Allyl m-trifluoromethyldiazirine mephobarbital: an unusually potent enantioselective and photoreactive barbiturate general anesthetic.

ABSTRACT: We synthesized 5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (14), a trifluoromethyldiazirine-containing derivative of general anesthetic mephobarbital, separated the racemic mixture into enantiomers by chiral chromatography, and determined the configuration of the (+)-enantiomer as S by X-ray crystallography. Additionally, we obtained the (3)H-labeled ligand with high specific radioactivity. R-(-)-14 is an order of magnitude more potent than the most potent clinically used barbiturate, thiopental, and its general anesthetic EC(50) approaches those for propofol and etomidate, whereas S-(+)-14 is 10-fold less potent. Furthermore, at concentrations close to its anesthetic potency, R-(-)-14 both potentiated GABA-induced currents and increased the affinity for the agonist muscimol in human ?1?2/3?2L GABA(A) receptors. Finally, R-(-)-14 was found to be an exceptionally efficient photolabeling reagent, incorporating into both ?1 and ?3 subunits of human ?1?3 GABA(A) receptors. These results indicate R-(-)-14 is a functional general anesthetic that is well-suited for identifying barbiturate binding sites on Cys-loop receptors.

SUBMITTER: Savechenkov PY 

PROVIDER: S-EPMC3717557 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature