反应详情

温度

60 °C

Under an atmosphere of argon, methylhydrazine (1.15 g, 25 mmol) and HCl (36.5% in water, 2.5 ml) were added to a solution of 2-dimethylaminomethylene-3-oxo-succinic acid diethyl ester (6.07 g, 25 mmol, obtained by the method of Hanzlowsky et al., J. Heterocyclic Chem. 2003, 40(3), 487-498) in ethanol (200 ml). The mixture was heated to 60° C. until HPLC analysis indicated the disappearance of the starting material (2 h). The solvent was evaporated, and the residue was taken up in dichloromethane and washed (water). The organic layer was dried (Na2SO4), the solvent was evaporated and the title compound (2.06 mg, 36%) was isolated from the mixture by column chromatography (silica gel, heptane:ethyl acetate=100:0-60:40). (The regioisomeric 1-methyl-1H-pyrazole-3,4-dicarboxylic acid diethyl ester can also be isolated, and can be distinguished from the desired product by NOE-1H-NMR.) MS (m/e)=227.2 [M+H+].

1. customobtained by the method of Hanzlowsky et al., J
2. customthe disappearance of the starting material (2 h)
3. customThe solvent was evaporated
4. washwashed (water)
5. dry with materialThe organic layer was dried (Na2SO4)
6. customthe solvent was evaporated