反应详情

Dimethyl 4-nitro-1H-pyrazole-3,5-dicarboxylate (WO00/24745, page 48, preparation 2) (2.0 g, 8.83 mmol) was added to a solution of 2-ethoxyethyl bromide (1.18 mL, 10.45 mmol) and potassium carbonate (1.32 g, 9.56 mmol) in N,N-dimethylformamide (35 mL) and the reaction mixture stirred for 48 hours at room temperature. The reaction mixture was concentrated in vacuo and the residue partitioned between ethyl acetate (200 mL) and water (100 mL). The organic layer was separated, dried over magnesium sulphate and concentrated in vacuo. The crude product was purified by column chromatography on silica gel eluting with pentane:ethyl acetate 100:0 to 70:30 to yield the ester product, 1.63 g.

1. concentrationThe reaction mixture was concentrated in vacuo
2. customthe residue partitioned between ethyl acetate (200 mL) and water (100 mL)
3. customThe organic layer was separated
4. dry with materialdried over magnesium sulphate
5. concentrationconcentrated in vacuo
6. customThe crude product was purified by column chromatography on silica gel eluting with pentane:ethyl acetate 100:0 to 70:30