- 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)
-