Diisobutylaluminumhydride → (3-Isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetaldehyde

HRID 220474Notes

Reaction equation

C([O:3][C:4](=O)[CH2:5][C:6]1[C:7]([CH2:18][CH:19]([CH3:21])[CH3:20])=[N:8][N:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][N:13]=2)[C:10]=1[CH3:11])C.[H-].C([Al+]CC(C)C)C(C)C>O1CCCC1>[CH2:18]([C:7]1[C:6]([CH2:5][CH:4]=[O:3])=[C:10]([CH3:11])[N:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][N:13]=2)[N:8]=1)[CH:19]([CH3:21])[CH3:20]

Participants

Conditions

Temperature: -78 °C

Procedure

Dissolve (3-isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetic acid ethyl ester (3.35 g, 11.11 mmol) in tetrahydrofuran (50 mL) and cool to −78° C. Add diisobutylaluminum hydride (33.3 mL, 33.3 mmol, 1 M in toluene) dropwise. Continue stirring at −78° C. for 6 hr. Quench with saturated aqueous potassium sodium tartrate solution (50 mL) and warm to room temperature over 16 hr. Extract with ethyl acetate (2×100 mL). Combine organic layers, dry (sodium sulfate), filter and concentrate. Purify using silica gel chromatography, eluting with 90:10 hexanes:ethyl acetate, to give the title preparation (1.60 g, 56%). 1H-NMR (400 MHz, CDCl3) δ 9.62 (t, 1H), 8.39 (m, 1H), 7.77 (m, 2H), 7.15 (m, 1H), 3.45 (d, 2H), 2.96 (d, 2H), 2.22 (s, 3H), 1.80 (m, 1H), 0.81 (d, 6H).

Workup

customQuench with saturated aqueous potassium sodium tartrate solution (50 mL)
temperaturewarm to room temperature over 16 hr
extractionExtract with ethyl acetate (2×100 mL)
dry with materialCombine organic layers, dry (sodium sulfate)
filtrationfilter
concentrationconcentrate
customPurify
washeluting with 90:10 hexanes
customethyl acetate, to give the title
custompreparation (1.60 g, 56%)

Sources & evidence

ORD record: ord-743728ee57c349519cf0f0b7e0f8dbc9
Source dataset: uspto-grants-2012_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08202873B2

Reaction notes

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