p-Toluenesulfonic acid → 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole-3-carboxylic acid

HRID 2367697Notes

Reaction equation

[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][N:6]=[C:5]2[C:11]([OH:13])=[O:12].[O:14]1[CH:19]=[CH:18][CH2:17][CH2:16][CH2:15]1.CC1C=CC(S(O)(=O)=O)=CC=1>C1COCC1>[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[N:7]([CH:15]1[CH2:16][CH2:17][CH2:18][CH2:19][O:14]1)[N:6]=[C:5]2[C:11]([OH:13])=[O:12]

Participants

Conditions

Temperature: 60 °C

Procedure

To a solution of 5-bromo-1H-indazole-3-carboxylic acid (CXV) (59.8 g, 248 mmol) in THF (800 mL) under argon was added 3,4 dihydro-2H-pyran (50.6 mL, 558 mmol) and p-TsOH (4.72 g, 24.8 mmol). The reaction was heated to reflux at 60° C. for 16 h. An additional portion of p-TsOH (0.025 eq) and 3,4 dihydro-2H-pyran (0.56 eq) was added and the reflux continued for 5 h. The solution was concentrated under vacuum. EtOAc was added to the residue and the suspension was filtered and dried under high vacuum overnight to produce 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole-3-carboxylic acid (CXVIII) as a white solid (49.07 g, 150.9 mmol, 60.8% yield). ESIMS found for C13H13BrN2O3 m/z 326.3 (M+H).

Workup

temperatureThe reaction was heated
concentrationThe solution was concentrated under vacuum
additionEtOAc was added to the residue
filtrationthe suspension was filtered
customdried under high vacuum overnight

Sources & evidence

ORD record: ord-4dd9615f77334af897f54dd3fd46a5da
Source dataset: uspto-grants-2014_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08697887B2

Reaction notes

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