pf-03654746 pf-03654746 pf-03654746 is a potent and selective histamine h3 receptor antagonist developed by pfizer and currently undergoing clinical trials for the treatment of adhd, tourette syndrome as well as potential anti-allergy applications. pf-03654746identifiers iupac name trans-n-ethyl-3-fluoro-3-cyclobutanecarboxamide cas number935840-31-6 ypubchem cid16119086chemspider25069700uniig3qe979k1xchemical and physical dataformulac18h24f2n2omolar mass322.392 g·mol−13d model (jsmol)interactive image smiles ccnc(=o)1c(c1)(f)c2=cc(=c(c=c2)cn3cccc3)f inchi inchi=1s/c18h24f2n2o/c1-2-21-17(23)14-10-18(20,11-14)15-6-5-13(16(19)9-15)12-22-7-3-4-8-22/h5-6,9,14h,2-4,7-8,10-12h2,1h3,(h,21,23)/t14-,18-key:sxmbkhydzocbmt-ppuggxlssa-n (verify)