ethyl 2-(1,3,5-trimethyl-1H-pyrazol-4-yl)acetate → (1,3,5-Trimethyl-1H-pyrazol-4-yl)-acetaldehyde

HRID 220458Notes

Reaction equation

HRID 220458 reaction equation
C([O:3][C:4](=O)[CH2:5][C:6]1[C:7]([CH3:13])=[N:8][N:9]([CH3:12])[C:10]=1[CH3:11])C.[H-].C([Al+]CC(C)C)C(C)C>O1CCCC1>[CH3:12][N:9]1[C:10]([CH3:11])=[C:6]([CH2:5][CH:4]=[O:3])[C:7]([CH3:13])=[N:8]1

Participants

4

Reactant 2

HCID 16394807ethyl 2-(1,3,5-trimethyl-1H-pyrazol-4-yl)acetateHCID 21225700Diisobutylaluminumhydride

Product 1

HCID 64868769(1,3,5-Trimethyl-1H-pyrazol-4-yl)-acetaldehyde

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

Dissolve (1,3,5-trimethyl-1H-pyrazol-4-yl)-acetic acid ethyl ester (2.8 g, 14.3 mmol) in tetrahydrofuran (200 mL) and cool to −78° C. Add diisobutylaluminum hydride (42.8 mL, 42.8 mmol, 1 M in toluene) dropwise over 30 min. Stir an additional 2 hr. at −78° C. Partition between saturated aqueous potassium sodium tartrate solution (150 mL) and ethyl acetate (500 mL) and stir for 16 hr. at room temperature. Separate organic layer, dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 1:1 hexanes:ethyl acetate), to give the title preparation (0.26 g, 12%). 1H NMR (CDCl3) δ 9.54 (t, 1H), 3.71 (s, 3H), 3.38 (d, 2H), 2.15 (s, 3H), 2.14 (s, 3H).

Workup

  1. customat −78° C
  2. customPartition between saturated aqueous potassium sodium tartrate solution (150 mL) and ethyl acetate (500 mL)
  3. stirringstir for 16 hr
  4. customat room temperature
  5. dry with materialSeparate organic layer, dry (sodium sulfate)
  6. filtrationfilter
  7. concentrationconcentrate
  8. custompurify
  9. wash(silica gel chromatography, eluting with 1:1 hexanes:ethyl acetate)
  10. customto give the title
  11. custompreparation (0.26 g, 12%)

Sources & evidence

ORD record
ord-45c841a68ae84b13a5aa9154cc0410ec
Source dataset
uspto-grants-2012_06
Patent number
US08202873B2

Reaction notes

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