Ethyl 5-methyl-2,4-dioxohexanoate → ethyl 1-(2,4-dimethoxypyrimidin-5-yl)-5-isopropyl-1H-pyrazole-3-carboxylate

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Reaction Conditions

Reaction Steps

5-hydrazinyl-2,4-dimethoxypyrimidine (Step 46.8) (140 g, 823 mmol) was dissolved in toluene (3 L) under nitrogen atmosphere and ethyl-2,4-dioxo-5-methylhexanoate (230 g, 1234 mmol) was added dropwise over 15 min. The reaction mixture was heated up and stirred at 110° C. for 1 hr. The brown solution was quenched with saturated aq. NaHCO3 solution (2 L) and extracted with EtOAc (2×2 L). The combined organic layers were washed with brine (2 L), dried over Na2SO4, filtered and concentrated under reduced pressure. The crude material was stirred in hexane (1 L) at RT and the resulting suspension was filtrated off and dried to afford the title product (193 g, 596 mmol, 72% yield) as white crystals. tR: 1.01 min (LC-MS 1); ESI-MS: 321 [M+H]+ (LC-MS 1).

Provenance & Evidence