ABSTRACT
We report a novel 'fluorescent dopamine' that possesses essential features of natural dopamine. Our method is simple and is readily extended to monoamine neurotransmitters such as L-norepinephrine, serotonin and GABA, providing a more practical approach. Because of its compatibility with sensitive fluorescent measurements, we envisage that our approach will have a broad range of applications in neural research.
Subject(s)
Dopamine/metabolism , Fluorescein-5-isothiocyanate/chemistry , Fluorescent Dyes/chemistry , Molecular Imaging/methods , Neurotransmitter Agents/metabolism , Synaptic Transmission , Animals , Biological Transport , CHO Cells , Cricetulus , Fluorometry/methods , PC12 Cells , RatsABSTRACT
The effects of important reaction parameters on the enhancement of sialic acid derivative lipophilic properties through the lipase-catalyzed esterification of N-acetyl neuraminic acid methyl ester are investigated in this study. It is found that the lipase Novozym 435 from Candida antarctica is particularly useful in the preparation of sialic acid methyl ester monononanoate (SAMEMN). The optimum temperature for the SAMEMN synthesis reaction using Novozym 435 is 60°C, and nonanoic anhydride is found to be the best substrate among all acyl donors. The Novozym 435-catalyzed esterification of N-acetyl neuraminic acid methyl ester gave a maximum yield of 87.7% after 6h in acetonitrile at 60°C. Because the novel method developed is simple, yet effective, it could potentially be used industrially for the production of sialic acid derivatives.
Subject(s)
Candida/enzymology , Enzymes, Immobilized/metabolism , Lipase/metabolism , N-Acetylneuraminic Acid/biosynthesis , Biocatalysis , Esters/metabolism , Fungal Proteins , Solvents , Temperature , Time FactorsABSTRACT
The syntheses of three fused bicyclic enones, including 1,2,6,6a-tetrahydro-1-tosyl-cyclopenta[b]pyrrol-3(5H)-one, 1,2,3,6,7,7a-hexahydro-4H-1-tosyl-cyclopenta[b]pyridin-4-one and 1,2,5,6,7,7a-hexahydro-3H-1-tosyl-indol-3-one, via anionic cyclization and Diels-Alder reactions with various dienes to construct novel nitrogen-containing angular tricyclic skeletons are described.
ABSTRACT
The generation of alpha-carbonyl vinyl radicals from alpha-iodo cycloalkenones, the scope of their participation in intermolecular addition reactions with electron-withdrawing olefins are studied and a synthetic study of the formal synthesis of enantiopure fawcettimine using this reaction is described.
