Isopropyl iodide → Ethyl 5-iodo-1-isopropyl-1H-pyrazole-4-carboxylate

HRID 711026Notes

Reaction equation

[I:1][C:2]1[C:6]([C:7]([O:9][CH2:10][CH3:11])=[O:8])=[CH:5][NH:4][N:3]=1.C(=O)([O-])[O-].[Cs+].[Cs+].I[CH:19]([CH3:21])[CH3:20]>CN(C)C=O.O>[I:1][C:2]1[N:3]([CH:19]([CH3:21])[CH3:20])[N:4]=[CH:5][C:6]=1[C:7]([O:9][CH2:10][CH3:11])=[O:8]

Participants

Conditions

Temperature: 60 °C

Procedure

To a solution of ethyl 3-iodopyrazole-4-carboxylate (1.58 g, 5.94 mmol, Truong; et al. Bioorg. Med. Chem. Lett., 19, 4920 (2009)) in 20 mL N,N-dimethylformamide was added cesium carbonate (3.87 g, 11.9 mmol) and 2-iodopropane (0.89 mL, 8.90 mmol). The mixture was stirred 2 hours at 60° C. and then cooled to ambient temperature. The reaction mixture was diluted with 150 mL water and extracted with 2×100 mL diethyl ether. The combined organics were washed with 50 mL brine, dried over sodium sulfate, filtered and concentrated. The resultant oil was purified by flash chromatography (7-60% ethyl acetate/heptane gradient, 50 g silica) to yield 340 mg of ethyl 5-iodo-1-isopropyl-1H-pyrazole-4-carboxylate as a clear oil which crystallized on standing and 740 mg of ethyl 3-iodo-1-isopropyl-1H-pyrazole-4-carboxylate as a clear oil.

Workup

temperaturecooled to ambient temperature
extractionextracted with 2×100 mL diethyl ether
washThe combined organics were washed with 50 mL brine
dry with materialdried over sodium sulfate
filtrationfiltered
concentrationconcentrated
customThe resultant oil was purified by flash chromatography (7-60% ethyl acetate/heptane gradient, 50 g silica)

Sources & evidence

ORD record: ord-b903b0c08f744b65b3343806cf4a9fe6
Source dataset: uspto-grants-2015_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09181252B2

Reaction notes

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