Sodium Hydroxide → 5-Ethyl-1-(4-methylbenzyl)-1H-pyrazole-3-carboxylic acid

HRID 2400531Notes

Reaction equation

[CH2:1]([C:3]1[N:7]([CH2:8][C:9]2[CH:14]=[CH:13][C:12]([CH3:15])=[CH:11][CH:10]=2)[N:6]=[C:5]([C:16]([O:18]CC)=[O:17])[CH:4]=1)[CH3:2].[OH-].[Na+]>C(O)C>[CH2:1]([C:3]1[N:7]([CH2:8][C:9]2[CH:14]=[CH:13][C:12]([CH3:15])=[CH:11][CH:10]=2)[N:6]=[C:5]([C:16]([OH:18])=[O:17])[CH:4]=1)[CH3:2]

Participants

Conditions

Temperature: 70 °C

Procedure

To a solution of ethyl 5-ethyl-1-(4-methylbenzyl)-1H-pyrazole-3-carboxylate (Step 2, 1.85 g, 6.79 mmol) in ethanol (43 mL) was added NaOH (1N aq., 13.6 mL, 13.6 mmol), and the mixture was heated at 70° C. for 3 h. The organic solvent was evaporated under vacuum and the residue was acidified with HCl (3N aq.) at 0° C. until a white solid completely precipitated from solution. The solid was filtered, washed with water, and was dried in a vacuum oven to afford the title compound as a white solid (1.53 g, 92%): 1H NMR (500 MHz, CDCl3) 7.07 (d, 2H), 6.94 (d, 2H), 6.63 (s, 1H), 5.23 (s, 2H), 2.47 (quart, 2H), 2.30 (s, 3H), 1.17 (t, 3H); ES-MS m/z 245 (MH)+, 262 (M+NH4)+; HPLC RT (Method I) 4.12 min.

Workup

customThe organic solvent was evaporated under vacuum
customwas acidified with HCl (3N aq.) at 0° C. until a white solid
customcompletely precipitated from solution
filtrationThe solid was filtered
washwashed with water
customwas dried in a vacuum oven

Sources & evidence

ORD record: ord-8dec088247a241929a0974f0ce2f087e
Source dataset: uspto-grants-2014_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08796253B2

Reaction notes

Loading…