Hydrochloric Acid → Methyl 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetate

HRID 2425546Notes

Reaction equation

HRID 2425546 reaction equation
C(O[CH:4]=[C:5]([C:9](=[O:11])[CH3:10])[C:6](=O)[CH3:7])C.Cl.[NH:13]([CH2:15][C:16]([O:18][CH2:19]C)=[O:17])[NH2:14].Cl>CO>[C:9]([C:5]1[CH:4]=[N:14][N:13]([CH2:15][C:16]([O:18][CH3:19])=[O:17])[C:6]=1[CH3:7])(=[O:11])[CH3:10]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 2404183-(Ethoxymethylene)pentane-2,4-dioneHCID 11593468Acetic acid, 2-hydrazinyl-, ethyl ester, hydrochloride (1:1)

Product 1

HCID 67181907Methyl 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetateYield 51%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent2×

Procedure

To a solution of 3-(ethoxymethylene)pentane-2,4-dione (Perkin 1. 2000, 1455-1460, 1.95 g, 12.5 mmol) in MeOH (33 mL) was added a solution of ethyl hydrazinoacetate hydrochloride (2.09 g, 13.5 mmol) and conc.HCl (2.6 ml) in MeOH (10 ml) (pre-cooled to 0° C.) dropwise at −15° C. The resulting mixture was then stirred for 24 hours at room temperature. After removal of the solvent at room temperature, the residue was basified with 2N NaOH aq, and the aqueous layer was extracted several times with EtOAc. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo. The aqueous layer was acidified to pH 1 with 2N HCl aq. and extracted with EtOAc 6 times. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo to give the crude 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetic acid as a mixture of regioisomers (1.17 g, <51% yield). 1H NMR (300 MHz, DMSO-d6) δ 2.37 (3H, s), 2.43 (3H, s), 4.99 (2H, s), 7.81 (1H, s), 13.2 (1H, brs).

Workup

  1. customdropwise at −15° C
  2. customAfter removal of the solvent at room temperature
  3. extractionthe aqueous layer was extracted several times with EtOAc
  4. dry with materialThe combined organic extracts were dried over Na2SO4
  5. concentrationconcentrated in vacuo
  6. extractionextracted with EtOAc 6 times
  7. dry with materialThe combined organic extracts were dried over Na2SO4
  8. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-d43b84bb2a0241498bdceb2d977672b4
Source dataset
uspto-grants-2011_06
Patent number
US07964732B2

Reaction notes

Loading…