25I-NBOH (NBOH-2CI, Cimbi-27, 2-C-I-NBOH) is a derivative of the phenethylamine derived hallucinogen 2C-I that was discovered in 2006 by a team at Purdue University. It acts as a potent agonist for the 5HT2A receptor, with a Ki of 0.061nM at the human 5HT2A receptor, similar to the better-known compound 25I-NBOMe, making it some twelve times the potency of 2C-I itself. In vitro tests showed this compound acted as an agonist but animal studies have not been reported. While the N-benzyl derivatives of 2C-I were significantly increased in binding activity to 5HT2A receptor fragments, compared to 2C-I, the N-benzyl derivatives of DOI were less active, compared to DOI.
25I-NBOH is notable as one of the most selective agonist ligands for the 5-HT2A receptor with an EC50 value of 0.074 nM and more than 400x selectivity over the 5-HT2C receptor.