- Synthetic Studies on O-Heterocycles via Cycloadditions. Part 2. Adducts from Styrene Oxides
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The styrene oxides (14) and (15), bearing electron-withdrawing functions, readily undergo thermal and photochemical (triplet sensitised) dipolar cycloadditions with simple electron-deficient olefins, regioselectively in the case of methyl acrylate.However, cycloadditions with 5-arylbutenolides as dipolarophiles, required for lignan synthesis, could not be effected in significant yield.A new short route to 5-arylbut-2-enolides was devised.The dihydro- and tetrahydro-furan adducts (18d), (19d), and (20d) all fragment in base to the dienol nitrile (25).
- Clawson, Paul,Lunn, Patricia M.,Whiting, Donald A.
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p. 159 - 162
(2007/10/02)
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- Analogues of γ-hydroxybutyric acid. Synthesis and binding studies
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Substituted 4-hydroxybutyric (GHB) or trans-4-hydroxycrotonic acids (T-HCA) and structurally related compounds were synthesized and submitted to [3H]GHB binding. Structure-activity relationship studies highlighted for [3H]GHB binding (a) the necessity of a nonlactonic, relatively extended conformation of the γ-hydroxybutyric chain, (b) the existence of some bulk tolerance in the vicinity of the hydroxyl group, and (c) the high sensitivity toward isosteric replacement of the carboxyl or the hydroxyl groups. T-HCA has been recently identified as a naturally occurring substance in the central nervous system (CNS) and shows a better affinity than GHB. Our findings are in favor of the presence in the CNS of specific GHB binding sites, which are different from the GABA and the picrotoxin binding sites, and for which T-HCA may be an endogenous ligand.
- Bourguignon,Schoenfelder,Schmitt,Wermuth,Hechler,Charlier,Maitre
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p. 893 - 897
(2007/10/02)
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