Sodium Hydroxide → 5-(3-methylbutyl)-1H-pyrazole-3-carboxylic Acid

Participants

Reaction Steps

Freshly prepared aq. NaOH (10 M in H2O, 80.85 mmol) was added to a stirring, room temperature solution of 47 (3.40 g, 16.17 mmol) in MeOH (40.4 mL, 0.4 M) under N2. The reaction was then heated to reflux until the reaction was judged complete by HPLC (6 min): The reaction was concentrated and then dissolved in 14 mL H2O. 10% aq. HCl was added dropwise until the pH=2. The white solid that precipitated from the reaction was filtered off and washed with cold H2O. The solid was dried under vacuum overnight to obtain 2.8753 g (97.6%) of 48. (Note: An undesired impurity has a retention time of 9.522 min by HPLC.) 1H (CDCl3, 400 MHz): δ 6.61(1H, s), 2.70 (2H, t, J=7.8Hz), 1.63-1.51 (3H, m), 0.94 (6H, d, J=6.3 Hz) ppm. 13C (CDCl3, 100 MHz): δ 164.35, 149.48, 143.00, 107.34 28.71, 24.69, 22.65 ppm. DEPT (CDCl3, 100 MHz): CH3 carbons: 22.65; CH2 carbons: 39.35, 24.69; CH carbons: 107.34, 28.71 ppm. HPLC: 9.522 min.

Provenance & Evidence