JWH-098 is a synthetic cannabinoid receptoragonist from the naphthoylindole family. It is the indole 2-methyl derivative of a closely related compound JWH-081, but has markedly different affinity for the CB1 and CB2 receptors. While JWH-081 is around tenfold selective for CB1 over CB2, in JWH-098 this is reversed, and it is around four times weaker than JWH-081 at CB1 while being six times more potent at CB2, giving it a slight selectivity for CB2 overall. This makes JWH-098 a good example of how methylation of the indole 2-position in the naphthoylindole series tends to increase CB2 affinity, but often at the expense of CB1 binding.[2]
^Huffman JW, Zengin G, Wu MJ, Lu J, Hynd G, Bushell K, et al. (January 2005). "Structure-activity relationships for 1-alkyl-3-(1-naphthoyl)indoles at the cannabinoid CB(1) and CB(2) receptors: steric and electronic effects of naphthoyl substituents. New highly selective CB(2) receptor agonists". Bioorganic & Medicinal Chemistry. 13 (1): 89–112. doi:10.1016/j.bmc.2004.09.050. PMID15582455.