ABSTRACT
3- and 4-(Aminomethyl)-2,6-difuorophenols were tested for activity against the three major classes of GABA receptors. 4-(Amninomethyl)-2,6difluorophenol was shown to be a competitive and somewhat selective antagonist at p1 GABA(C) receptors expressed in Xenopus oocytes (K(B) = 75.5 microM with a 95% Confidence Interval range of 75.2 microM to 75.8 microM). This is the first in a novel class of increased lipophilicity GABA(C) receptor antagonists with little activity at alpha1beta2gamma2 GABA(A) and GABA(B) receptors.
Subject(s)
GABA Antagonists/chemical synthesis , Phenols/chemical synthesis , Receptors, GABA/drug effects , Animals , Brain/metabolism , GABA Antagonists/pharmacology , Humans , Molecular Structure , Oocytes , Patch-Clamp Techniques , Phenols/pharmacology , Rats , Receptors, GABA/metabolism , Receptors, GABA-A/metabolism , Receptors, GABA-B/metabolism , XenopusABSTRACT
3-(Aminomethyl)-2,6-difluorophenol (6) and 4-(aminomethyl)-2, 6-difluorophenol (7) were synthesized in eight and four steps, respectively, starting from 2,6-difluorophenol, to test the potential of the 2,6-difluorophenol moiety to act as a lipophilic bioisostere of a carboxylic acid. Compounds 6 and 7 are potential bioisosteric analogues of gamma-aminobutyric acid (GABA). Substrate studies and inhibition studies were carried out with pig brain gamma-aminobutyric acid aminotransferase; 6 and 7 are very poor substrates, but both inhibit the enzyme, indicating that the 2, 6-difluorophenol moiety appears to be able to substitute for a carboxylic acid to increase the lipophilicity of drug candidates.
