Hydrochloric Acid → 3-Chloro-1-(pyridine-3-yl)-1H-pyrazole-5-carboxylic acid hydrochloride

HRID 517367Notes

Reaction equation

[Cl:1][C:2]1[CH:6]=[C:5]([C:7]([O:9]CC)=[O:8])[N:4]([C:12]2[CH:13]=[N:14][CH:15]=[CH:16][CH:17]=2)[N:3]=1.Cl>O1CCOCC1>[ClH:1].[Cl:1][C:2]1[CH:6]=[C:5]([C:7]([OH:9])=[O:8])[N:4]([C:12]2[CH:13]=[N:14][CH:15]=[CH:16][CH:17]=2)[N:3]=1

Participants

Conditions

Temperature: 90 °C

Procedure

A 3-neck round bottomed flask (100 mL) was charged with ethyl 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylate (0.200 g, 0.795 mmol) and hydrochloric acid (37%, 4 mL). The reaction was heated at 90° C. for 18 hours and allowed to cool to 20° C. Dioxane (5 mL) was added to the resulting suspension and was concentrated to dryness. Dioxane (5 mL) was added and the suspension was concentrated again to afford a white solid. Dioxane (5 mL) was added and the resulting suspension was stirred for 1 hour at 20° C. The solid was filtered and the solid was rinsed with dioxane (2 mL). The filter cake was dried under vacuum at 20° C. to afford the title compound as a white solid (0.218 g, 100%): 1H NMR (400 MHz, DMSO-d6) δ 9.05 (dd, J=2.5, 0.7 Hz, 1H), 8.84 (dd, J=5.3, 1.4 Hz, 1H), 8.41 (ddd, J=8.3, 2.5, 1.4 Hz, 1H), 7.88 (ddd, J=8.3, 5.2, 0.7 Hz, 1H), 7.26 (s, 1H); 13C NMR (101 MHz, DMSO-d6) δ 158.71, 146.00, 143.44, 140.36, 137.76, 137.00, 136.83, 125.19, 111.71.

Workup

temperatureto cool to 20° C
concentrationwas concentrated to dryness
additionDioxane (5 mL) was added
concentrationthe suspension was concentrated again
customto afford a white solid
filtrationThe solid was filtered
washthe solid was rinsed with dioxane (2 mL)
customThe filter cake was dried under vacuum at 20° C.

Sources & evidence

ORD record: ord-449669b5fd4349cc9c8204d6d515f246
Source dataset: uspto-grants-2015_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09115115B1

Reaction notes

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