Butylamine → N,N-dibutyl-4-chloro-5-methyl-1H-pyrazole-3-carboxamide

HRID 528788

Reaction equation

[CH2:1]([NH2:5])[CH2:2][CH2:3][CH3:4].[Li][CH2:7][CH2:8][CH2:9][CH3:10].[Cl:11][C:12]1[C:13]([C:18]([O:20]CC)=O)=[N:14][NH:15][C:16]=1[CH3:17]>C1COCC1>[CH2:1]([N:5]([CH2:7][CH2:8][CH2:9][CH3:10])[C:18]([C:13]1[C:12]([Cl:11])=[C:16]([CH3:17])[NH:15][N:14]=1)=[O:20])[CH2:2][CH2:3][CH3:4]

Participants

Conditions

Temperature: -78 °C

Procedure

To a solution of n-butylamine (900 μL, 5.30 mmol) in THF (4.0 mL) was added n-BuLi (5.0 mL, 7.95 mmol, 2.5M solution in hexanes) at −78° C. After stirring at −78° C. for 30 min, a solution of ethyl 4-chloro-5-methyl-1H-pyrazole-3-carboxylate (500 mg, 2.65 mmol) in 2.0 mL of THF was added dropwise via syringe. The reaction mixture was allowed to warm to room temperature overnight and quenched with sat. aq. NH4Cl solution. The aqueous layer was extracted with CH2Cl2 (3×), and the combined organic extracts were dried over Na2SO4, filtered and concentrated in vacuo to give a crude oil. Purification using flash column chromatography (gradient from 0% to 7% MeOH/CH2Cl2) provided the title compound (589 mg, 82%) as a colorless oil. 1H NMR (CD3OD) δ 3.51 (t, J=7.4 Hz, 2H), 3.38-3.32 (m, 2H), 1.68-1.62 (m, 2H), 1.56-1.50 (m, 2H), 1.45-1.38 (m, 2H), 1.22-1.15 (m, 2H) 0.98 (t, J=7.4 Hz, 3H), 0.81 (t, J=7.4 Hz, 3H); MS(ESI+) m/z 272.1 (M+H)+.

Workup

temperatureto warm to room temperature overnight
customquenched with sat. aq. NH4Cl solution
extractionThe aqueous layer was extracted with CH2Cl2 (3×)
dry with materialthe combined organic extracts were dried over Na2SO4
filtrationfiltered
concentrationconcentrated in vacuo
customto give a crude oil
customPurification

Sources & evidence

ORD record: ord-24a83f24190a4d58aa6016eab1c3e639
Source dataset: uspto-grants-2016_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09346795B2

Linked notes

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