Koichiro Mukoyoshi

Synthesis and Evaluation of 1H-Pyrrolo[2,3-b]pyridine Derivatives as Novel Immunomodulators Targeting Janus Kinase 3

Janus kinases (JAKs) have been known to play crucial roles in modulating a number of inflammatory and immune mediators. Here, we describe a series of 1H-pyrrolo[2,3-b]pyridine derivatives as novel immunomodulators targeting JAK3 for use in treating immune diseases such as organ transplantation. In the chemical modification of compound 6, the introduction of a carbamoyl group to the C5-position and substitution of a cyclohexylamino group at the C4-position of the 1H-pyrrolo[2,3-b]pyridine ring led to a large increase in JAK3 inhibitory activity. Compound 14c was identified as a potent, moderately selective JAK3 inhibitor, and the immunomodulating effect of 14c on interleukin-2-stimulated T cell proliferation was shown. Docking calculations and WaterMap analysis of the 1H-pyrrolo[2,3-b]pyridine-5-carboxamide derivatives were conducted to confirm the substituent effects on JAK3 inhibitory activity.

Optimization of 2,4-diamino-5-fluoropyrimidine derivatives as protein kinase C theta inhibitors with mitigated time-dependent drug-drug interactions and P-gp liability.

Protein kinase C theta (PKCθ) plays a critical role in T cell signaling and has therapeutic potential for T cell-mediated diseases such as transplant rejection and rheumatoid arthritis. Here, a series of 2,4-diamino-5-fluoropyrimidine derivatives were prepared and evaluated for their inhibition of PKCθ. Of these compounds, 14f was found to exhibit potent PKCθ inhibitory activity and significantly weak CYP3A4 time-dependent inhibition (TDI) and P-glycoprotein (P-gp) liability.

Synthesis and evaluation of novel 1H-pyrrolo[2,3-b]pyridine-5-carboxamide derivatives as potent and orally efficacious immunomodulators targeting JAK3.

Janus kinases (JAKs) regulate various inflammatory and immune responses and are targets for the treatment of inflammatory and immune diseases. As a novel class of immunomodulators targeting JAK3, 1H-pyrrolo[2,3-b]pyridine-5-carboxamide derivatives are promising candidates for treating such diseases. In chemical modification of lead compound 2, the substitution of a cycloalkyl ring for an N-cyanopyridylpiperidine in C4-position was effective for increasing JAK3 inhibitory activity. In addition, modulation of physical properties such as molecular lipophilicity and basicity was important for reducing human ether-a-go-go-related gene (hERG) inhibitory activity. Our optimization study gave compound 31, which exhibited potent JAK3 inhibitory activity as well as weak hERG inhibitory activity. In cellular assay, 31 exhibited potent immunomodulating effect on IL-2-stimulated T cell proliferation. In a pharmacokinetic study, good metabolic stability and oral bioavailability of 31 were achieved in rats, dogs, and monkeys. Further, 31 prolonged graft survival in an in vivo rat heterotopic cardiac transplant model.

Discovery and biological evaluation of novel pyrazolopyridine derivatives as potent and orally available PI3Kδ inhibitors

Phosphatidylinositol-3-kinase (PI3K)δ inhibition is one of the most attractive approaches to the treatment of autoimmune diseases and leukocyte malignancies. Through the exploration of pyrazolopyridine derivatives as potential PI3Kδ inhibitors, compound 12a was identified as a potent PI3Kδ inhibitor but suffered from poor oral exposure in mice. With a modified amide linkage group, compound 15a was developed as an orally available PI3Kδ inhibitor with reduced selectivity against other PI3Ks. To improve the trade-off between selectivity and PK profile, structure-activity relationship (SAR) studies of terminal substituents on the pyrolidine ring were conducted. As a result, we developed potent PI3Kδ inhibitors with good oral availability. In particular, the representative compound 15j showed excellent selectivity for PI3Kδ over other PI3Ks with good oral exposure in mice.