[C:1]([O:7][CH2:8][C:9]1[CH:14]=[C:13]([C:15](=[O:17])[CH3:16])[CH:12]=[CH:11][C:10]=1[O:18][CH3:19])(=[O:6])[C:2]([CH3:5])([CH3:4])[CH3:3].CC(O[CH:25](N(C)C)[N:26]([CH3:28])[CH3:27])(C)C.O.CCCC(C)C>C(OC)(C)(C)C>[C:1]([O:7][CH2:8][C:9]1[CH:14]=[C:13]([C:15](=[O:17])/[CH:16]=[CH:25]/[N:26]([CH3:28])[CH3:27])[CH:12]=[CH:11][C:10]=1[O:18][CH3:19])(=[O:6])[C:2]([CH3:4])([CH3:3])[CH3:5]
5-acetyl-2-methoxybenzyl pivalate (66.24 g, 251.7 mmol) was added to Bredereck's reagent (175.5 g, 1000.7 mmol) held under a nitrogen atmosphere. The resulting solution was heated at 54° C. for 240 minutes. Water (600 mL) was then added and the mixture allowed to stir for an hour. Methyl tert-butyl ether was then added (500 ml) and the mixture stirred and allowed to settle. The upper organic layer was separated off and retained. Further methyl-tert-butyl ether was then added (500 ml) and the mixture stirred and allowed to settle. The upper organic layer was separated off and combined with the original upper organic layer. The combined organic layers were washed twice with water (2×300 mL), discarding the two lower aqueous washes. Solvent (850 mL) is removed from the reaction by atmospheric distillation and iso-hexane (100 mL) added. The clear solution was allowed to cool to 20° C. whereby a white, crystalline solid was obtained. Further iso-hexane (50 mL) was added and the solid filtered off at around 20° C. The solid was washed twice with fresh iso-hexane (2×100 mL) and dried to constant weight to afford 64 g of the desired 5-[(2E)-3-(dimethylamino)prop-2-enoyl]-2-methoxybenzyl pivalate (2).
Wird geladen…
