反应详情

Methyl 4-hydroxy-3-(methyloxy)benzoate (methyl vanillate, Aldrich) (3.85 g, 21.1 mmol) and potassium carbonate (2.92 g, 21.1 mmol) in DMF (10 mL) was treated at RT with 2-chloro-N,N-dimethylacetamide (Merck) (2.18 mL, 21.1 mmol) and the mixture was stirred over the weekend. The mixture was partitioned between ethyl acetate and 2M HCl. The organic phase was washed with, 2M HCl, saturated sodium bicarbonate solution (turns lightly coloured), acid (loses colour), brine, dried (MgSO4), and evaporated under reduced pressure, to give the product contaminated with starting material (5.0 g). The mixture was therefore re-dissolved in DMF (5 mL) and treated with potassium carbonate (1.38 g, 10 mmol) and 2-chloro-N,N-dimethylacetamide (1 mL, 10 mmol) for another day. The mixture was then partitioned between ethyl acetate and 2M HCl and treated as above. The filtrate was evaporated to give a solid (2.614 g) which was loaded in chloroform to a silica cartridge (70 g) and purified by chromatography on Flashmaster using a 0-100% ethyl acetate-cyclohexane gradient over 30 min. The appropriate fractions were combined and evaporated in vacuo to give the title compound (1.4 g, 25%) as a white solid. LCMS (System A) RT=0.69 min, ES+ve m/z 268 (M+H)+.

1. customThe mixture was partitioned between ethyl acetate and 2M HCl
2. washThe organic phase was washed with, 2M HCl, saturated sodium bicarbonate solution (
3. dry with materialdried (MgSO4)
4. customevaporated under reduced pressure
5. customto give the product
6. customThe mixture was then partitioned between ethyl acetate and 2M HCl
7. additiontreated as above
8. customThe filtrate was evaporated