反应详情

A solution of 2-formyl-3-oxo-propionic acid ethyl ester (S. H. Bertz et al., J. Org. Chem., 1982, 47, 2216) (1.44 g, 10 mmol) in EtOH (10 mL) was cooled in an ice bath. A slurry of 3-hydrazino-4-methyl-benzoic acid hydrochloride (2.02 g, 10 mmol) in EtOH (50 mL) was added and the reaction was stirred overnight. The EtOH was removed under reduced pressure and the residue partitioned between water and CH2Cl2. The layers were separated and the organic layer washed with brine. The organic layer was dried over Na2SO4, filtered, and concentrated. Hexanes were added and the solution concentrated. The resulting solid was collected by vacuum filtration, washed with hexanes and dried under vacuum to provide 1-(5-carboxy-2-methyl-phenyl)-1H-pyrazole-4-carboxylic acid ethyl ester (1.86 g, 68%) as a yellow solid: ESI MS m/z 275 [C14H14N2O4+H]+.

1. customThe EtOH was removed under reduced pressure
2. customthe residue partitioned between water and CH2Cl2
3. customThe layers were separated
4. washthe organic layer washed with brine
5. dry with materialThe organic layer was dried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. additionHexanes were added
9. concentrationthe solution concentrated
10. filtrationThe resulting solid was collected by vacuum filtration
11. washwashed with hexanes
12. customdried under vacuum