Synthesis and evaluation of 3-amino-6-aryl-pyridazines as selective CB2 agonists for the treatment of inflammatory pain

A series of 3-amino-6-aryl-pyridazines have been identified as CB2 agonists with high efficacy and selectivity against the CB1 receptor. Details of the investigation of structure–activity relationships (SAR) are disclosed, which led to the identification of pyridazine analogue 35, a compound with high potency in an in vivo model of inflammatory pain.