PubMed · 16121964
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Aaron S Dumont, Neal F Kassell. 2005. Vasospasm.. https://doi.org/10.3171/jns.2005.103.1.0001
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The RS and SR enantiomers of 2-oxazolidinone and 1,4-benzodioxane bearing a 2-pyrrolidinyl substituent at the 5- and 2-position, respectively, were synthesized as candidate nicotinoids. One of the two benzodioxane stereoisomers reasonably fits the pharmacophore elements of (S)-nicotine and binds at alpha4beta2 nicotinic acetylcholine receptor with submicromolar affinity. Interestingly, both the synthesized pyrrolidinylbenzodioxanes exhibit analogous affinity at alpha(2) adrenergic receptor resembling the behaviour of some known alpha(2)-AR ligands recently proved to possess neuronal nicotinic affinity.
In the course of the synthesis of gamma-pyrones, well-known inhibitors of photosystem II electron transport, it turned out that the starting material, acyl derivatives of 2,2-dimethyl-1,3-dioxane-5,6-dione (Meldrum's acid) are potent inhibitors of photosystem II electron transport. Thus, in a simple one-step synthesis from commercial available substances, highly potent photosystem II inhibitors are generated. The biological activity of the acyl derivatives is in a parabolic fashion dependent from the length of the alkyl side chain.
This research investigates the effect of adding oxidants such as Fe0, Fe2+ and S2O8(2-) in the sonication of 1,4-dioxane (1,4-D). The results indicate that the degradation pattern of 1,4-D kinetically could be divided into three steps (initiation, acceleration, and stabilization), with the first two steps predominating. The initiation step agreed with zero order rate model, while the acceleration step was the pseudo-first order. In the presence of HCO3- as a radical scavenger, the degradations of 1,4-D and TOC were suppressed, indicating that OH radical is an important factor in the sonolysis, especially at the acceleration step. The overall degradation efficiency of 79.0% in the sonolysis of 1,4-D was achieved within 200 min. While Fe0, Fe2+ and S2O8(2-) were individually combined with sonication, the total degradation efficiency of 1,4-D increased 18.6%, 19.1% and 16.5% after 200 min, respectively. The addition of oxidants not only increased the rate constant in the acceleration step, but also changed the kinetic model from zero to pseudo-first order at the initiation step. The addition of oxidants such as Fe2+, Fe0 and S2O8(2-) in the sonication of 1,4-D also improved the mineralization of 1,4-D. However, the degradation efficiencies of 1,4-D and TOC were not statistically different (p = 0.709, ANOVA) with different oxidants such as Fe2+, Fe0 and S2O8(2-).