C([Li])CCC.Br[C:7]1[CH:8]=[N:9][CH:10]=[C:11]([Br:14])[C:12]=1[CH3:13].CN([CH:18]=[O:19])C.[NH4+].[Cl-]>CCCCCC>[Br:14][C:11]1[C:12]([CH3:13])=[C:7]([CH:18]=[O:19])[CH:8]=[N:9][CH:10]=1Under argon, an n-butyllithium solution in hexane (1.55N, 4.6 ml) is added dropwise to a 3,5-dibromo-4-methylpyridine solution (intermediate 10.1, 1.76 g, 7 mmol) kept at −100° C. After stirring for 5 min, DMF (0.84 ml, 1.54 equiv.) is added dropwise. The stirring is maintained for 20 min at −100° C. and then for 1 h at −78° C. An aqueous NH4Cl solution is added and the reaction mixture is extracted with a diethyl ether/water mixture. The yellow solid obtained is purified on silica gel (100 g), eluting with AcOEt/petroleum ether (1/4).
Wird geladen…
