The toxic hallucinogen 25B-NBOMe is very rapidly degraded by human liver microsomes and has low oral bioavailability. Herein we report on the synthesis, microsomal stability and 5-HT2A/5-HT2C receptor profile of novel analogs of 25B-NBOMe modified at the primary site of metabolism. Although microsomal stability could be increased while maintaining potent 5-HT2 receptor agonist properties, all analogs had an intrinsic clearance above 1.3 L/kg/h predictive of high first-pass metabolism.