反应详情

While cooling with an ice bath 1.35 g of sodium were dissolved in 30 ml of methanol and subsequently a solution of 4.65 g of 3-chloro-4-fluorobenzaldehyde and 6.75 g of methyl azidoacetate in 10 ml of methanol were added within 20 min. The reaction mixture was stirred at room temperature for 3 hours and then neutralized with 2N HCl. The mixture was extracted with ethyl acetate, washed with water and saturated sodium chloride solution and the organic phase was dried over sodium sulfate. The solvent was removed and the residue was chromatographed over 250 g of silica gel with n-hexane-toluene 2:1. There were obtained 2.5 g (33%) of methyl 3-chloro-4-fluoro-a-azidocinnamate as yellow crystals with m.p. 72°-74°.

1. extractionThe mixture was extracted with ethyl acetate
2. washwashed with water and saturated sodium chloride solution
3. dry with materialthe organic phase was dried over sodium sulfate
4. customThe solvent was removed
5. customthe residue was chromatographed over 250 g of silica gel with n-hexane-toluene 2:1