反应详情

Dry acetonitrile (1.8 ml) was added to a solution of n-butyl lithium (a 2.5M solution in hexane, 13.8 ml) in dry THF (30 ml) at -78° C. and the mixture was stirred at the same temperature for 1 hour to which was subsequently added a solution of methyl 3,4-dimethoxybenzoate (6.42 g) in dry THF (15 ml). The mixture was stirred at -78° C. for 3 hours and then at room temperature for 1 hour. Water (100 ml) was added to the reaction solution and the resultant mixture was extracted with ethyl ether (100 ml). After the aqueous layer was acidified with 6 N hydrochloric acid, it was extracted with ethyl acetate (200 ml×3). The organic layers were combined, washed with saturated brine and then dried over anhydrous sodium sulfate. Then, the solvent was distilled away under a reduced pressure. The resultant residue was crystallized from ethyl acetate-hexane to obtain the title compound (3.6 g) as pale yellow crystals.

1. stirringThe mixture was stirred at -78° C. for 3 hours
2. waitat room temperature for 1 hour
3. extractionthe resultant mixture was extracted with ethyl ether (100 ml)
4. extractionwas extracted with ethyl acetate (200 ml×3)
5. washwashed with saturated brine
6. dry with materialdried over anhydrous sodium sulfate
7. distillationThen, the solvent was distilled away under a reduced pressure
8. customThe resultant residue was crystallized from ethyl acetate-hexane