- Cholinergic agents: Effect of methyl substitution in a series of arecoline derivatives on binding to muscarinic acetylcholine receptors
-
Arecoline, arecaidine, and a series of derivatives, differing by the presence or absence of methyl groups at positions on the periphery of the molecule, were prepared, and their binding to muscarinic acetylcholine receptors was tested. On the basis of this study, muscarinic agonism for arecoline series is governed by strict structure-activity relationships, as previously observed for other agonist series. Only minor changes in nitrogen substitution were tolerated in the present series of arecoline derivatives.
- Moos,Bergmeier,Coughenour,Davis,Hershenson,Kester,McKee,Marriott,Schwarz,Tecle,Thomas
-
p. 1015 - 1019
(2007/10/02)
-
- NOUVEAUX MODELES DU NADH EN SERIE OXAZOLYL-3 DIHYDRO-1,4 PYRIDINE: SYNTHESE, REACTIVITE, ROLE DE LA COMPLEXATION DANS LA REACTIVITE
-
A new class of NADH models is described: they contain the 3-oxazolyl-1,4-dihydropyridine structure.They have been synthesized by regioselective addition at the 4 position of organometallic derivatives (one of them bearing a chiral group) on 3-(4,4-dimethyl-2-oxazolyl)pyridine.The 1,4-dihydropyridine structure is obtained after quaternarization and reduction by sodium dithionite.Quaternarization through Zincke's reaction leads to models having a chiral group at the pyridine nitrogen.This chirality is necessary to induce asymmetry at the 4 carbon in the corresponding 1,4-dihydropyridine.This asymmetry plays an important role in the low enantioselectivity of reduction of a prochiral substrate such as methyl benzoylformate.The chemical reactivity of the models has been studied by performing the reduction of p-nitrobenzaldhyde in the presence of magnesium perchlorate.All models gave quantitative yields.However, reactions are slower than those performed, in the same conditions, with N-benzyl-1,4-dihydronicotinamide (BNAH).A 13C nmr study shows that this behaviour is probably a consequence of the high complexation of magnesium with the oxazoline moiety.
- Binay, P.,Dupas, G.,Bourguignon, J.,Queguiner, G.
-
p. 648 - 655
(2007/10/02)
-
- The Addition-Elimination Mechanism in the Nucleophilic Heteroaromatic Substitution of 3-(4',4'-Dimethyl-4',5'-dihydro-oxazol-2'-yl)pyridine. Solvent Effect on the Regiochemistry of the Addition Reaction
-
The nucleophilic heteroaromatic substitution of 3-(4',4'-dimethyl-4',5'-dihydro-oxazol-2'-yl)pyridine (3) with organolithium compounds has been studied.The reaction of (3) with butyl-lithium gave a mixture of the corresponding 2,3-, 3,4-, and 2,5-disubsti
- Hauck, Albert E.,Giam, C. S.
-
p. 2227 - 2232
(2007/10/02)
-
- Substitutions on Pyridines Activated by Oxazolines via Nucleophilic Additions or Metalation-Alkylation
-
Pyridyloxazolines, derived from nicotinic acid or isonicotinic acid, have been shown to metalate at the 4- and 3-positions, respectively.These react with a variety of electrophiles to provide 4- and 3-substituted pyridines in good yield.Alternatively, 3-pyridyloxazolines, when treated with organolithium or Grignard reagents, give addition to the 4-position and provide a series of 4-substituted 1,4-dihydropyridines.
- Meyers, A. I.,Gabel, Richard A.
-
p. 2633 - 2637
(2007/10/02)
-
- Regioselective Nucleophilic Addition of Organolithium Compounds to 3-(4,4-Dimethyloxazolin-2-yl)pyridine
-
The nucleophilic heteroaromatic addition reactions of 3-(4,4-dimethyloxazolin-2-yl)pyridine (8) with organolithium compounds as nucleophilic reagents have been investigated.Strongly nucleophilic reagents have been observed to add preferentially to the γ-
- Hauck, Albert E.,Giam, Choo-Seng
-
p. 2070 - 2076
(2007/10/02)
-
