6-{4-[3-(R)-2-Methylpyrrolidin-1-yl) propoxy]-phenyl}-2H-pyridazin-3-one 6 (Irdabisant; CEP- 26401) was recently reported as a potent H3R antagonist with excellent drug-like properties and in vivo activity that advanced into clinical evaluation. A series of pyridone analogs of 6 ...