[C:1]([C:5]1[C:6]([OH:13])=[C:7]([CH:10]=[CH:11][CH:12]=1)[CH:8]=[O:9])([CH3:4])([CH3:3])[CH3:2].[CH3:14][O:15][C:16]1[CH:23]=[CH:22][C:19]([CH2:20]Cl)=[CH:18][CH:17]=1.C([O-])([O-])=O.[K+].[K+].CC#N>CCOC(C)=O>[C:1]([C:5]1[C:6]([O:13][CH2:20][C:19]2[CH:22]=[CH:23][C:16]([O:15][CH3:14])=[CH:17][CH:18]=2)=[C:7]([CH:10]=[CH:11][CH:12]=1)[CH:8]=[O:9])([CH3:4])([CH3:2])[CH3:3]
A suspension of 3-tert-butyl-2-hydroxybenzaldehyde (5.0 g, 28.1 mmol, 1.0 equiv), 4-methoxybenzyl chloride (4.4 g, 3.8 mL, 28.1 mmol, 1.0 equiv), powdered K2CO3 (7.8 g, 56.2 mmol, 2.0 equiv) and MeCN (100 mL) was refluxed for 6 hr. The yellow-green suspension was cooled to room temperature and allowed the stand for 48 hr. The suspension was diluted with EtOAc (50 mL) and filtered, washing the solids with EtOAc (50 mL). The filtrate was concentrated under reduced pressure to give brown oil. The oil was dissolved in EtOAc (150 mL) and the solution washed with H2O (125 mL) and brine (100 mL). The organic phase was dried over Na2SO4, filtered and the solution concentrated under reduced pressure to give a brown oil. The crude product was absorbed onto silica gel using dichloromethane and dry-loaded onto a column of silica gel (100 g) packed in heptanes. The column was eluted with heptanes (500 mL) followed by 2.5% EtOAc/heptanes (1000 mL). Product fractions were concentrated under reduced pressure to give a yellow oil. Seeding (seeds obtained by lengthy scratching with cold hexanes) of the oil induced crystallization. After crystallization was complete the yellow solid was pumped under high vacuum for 0.5 hr to give 7.5 g (89%) of 24.
Wird geladen…
