HCID 22101094, compound → HCID 178469935, compound

Participants

Reaction Steps

To a solution of 3-amino-4-ethoxycarbonylpyrazole (1.0 g) in THF (10 ml), was added di-tert-butyl dicarbonate (2.2 g), and the mixture was stirred overnight at room temperature. The reaction mixture was evaporated under reduced pressure followed by silica-gel column chromatography (toluene/ethyl acetate=15/1) to give 3-amino-1(tert-butoxycarbonyl)-4-ethoxycarbonylpyrazole (0.59 g). This intermediate was derived to N-phenyl-N'-(1-tert-butoxycarbonyl-4-ethoxycarbonylpyrazol-3-yl)urea by the similar method to Reference Example 1 (yield 75%). N-phenyl-N'-(1-tertbutoxycarbonyl-4-ethoxycarbonylpyrazol-3-yl)urea (0.5 g) was dissolved in a solution of 10% trifluoroacetic acid in dichloromethane (7 ml), and the resulted solution was stirred overnight at room temperature. The reaction mixture was evaporated under reduced pressure followed by addition of ether to give the title compound (0.304 g, yield 83%).

Provenance & Evidence