Methyl iodide → 5-(tert-butyl-dimethyl-silanyloxymethyl)-1,4-dimethyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole

HRID 915423Notes

Reaction equation

[C:1]([Li])(C)(C)C.CCCCC.Br[C:12]1[C:13]([C:27]2[CH:32]=[CH:31][C:30]([C:33]([F:36])([F:35])[F:34])=[CH:29][CH:28]=2)=[N:14][N:15]([CH3:26])[C:16]=1[C:17]([CH3:25])([CH3:24])[O:18][SiH2:19][C:20]([CH3:23])([CH3:22])[CH3:21].CI>C1COCC1>[C:20]([SiH2:19][O:18][C:17]([CH3:25])([CH3:24])[C:16]1[N:15]([CH3:26])[N:14]=[C:13]([C:27]2[CH:32]=[CH:31][C:30]([C:33]([F:36])([F:35])[F:34])=[CH:29][CH:28]=2)[C:12]=1[CH3:1])([CH3:23])([CH3:22])[CH3:21]

Participants

Conditions

Temperature: -78 °C

Procedure

A 1.5 M solution of tert-butyllithium in pentane (0.5 ml, 748 μmol) was added dropwise to a solution of 4-bromo-5-(tert-butyl-dimethyl-silanyloxymethyl)-1-methyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole (280 mg, 623 μmol; example 8 b]) in THF (2 ml) at −78° C. under an argon atmosphere. After 15 min methyl iodide (177 mg, 1.2 mmol) was added at −78° C. The reaction mixture was stirred for another 30 min at −78° C. and then for 2 h at RT. After quenching with saturated aqueous NaHCO3 solution the reaction mixture was partitioned between tert-butyl methyl ether and water. The ether phase was dried over sodium sulfate and concentrated in vacuo to give 240 mg (620 μmol, quant.) 5-(tert-butyl-dimethyl-silanyloxymethyl)-1,4-dimethyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole as yellow oil which was used in the next step without further purification.

Workup

customat −78° C.
waitfor 2 h at RT
customAfter quenching with saturated aqueous NaHCO3 solution the reaction mixture
customwas partitioned between tert-butyl methyl ether and water
dry with materialThe ether phase was dried over sodium sulfate
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-c97bf5ab22a14925b6b131251cffd7a2
Source dataset: uspto-grants-2007_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07265149B2

Reaction notes

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