Assessing the impact of protonating acid combinations in e-cigarette liquids: a randomised, crossover study on nicotine pharmacokinetics.

The addition of protonating acids to e-cigarette liquid formulations (e-liquids) enhances nicotine bioavailability in e-cigarette use. However, little is known about the impact of different combinations of protonating acid on nicotine pharmacokinetics. The objectives of this study were to compare pharmacokinetics of nicotine absorption following use of a closed-system e-cigarette, containing e-liquids with two different nicotine levels and with different ratios of three common protonating acids-lactic, benzoic and levulinic.

Synthesis of symmetrical and unsymmetrical pyrazines.

Opening of representative epoxides with 1,2-amino alcohols delivered the amino diols. The product amino diols were then oxidized under Swern conditions. The amino diketones so prepared were not isolated, but were condensed directly with hydroxylamine to give the substituted pyrazines.

Computationally guided organometallic chemistry: preparation of the heptacyclic pyrazine core of ritterazine N.

Diels-Alder cycloaddition of 10 followed by Wittig homologation and intramolecular diene cyclozirconation of the resulting triene under equilibrating conditions led to the tricyclic 6-6-5 ketone 5 with high diastereocontrol. The derived alpha-azido ketone 16 cyclized efficiently to the heptacyclic pyrazine core of ritterazine N.