Methylhydrazine → ethyl 3-(tert-butyl)-1-methyl-1H-pyrazole-5-carboxylate

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Reaction Steps

Ethyl 5,5-dimethyl-2,4-dioxo-hexanoate (1.02 g, 5.09 mmol) was dissolved in absolute EtOH (20 mL). CH3NHNH2 (0.270 mL, 5.09 mmol) was added dropwise and the resulting mixture was stirred at room temperature for 2 h. The resulting mixture was warmed to 80° C. for 4 h, and then cooled to room temperature. The solvent was removed under reduced pressure, and the resulting residue was chromatographed using a 70-g pre-packed SiO2 column eluting with 1:19 EtOAc-hexanes to yield the title compound as a colorless oil. 1H-NMR (400 MHz, CDCl3) δ: 6.68 (s, 1H), 4.33 (q, J=7.2 Hz, 2H), 4.12 (s, 3H), 1.38 (t, J=7.1 Hz, 3H), 1.30 (s, 9H).

Provenance & Evidence