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

HRID 2425547Notes

Reaction equation

HRID 2425547 reaction equation
[C:1]([C:4]1[CH:5]=[N:6][N:7]([CH2:10][C:11]([OH:13])=[O:12])[C:8]=1[CH3:9])(=[O:3])[CH3:2].[C:14]1(C)C=CC=CC=1.C[Si](C=[N+]=[N-])(C)C.CCOCC>CO>[C:1]([C:4]1[CH:5]=[N:6][N:7]([CH2:10][C:11]([O:13][CH3:14])=[O:12])[C:8]=1[CH3:9])(=[O:3])[CH3:2]

Participants

6

Reactant 4

HCID 1140TolueneHCID 3283Diethyl EtherHCID 167693TrimethylsilyldiazomethaneHCID 632769652-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetic acid

Product 1

HCID 67181907Methyl 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetateYield 99%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a solution of 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetic acid (1.17 g, 6.42 mmol, as a mixture of regioisomers from the previous step) in MeOH (8.8 ml)-Toluene (30.6 ml) was added a 2 M solution of (trimethylsilyl)diazomethane in ether (4.8 ml, 9.6 mmol) dropwise at 0° C. The resulting solution was allowed to warm to rt and stirred for 120 min. The reaction was quenched by addition of AcOH (3 ml) and the solvent was concentrated in vacuo. The crude product was purified by silica gel column chromatography (CH2Cl2:MeOH=30:1) to give the desired product along with a mixture of regioisomers (>99% yield). 1H NMR (270 MHz, CDCl3) δ 2.45 (3H, s), 2.53 (3H, s), 3.79 (3H, s), 4.90 (2H, s), 7.88 (1H, s).

Workup

  1. customThe reaction was quenched by addition of AcOH (3 ml)
  2. concentrationthe solvent was concentrated in vacuo
  3. customThe crude product was purified by silica gel column chromatography (CH2Cl2:MeOH=30:1)

Sources & evidence

ORD record
ord-482840abe9c74daa8b9da94f887c52c0
Source dataset
uspto-grants-2011_06
Patent number
US07964732B2

Reaction notes

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