Trifluoroacetic acid → 2-ethyl-5-(4-fluoro-benzylamino)-2H-pyrazole-3-carboxylic acid methyl ester

HRID 1952097Notes

Reaction equation

[CH3:1][O:2][C:3]([C:5]1[N:6]([CH2:11][CH3:12])[N:7]=[C:8]([NH2:10])[CH:9]=1)=[O:4].[F:13][C:14]1[CH:21]=[CH:20][C:17]([CH:18]=O)=[CH:16][CH:15]=1.C([SiH](CC)CC)C.FC(F)(F)C(O)=O>C(#N)C>[CH3:1][O:2][C:3]([C:5]1[N:6]([CH2:11][CH3:12])[N:7]=[C:8]([NH:10][CH2:18][C:17]2[CH:20]=[CH:21][C:14]([F:13])=[CH:15][CH:16]=2)[CH:9]=1)=[O:4]

Participants

Conditions

Temperature: 80 °C

Procedure

To 5-amino-2-ethyl-2H-pyrazole-3-carboxylic acid methyl ester (527, 1.00 g, 5.91 mmol) in acetonitrile (27.5 mL) were added 4-fluorobenzaldehyde (528, 0.660 mL, 6.26 mmol), triethylsilane (4.77 mL, 0.0298 mol) and trifluoroacetic acid (2.38 mL, 0.0310 mol). The reaction was stirred at 80° C. for 4 hours, then concentrated, poured into aqueous potassium carbonate, and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated and purified by silica gel column chromatography eluting with 20% to 100% ethyl acetate in hexane to give a white solid (529, 1.00 g, 61%).

Workup

concentrationconcentrated
additionpoured into aqueous potassium carbonate
extractionextracted with ethyl acetate
dry with materialThe organic layer was dried over anhydrous sodium sulfate
filtrationfiltered
concentrationThe filtrate was concentrated
custompurified by silica gel column chromatography
washeluting with 20% to 100% ethyl acetate in hexane
customto give a white solid (529, 1.00 g, 61%)

Sources & evidence

ORD record: ord-300bcd566294422a87f2a8c20fcbd094
Source dataset: uspto-grants-2013_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08404700B2

Reaction notes

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