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

HRID 220457

Reaction equation

HRID 220457 reaction equation
[CH2:1]([O:3][C:4](=[O:13])[CH2:5][CH:6]([C:10](=O)[CH3:11])[C:7](=O)[CH3:8])[CH3:2].[CH3:14][NH:15][NH2:16]>C(O)(=O)C>[CH2:1]([O:3][C:4](=[O:13])[CH2:5][C:6]1[C:10]([CH3:11])=[N:16][N:15]([CH3:14])[C:7]=1[CH3:8])[CH3:2]

Participants

4

Reactant 2

HCID 6061MethylhydrazineHCID 87820Ethyl 3-acetyl-4-oxopentanoate

Product 1

HCID 16394807ethyl 2-(1,3,5-trimethyl-1H-pyrazol-4-yl)acetateYield 73.2%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Dissolve 3-acetyl-4-oxopentanoic acid ethyl ester (3.35 g, 19.5 mmol) in glacial acetic acid (20 mL) and add methylhydrazine (1.13 mL, 21.4 mmol) dropwise. Stir the resulting mixture at room temperature for 16 hr. Concentrate and partition the residue between ethyl acetate (100 mL) and saturated aqueous sodium bicarbonate solution (50 mL). Separate organic layer, dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 7:3 hexanes:ethyl acetate) to give (1,3,5-trimethyl-1H-pyrazol-4-yl)-acetic acid ethyl ester (2.8 g, 73%) as an oil. 1H NMR (CDCl3) δ 4.08 (q, 2H), 3.67 (s, 3H), 3.29 (s, 2H), 2.18 (s, 6H), 1.21 (t, 3H).

Workup

  1. concentrationConcentrate
  2. custompartition the residue between ethyl acetate (100 mL) and saturated aqueous sodium bicarbonate solution (50 mL)
  3. dry with materialSeparate organic layer, dry (sodium sulfate)
  4. filtrationfilter
  5. concentrationconcentrate
  6. custompurify
  7. wash(silica gel chromatography, eluting with 7:3 hexanes:ethyl acetate)

Sources & evidence

ORD record
ord-2d95a319eeab4885851635057c0e2465
Source dataset
uspto-grants-2012_06
Patent number
US08202873B2

Linked notes

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