反应详情

A mixture of 3-nitrophenyl acetic acid (20 g), pyridine (44 g) and acetic anhydride (106 g) was refluxed for four hours. Complete disappearance of starting material was observed by tlc (silica gel eluted with 1:1 parts by volume diethyl ether:hexane), and the brown solution was then evaporated to dryness in vacuo at 40°. The resulting residue was refluxed in the presence of concentrated HCl (7.5 ml) and ethanol (78 ml) for one hour; and to the hydrolysis product was added ice water (400 ml) and the precipitating 3-nitrophenyl acetone was filtered and washed with water. Additional product was obtained by extracting the filtrate with methylene chloride, drying over sodium sulfate, and evaporating the organic solvents. The crude products were combined and dissolved in a minimum amount of methanol:methylene chloride (1:1 parts by volume). Silica gel (30-50 g, flash chromatography, EM 230-400 mesh) was added and the solvent evaporated. The dried silica gel was placed on a column (3 in.×6 in.) containing the same silica gel and eluted with 4:6 parts by volume ethyl acetate:hexane. The solution containing the desired product was evaporated to give the title compound. NMR for this product (in CDCl3) shows a 3 proton singlet at 2.34 ppm; a 2 proton singlet at 3.63 ppm; a 2 proton multiplet at 7.5 ppm; and a 2 proton multiplet at 8.0 ppm.

1. temperaturewas refluxed for four hours
2. washComplete disappearance of starting material was observed by tlc (silica gel eluted with 1:1 parts by volume diethyl ether:hexane)
3. customthe brown solution was then evaporated to dryness in vacuo at 40°
4. temperatureThe resulting residue was refluxed in the presence of concentrated HCl (7.5 ml) and ethanol (78 ml) for one hour
5. additionand to the hydrolysis product was added ice water (400 ml)
6. filtrationthe precipitating 3-nitrophenyl acetone was filtered
7. washwashed with water
8. customAdditional product was obtained
9. extractionby extracting the filtrate with methylene chloride
10. dry with materialdrying over sodium sulfate
11. customevaporating the organic solvents
12. dissolutiondissolved in a minimum amount of methanol:methylene chloride (1:1 parts by volume)
13. additionSilica gel (30-50 g, flash chromatography, EM 230-400 mesh) was added
14. customthe solvent evaporated
15. additioncontaining the same silica gel
16. washeluted with 4:6 parts by volume ethyl acetate
17. additionThe solution containing the desired product
18. customwas evaporated