AM-1221
AM-1221 is a drug that acts as a potent and selective agonist for the cannabinoid receptor CB2, with a Ki of 0.28 nM at CB2 and 52.3 nM at the CB1 receptor, giving it around 180 times selectivity for CB2. The 2-methyl and 6-nitro groups on the indole ring both tend to increase CB2 affinity while generally reducing affinity at CB1, explaining the high CB2 selectivity of AM-1221.