4-fluorophenibut 4-fluorophenibut 4-fluorophenibut (developmental code name cgp-11130; also known as β-(4-fluorophenyl)-γ-aminobutyric acid or β-(4-fluorophenyl)-gaba) is a gabab receptor agonist which was never marketed. it is selective for the gabab receptor over the gabaa receptor (ic50 = 1.70 μm and > 100 μm, respectively). the drug is a gaba analogue and is closely related to baclofen (β-(4-chlorophenyl)-gaba), tolibut (β-(4-methylphenyl)-gaba), and phenibut (β-phenyl-gaba). it is less potent as a gabab receptor agonist than baclofen but more potent than phenibut. 4-fluorophenibutclinical dataother namescgp-11130; β-(4-fluorophenyl)-γ-aminobutyric acid; β-(4-fluorophenyl)-gaba; baflofen; fluorophenibut; f-phenibut; fluoributroutes ofadministrationby mouthidentifiers iupac name 4-amino-3-(4-fluorophenyl)butanoic acid cas number52237-19-1pubchem cid103611chemspider93547unii6dau7m5p3dchemical and physical dataformulac10h12fno2molar mass197.209 g·mol−13d model (jsmol)interactive image smiles c1=cc(=cc=c1c(cc(=o)o)cn)f inchi inchi=1s/c10h12fno2/c11-9-3-1-7(2-4-9)8(6-12)5-10(13)14/h1-4,8h,5-6,12h2,(h,13,14)key:qwhxhldnsxlapx-uhfffaoysa-n the substance is sometimes referred to as 4f-phenibut or f-phenibut and colloquially as fluorobut. legal status f-phenibut is a prohibited substance in lithuania and hungary.