Hiroshi Nagata

Novel 7H-pyrrolo[2,3-d]pyrimidine derivatives as potent and orally active STAT6 inhibitors.

Signal transducers and activators of transcription 6 (STAT6) is an important transcription factor in interleukin (IL)-4 signaling pathway and a key regulator of the type 2 helper T (Th2) cell immune response. Therefore, STAT6 may be an excellent therapeutic target for allergic conditions, including asthma and atopic diseases. Previously, we reported 4-aminopyrimidine-5-carboxamide derivatives as STAT6 inhibitors. To search for novel STAT6 inhibitors, we synthesized fused bicyclic pyrimidine derivatives and identified a 7H-pyrrolo[2,3-d]pyrimidine derivative as a STAT6 inhibitor. Optimization of the pyrrolopyrimidine derivatives led to identification of 2-[4-(4-{[7-(3,5-difluorobenzyl)-7H-pyrrolo[2,3-d]pyrimidin-2-yl]amino}phenyl)piperazin-1-yl]acetamide (24, AS1810722) which showed potent STAT6 inhibition and a good CYP3A4 inhibition profile. Compound 24 also inhibited in vitro Th2 differentiation without affecting type 1 helper T (Th1) cell differentiation and eosinophil infiltration in an antigen-induced mouse asthmatic model after oral administration.

Identification of 4-benzylamino-2-[(4-morpholin-4-ylphenyl)amino]pyrimidine-5-carboxamide derivatives as potent and orally bioavailable STAT6 inhibitors

Signal transducers and activators of transcription 6 (STAT6) is a key regulator of the type 2 helper T (Th2) cell immune response and a potential therapeutic target for allergic diseases such as asthma and atopic diseases. To search for potent and orally bioavailable STAT6 inhibitors, we synthesized a series of 4-benzylaminopyrimidine-5-carboxamide derivatives and evaluated their STAT6 inhibitory activities. Among these compounds, 2-[(4-morpholin-4-ylphenyl)amino]-4-[(2,3,6-trifluorobenzyl)amino]pyrimidine-5-carboxamide (25y, YM-341619, AS1617612) showed potent STAT6 inhibition with an IC(50) of 0.70nM, and also inhibited Th2 differentiation in mouse spleen T cells induced by interleukin (IL)-4 with an IC(50) of 0.28 nM without affecting type 1 helper T (Th1) cell differentiation induced by IL-12. In addition, compound 25y showed an oral bioavailability of 25% in mouse.

Discovery of novel and potent CRTH2 antagonists.

High throughput screening of our chemical library for CRTH2 antagonists provided a lead compound 1a. Initial optimization of the lead led to the discovery of a novel, potent and orally bioavailable CRTH2 antagonist 17.

Novel quinuclidinyl heteroarylcarbamate derivatives as muscarinic receptor antagonists.

Herein, we describe the synthesis and pharmacological profiles of novel quinuclidinyl heteroarylcarbamate derivatives. Among them, the quinuclidin-4-yl thiazolylcarbamate derivative ASP9133 was identified as a promising long-acting muscarinic antagonist (LAMA) showing more selective inhibition of bronchoconstriction against salivation and more rapid onset of action in a rat model than tiotropium bromide.