-Co-F] fragment [CoFMe(PMe(3))(2){(C(6)H(3)F-ortho)CH[double bond, length as m-dash]N-R}] 5-8. Under similar reaction conditions π-coordinated cobalt(0) complexes [Co(PMe(3))(3)((C(6)H(3)F-ortho)CH[double bond, length as m-dash]N-R)] 12-14 were formed when [Co(PMe(3))(4)], instead of [CoMe(PMe(3))(4)], was applied. C-F bond activation did not occur. Carbonylation of complexes 6-8 delivered novel organic fluorides 15-17. A proposed formation mechanism of the novel organic fluorides with demetallation and carbonylation of complexes 6-8 by CO is discussed with experimental support. As important intermediates, an acetyl cobalt complex, [CoFMeC[double bond, length as m-dash]O(PMe(3))(2){(C(6)H(3)F-ortho)CH[double bond, length as m-dash]N-R}] 20, and a 19-electron cobalt(0) complex, Co(CO)(3)(PMe(3))(2)21, were structurally characterized. The crystal and molecular structures of complexes 5, 6, 8, 12, 20 and 21 were determined by X-ray diffraction.

C-F bond activation of ortho-fluorinated benzalimines 2,6-F(2)C(6)R1R2R3-CH=N-R (1-3) using the electron-rich complex Fe(PMe(3))(4) is reported. With the assistance of the imine group as the anchoring group, bis-chelated iron(II) complexes (C(6)FR1R2R3-CH=N-R)(2)Fe(PMe(3))(2) (4-6) were formed. The reaction of 2,6-difluorobenzylidenenaphthalen-1-amine 2,6-F(2)C(6)H(3)-CH=N-C(10)H(7) (9) with Fe(PMe(3))(4) affords [CNC]-pincer iron(II) complex (C(6)H(3)F-CH=N-C(10)H(6))Fe(PMe(3))(3) (10) through both C-F and C-H bond activation and π-(C=N) coordinate iron(0) complex (C(6)H(3)F-CH=N-C(10)H(7))(2)Fe(PMe(3))(2) (11) with C,C-coupling, while a similar reaction with perfluorobenzylidenenaphthalen-1-amine C(6)F(5)-CH=N-C(10)H(7) (14) gave rise to only [CNC]-pincer iron(II) complex (C(6)F(4)-CH=N-C(10)H(6))Fe(PMe(3))(3) (15). The proposed formation mechanisms of these complexes are discussed. The structures of complexes 5, 6, 10 and 11 were confirmed by X-ray single crystal diffraction.