Dimethyl Sulfate → HCID 59105415, compound

Participants

Reaction Steps

A solution of methyl (4-benzyloxy-1,3-dimethyl-pyrazol-5-yl)acetate (2.5 g, 9.1 mmol) and methyl formate (15 g, 250 mmol) in anhydrous DMF (10 ml) was added dropwise to a suspension of sodium hydride (60% dispersion in oil) (0.55 g, 13.8 mmol) in anhydrous DMF (5 ml), while the temperature being maintained below 10° C. by cooling on ice. After stirring at room temperature for 2 hours, the low boiling substances were removed under reduced pressure. To the residue was added potassium carbonate (2.5 g, 18.1 mmol), dimethyl sulfate (2.3 g, 18.2 mmol), and DMF (5 ml) under ice-cooling. After stirring at room temperature for 3 hours, the mixture was distilled under reduced pressure to remove low boiling substances. The residue was diluted with ethyl acetate, successively washed with water, and saturated brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was chromatographed over silica gel (eluent; ethyl acetate/n-hexane=1:1) to obtain (E)-methyl 2-(4-benzyloxy-1,3-dimethylpyrazol-5-yl)-3-methoxyacrylate (compound No. 1 in the Table 1) as a clear oil (2.1 g, 73%). Corresponding compound in Z-form (compound No. 2 in the Table 1) was also produced by the above reaction and recovered from the column.

Provenance & Evidence