Methanol → 5-(2,3-Dihydro-6-methyl-4-oxo-5-phenyl-1,3-oxazin-3-yl)-5-methyl-2,4-hexanedione
Reaktionsgleichung
[Mg].[CH3:2][C:3]1[O:8][CH2:7][N:6]([C:9]([CH3:17])([CH3:16])[C:10](=[O:15])[CH2:11][C:12]([O-:14])=O)[C:5](=[O:18])[C:4]=1[C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1.[CH3:25]O>>[CH3:2][C:3]1[O:8][CH2:7][N:6]([C:9]([CH3:17])([CH3:16])[C:10](=[O:15])[CH2:11][C:12](=[O:14])[CH3:25])[C:5](=[O:18])[C:4]=1[C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1Komponenten
4
Reaktionsbedingungen
- Temperatur
- 60 °C
Versuchsvorschrift
A suspension of magnesium turnings (100 mg) in methanol was stirred whilst a solution of t-butyl [4-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-1,3-oxazin-3-yl)-4-methyl-3-oxo-pentanoate (1.40 g) in methanol was added. The mixture was heated at 60° C. for 1 hour, cooled and evaporated. Toluene was added and the mixture re-evaporated. The residue was redissolved in toluene and a solution of acetyl chloride (300 mg) added. The mixture was stirred at 20° C. for 1 day, then hydrochloric acid (2M) added and the stirring continued for another 1 hour. The organic phase was washed with hydrochloric acid (2M) then with water and dried (magnesium sulphate) 4-Toluene-sulphonic acid (50 mg) was added and the mixture stirred at 80° C. for 1 hour, cooled and washed in turn with saturated sodium bicarbonate solution and water, dried (magnesium sulphate) and evaporated to give 5-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-1,3-oxazin-3-yl)-5-methyl-2,4-hexanedione (Compound 193, 0.15 g) as a brown gum, NMR 1.56(s,6H), 1.91(s,3H), 2.15(s,3H), 3.66 and 3.70(s,1H), 5.25(t,2H), 7.20-7.44(m,5H).