Hydrochloric Acid → 4,5-Diethyl 1-methyl-1H-pyrazole-4,5-dicarboxylate

HRID 1958319Notes

Reaction equation

[CH3:1][NH:2]N.Cl.[CH2:5]([O:7][C:8](=[O:21])[C:9](=[CH:17][N:18](C)C)[C:10](=O)[C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH3:6]>C(O)C>[CH2:14]([O:13][C:11]([C:10]1[N:2]([CH3:1])[N:18]=[CH:17][C:9]=1[C:8]([O:7][CH2:5][CH3:6])=[O:21])=[O:12])[CH3:15]

Participants

Conditions

Temperature: 60 °C

Procedure

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+].

Workup

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

Sources & evidence

ORD record: ord-d2a4c38702a84a03aaa9729a4d5f3d96
Source dataset: uspto-grants-2013_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08410117B2

Reaction notes

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