Tetrahydrofuran → 1-Methyl-3-bromo-5-(5-methylpyridin-2-yl)pyrazole

HRID 1823983Notes

Reaction equation

[CH3:1][N:2]1[C:6](OS(C(F)(F)C(F)(F)C(F)(F)C(F)(F)F)(=O)=O)=[CH:5][C:4]([Br:24])=[N:3]1.[Br-].[CH3:26][C:27]1[CH:28]=[CH:29][C:30]([Zn+])=[N:31][CH:32]=1.O1CCCC1>CN(C)C=O.O.[Pd].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>[CH3:1][N:2]1[C:6]([C:30]2[CH:29]=[CH:28][C:27]([CH3:26])=[CH:32][N:31]=2)=[CH:5][C:4]([Br:24])=[N:3]1

Participants

Conditions

Temperature: 60 °C

Procedure

A solution of 1-methyl-3-bromo-5-(nonafluorobutanesulfonyloxy)pyrazole from Step 2 (0.36 g, 0.784 mmol) and tetrakis(triphenylphosphine) palladium (0) (0.09 g, 10 mol %) in dry N,N-dimethylformamide (2 mL) was stirred under nitrogen at 60° C. for 10 min, followed by addition of a solution of 5-methylpyridin-2-ylzinc bromide in tetrahydrofuran (0.5M, 1.8 mL, 0.9 mmol). The solution was stirred at 60° C. for 18 hours then cooled, diluted with water (30 ml), and extracted with ethyl acetate (2×20 mL). The extracts were dried (Na2SO4) and concentrated. Flash column chromatography on silica, eluting with 10% ethyl acetate-isohexane, gave 1-methyl-3-bromo-5-(5-methylpyridin-2-yl)pyrazole (0.081 g, 41%) as a yellow solid. MS (ES+) 252, 254 ([MH]+).

Workup

temperaturethen cooled
extractionextracted with ethyl acetate (2×20 mL)
dry with materialThe extracts were dried (Na2SO4)
concentrationconcentrated
washFlash column chromatography on silica, eluting with 10% ethyl acetate-isohexane

Sources & evidence

ORD record: ord-ebaaa54eef7542cfbb6e900297dd69be
Source dataset: uspto-grants-2006_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07041689B2

Reaction notes

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