Sodium Hydroxide → 5-Methyl-1-phenethylpyrazole-3-carboxylic acid

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Reaction Steps

Ethyl 5-methyl-1-phenethylpyrazole-3-carboxylate (3.84 g, 14.9 mM) in ethanol (30 ml) with sodium hydroxide (0.6 g 14.9 mM) was stirred at room temperature for 3 days. The mixture was then diluted with ethyl acetate and water and the layers separated. The organic phase was further extracted with water. The combined aqueous extracts were acidified to pH 2.0 with 5M hydrochloric acid and extracted with dichloromethane. The organic extracts were dried (MgSO4) and evaporated to give the title compound (3.24 g, 95%); νmax (CH2Cl2) 1759 and 1699 cm-1 ; δH (CDCl3) 1.91 (3H, s), 3.16 (2H, t, J7 Hz), 4.31 (2H, t, J7 Hz), 6.54 (1H, s), 6.98-7.10 (2H, m), and 7.20-7.37 (3H, m).

Provenance & Evidence