Methanol → methyl 3-(1-methyl-1H-pyrazol-4-yl)prop-2-enoate
Reaction equation
[CH3:1][N:2]1[CH:6]=[C:5](/[CH:7]=[CH:8]/[C:9]([OH:11])=[O:10])[CH:4]=[N:3]1.OS(O)(=O)=O.[OH-].[Na+].[CH3:19]O>>[CH3:1][N:2]1[CH:6]=[C:5](/[CH:7]=[CH:8]/[C:9]([O:11][CH3:19])=[O:10])[CH:4]=[N:3]1Participants
5
Procedure
(2E)-3-(1-Methyl-1H-pyrazol-4-yl)-2-propenoic acid (7.5 g, 49.3 mmol) was added to a solution of H2SO4 (1.760 ml, 33.0 mmol) in methanol (40 ml), and the resultant mixture was refluxed for 4 h. It was cooled to room temperature, then poured into ice. The acid was neutralized with aqueous sodium hydroxide and extracted with DCM (80 ml×2). The organic phases were collected and combined, dried over MgSO4, and concentrated. The residue was washed with petroleum ether and concentrated to give the title compound (7 g, 71.8% yield). LCMS: rt=1.13 min, [M+H+]=167