反应详情

Sodium carbonate (0.125 g, 0.0012 mol) is added to a solution of 1-{4-[5-(2-fluorobiphenyl-4-yl)-1,2,4-oxadiazole-3-yl]benzyl}piperidine-4,4-dicarboxylic acid mono benzyl ester (0.35 g, 0.00059 mol) in N,N-dimethylacetamide (3.5 mL). The reaction mixture is stirred for 30 minutes at room temperature. Chloromethyl pivalate (0.187 g, 0.0012 mol) is added to the reaction mixture which is then heated at 65° C. for 4 hrs. The reaction mixture is treated with demineralized water (5 mL) and extracted in ethyl acetate (2×5 mL). Sodium chloride (0.25 g) is added to the ethyl acetate layer and stirred for 15 minutes. Demineralized water (5 mL) is added to the ethyl acetate layer and the layers are separated. The ethyl acetate layer is dried over sodium sulphate. Removal of solvent under reduced pressure gives a viscous liquid, which is purified by column chromatography (silica gel 230-400 mesh, n-hexane:ethyl acetate 70:30) to furnish 1-{4-[5-(2-fluorobiphenyl-4-yl)-1,2,4oxadiazol-3-yl]benzyl}-piperidine-4,4-dicarboxylic acid benzyl ester (2,2-dimethylpropanoyloxymethyl) ester.

1. temperatureis then heated at 65° C. for 4 hrs
2. extractionextracted in ethyl acetate (2×5 mL)
3. additionSodium chloride (0.25 g) is added to the ethyl acetate layer
4. stirringstirred for 15 minutes
5. additionDemineralized water (5 mL) is added to the ethyl acetate layer
6. customthe layers are separated
7. dry with materialThe ethyl acetate layer is dried over sodium sulphate
8. customRemoval of solvent under reduced pressure
9. customgives a viscous liquid, which
10. customis purified by column chromatography (silica gel 230-400 mesh, n-hexane:ethyl acetate 70:30)