Narcotic drug methohexital: synthesis by enantioselective catalysis

Quantitative Determination of Methohexital in Human Whole Blood by Liquid Chromatography Tandem Mass Spectrometry

A rapid, simple and sensitive liquid chromatography tandem mass spectrometry method for the determination of methohexital in human whole blood was developed and validated. Ethyl acetate/n-hexane (9:1) was used as extraction solvent while aprobarbital was used as internal standard. Methohexital was recovered by liquid-liquid extraction from 100 μL of human whole blood. The mobile phase was water-acetonitrile, and an ACQUITY BEH C18 (2.1 × 100 mm, 1.7 μm) column was adopted. Negative electrospray ionization source and multiply reaction monitoring mode were applied. The transitions of m/z were 261.2/42.2 and 261.2/119.0 for methohexital. The limit of detection was 0.5 ng/mL, which was lower than the previous methods. Wide linear range (2-2,000 ng/mL) with a good correlation coefficient (r > 0.99) was also obtained. The intra- and inter- day precisions represented by relative standard deviation were <11.5%, and the recoveries were >79.67%. This analytical method involved small sample volume and had been proven to be rapid, easy, sensitive and specific. Therefore, it could be used for the clinical analysis of methohexital.

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

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 α1β2/3γ2L GABA(A) receptors. Finally, R-(-)-14 was found to be an exceptionally efficient photolabeling reagent, incorporating into both α1 and β3 subunits of human α1β3 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.