2-Hydrazinopyridine → (3-isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetic acid ethyl ester

HRID 220473Notes

Reaction equation

HRID 220473 reaction equation
[CH2:1]([O:3][C:4](=[O:16])[CH2:5][CH:6]([C:13](=O)[CH3:14])[C:7](=O)[CH2:8][CH:9]([CH3:11])[CH3:10])[CH3:2].[N:17]1[CH:22]=[CH:21][CH:20]=[CH:19][C:18]=1[NH:23][NH2:24]>C(O)(=O)C>[CH2:1]([O:3][C:4](=[O:16])[CH2:5][C:6]1[C:7]([CH2:8][CH:9]([CH3:11])[CH3:10])=[N:24][N:23]([C:18]2[CH:19]=[CH:20][CH:21]=[CH:22][N:17]=2)[C:13]=1[CH3:14])[CH3:2]

Participants

4

Reactant 2

HCID 786452-HydrazinopyridineHCID 866416513-Acetyl-6-methyl-4-oxoheptanoic acid ethyl ester

Product 1

HCID 68596057(3-isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetic acid ethyl esterYield 85%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Combine 3-acetyl-6-methyl-4-oxoheptanoic acid ethyl ester (3.0 g, 13.1 mmol) and pyridin-2-yl-hydrazine (1.72 g, 15.72 mmol) in glacial acetic acid (25 mL) and stir at room temperature for 68 hr. Concentrate to an oil and partition the residue between ethyl acetate (150 mL) and saturated aqueous sodium bicarbonate solution (50 mL). Separate the organic layer, dry (sodium sulfate), filter and concentrate. Purify using silica gel chromatography, eluting with 90:10 hexanes:ethyl acetate, to give (3-isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetic acid ethyl ester (3.35 g, 85%). 1H-NMR (400 MHz, CDCl3) δ 8.38 (m, 1H), 7.77 (m, 2H), 7.13 (m, 1H), 4.12 (q, 2H), 3.41 (s, 2H), 2.98 (d, 2H), 2.27 (s, 3H), 1.82 (m, 1H), 1.22 (t, 3H), 0.80 (d, 6H).

Workup

  1. concentrationConcentrate to an oil
  2. custompartition the residue between ethyl acetate (150 mL) and saturated aqueous sodium bicarbonate solution (50 mL)
  3. customSeparate the organic layer
  4. dry with materialdry (sodium sulfate)
  5. filtrationfilter
  6. concentrationconcentrate
  7. customPurify
  8. washeluting with 90:10 hexanes

Sources & evidence

ORD record
ord-c5ffa96f4e604242bc23e39206e71cd6
Source dataset
uspto-grants-2012_06
Patent number
US08202873B2

Reaction notes

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