Synthesis, pharmacology and X-ray studies of baclofen analogues
摘要:
Baclofen (beta-p-chlorophenyl-GABA) is the reference selective agonist for the bicuculline-insensitive GABA(B) receptor. The search for new compounds having a high affinity for the GABA(B) receptor is very important to clarify structural requirements. In that sense, we report the synthesis, binding studies and X-ray determinations of various 3-heteroaromatic gamma-aminobutyric acids. Biochemical investigations concerning their abilities to displace [H-3] muscimol (GABAA) and [H-3] baclofen (GABA(B)) in binding studies showed that the 4-amino-3-(5-methoxybenzo[b]furan-2-yl)butanoic acid 6a (IC50 = 22.16-mu-M/R (-) [H-3] baclofen; IC50 = 5.6-mu-M/RS [H-3] baclofen) has a specific affinity for the GABA(B) receptor. The crystal structure of compounds 6a and 6b associated with computer graphics molecular superimpositions allows some structural requirements for GABA(B) receptor ligands to be proposed.