Cornforth reagent → Toluene-4-sulfonic acid 5-acetyl-1H-pyrazol-3-yl ester

HRID 985438Notes

Reaction equation

HRID 985438 reaction equation
[OH:1][C@H:2]([C:4]1[NH:8][N:7]=[C:6]([O:9][S:10]([C:13]2[CH:18]=[CH:17][C:16]([CH3:19])=[CH:15][CH:14]=2)(=[O:12])=[O:11])[CH:5]=1)[CH3:3].[Cr](O[Cr]([O-])(=O)=O)([O-])(=O)=O.[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1>ClCCl>[C:2]([C:4]1[NH:8][N:7]=[C:6]([O:9][S:10]([C:13]2[CH:18]=[CH:17][C:16]([CH3:19])=[CH:15][CH:14]=2)(=[O:12])=[O:11])[CH:5]=1)(=[O:1])[CH3:3]

Participants

4

Reactant 2

HCID 2724130Cornforth reagentHCID 87418248toluene-4-sulfonic acid 5-[(S)-l-hydroxyethyl]-1H-pyrazol-3-yl ester

Product 1

HCID 87418291Toluene-4-sulfonic acid 5-acetyl-1H-pyrazol-3-yl esterYield 85%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To toluene-4-sulfonic acid 5-[(S)-1-hydroxyethyl]-1H-pyrazol-3-yl ester (6.09 g, 21.6 mmol) in anhydrous dichloromethane (180 ml) was added pyridinium dichromate (9.74 g, 25.9 mmol) and the resulting slurry was stirred at room temperature for 17.6 h. The mixture was poured directly onto a column of silica gel, which was eluted with ethyl acetate to yield 5.13 g (85%) of the title compound as a whitish solid: 1H NMR (360 MHz, DMSO-d6) δ 2.43 (3H, s), 2.45 (3H, s), 6.78 (1H, s), 7.49 (2H, d, J=8.2 Hz), 7.80 (2H, d, J=8.3 Hz), 13.72 (1H, s); MS (ES+) m/e 281 [M+H]+.

Workup

  1. additionThe mixture was poured directly onto a column of silica gel, which
  2. washwas eluted with ethyl acetate

Sources & evidence

ORD record
ord-f7d9f9776713465383fb12c31cc60c67
Source dataset
uspto-grants-2005_03
Patent number
US06872720B2

Reaction notes

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