Potassium bis(trimethylsilyl)amide → Ethyl 1-((1H-indol-3-yl)methyl)-3-isopropyl-1H-pyrazole-5-carboxylate

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Reaction Steps

To an oven dried flask cooled under argon equipped with a stir bar was added ethyl 3-isopropyl-1H-pyrazole-5-carboxylate (0.044 grams, 0.24 mmol, 0.1 in anhydrous 1,4 dioxane). While stirring at room temperature KHMDS (0.3 mL, 0.261 mmol, 0.87 M in toluene) was added. After stirring for 45 minutes, a solution of (1-benzoyl-1H-indol-3-yl)methyl benzoate (0.02 grams, 0.056 mmol, in 1.0 mL of anhydrous 1,4 dioxane) was added and the reaction mixture stirred over night. The next day, the reaction was quenched with 0.1M HCl and the organic material extracted with ethyl acetate. The aqueous solution was then salted out using sodium chloride and washed twice with ethyl acetate. The combined organic material was then dried with sodium sulfate, filtered, and concentrated. Purification using a Teledyne ISCO chromatography on silica gel (hexanes/ethyl acetate gradient) followed by a Teledyne ISCO chromatography using C18 reverse phase (water with 0.1% formic acid, acetonitrile gradient) afforded the desired compound. Yield, 63%. 1H NMR δ 8.29 (bs, 1H), 7.58 (d, 1H), 7.36 (d, 1H), 7.20 (t, 1H), 7.11 (t, 1H), 6.96 (s, 1H), 6.62 (s, 1H), 5.58 (s, 2H), 4.41 (q, 2H), 3.03 (m, 1H), 1.39 (t, 3H), 1.16 (d, 6H). Calculated mass for C18H21N3O2, 311.16. Observed 334.1 (M+1).

Provenance & Evidence