Lithium Hydroxide → 3-tert-butyl-1-(2-(dimethylamino)ethyl)-1H-pyrazole-5-carboxylic acid
Reaction equation
[C:1]([C:5]1[CH:9]=[C:8]([C:10]([O:12]CC)=[O:11])[N:7]([CH2:15][CH2:16][N:17]([CH3:19])[CH3:18])[N:6]=1)([CH3:4])([CH3:3])[CH3:2].[Li+].[OH-]>C1COCC1>[C:1]([C:5]1[CH:9]=[C:8]([C:10]([OH:12])=[O:11])[N:7]([CH2:15][CH2:16][N:17]([CH3:19])[CH3:18])[N:6]=1)([CH3:4])([CH3:2])[CH3:3]Participants
4
Procedure
To a solution of ethyl 3-tert-butyl-1-(2-(dimethylamino)ethyl)-1H-pyrazole-5-carboxylate (0.47 g, 1.8 mmol) in THF (10 mL) was added aqueous LiOH (0.22 g, 5.3 mmol, 5 mL) and mixture was stirred for 16 h at RT. Solvents were removed, the thick liquid was diluted with water (5 mL) and acidified with 50% aq. acetic acid solution to pH 5-6. The product was extracted with EtOAc (2×50 ml) and the combined organics were washed with brine, dried (Na2SO4) and concentrated in vacuo to afford 3-tert-butyl-1-(2-(dimethylamino)ethyl)-1H-pyrazole-5-carboxylic acid as a pasty mass (0.12 g, 29% yield). 1H NMR (400 MHz, DMSO-d6): δ 6.56 (s, 1H), 4.66 (t, J=6.0 Hz, 2H), 3.17 (t, J=6.0 Hz, 2H), 2.53 (s, 6H), 1.17 (s, 9H); MS (ESI) m/z: 240.3 (M+H+).