1,2-Dibromoethane → 7-Bromo-2-ethyl-4-methoxypyrazolo[1,5-a]pyridine

HRID 9189Notes

Reaction equation

C([Li])CCC.[CH2:6]([C:8]1[CH:18]=[C:11]2[C:12]([O:16][CH3:17])=[CH:13][CH:14]=[CH:15][N:10]2[N:9]=1)[CH3:7].[Br:19]CCBr.[Cl-].[NH4+]>O1CCCC1>[Br:19][C:15]1[N:10]2[N:9]=[C:8]([CH2:6][CH3:7])[CH:18]=[C:11]2[C:12]([O:16][CH3:17])=[CH:13][CH:14]=1

Participants

Conditions

Temperature: -78 °C

Procedure

n-Butyllithium (1.31 mL) was slowly added dropwise to a solution of 2-ethyl-4-methoxypyrazolo[1,5-a]pyridine (303 mg) in tetrahydrofuran (15 mL) at −78° C. After stirring the mixture at −78° C. for 1 hour, 1,2-dibromoethane (0.18 mL) was added and stirring was continued for 1 hour. Saturated aqueous ammonium chloride was added, extraction was performed with ethyl acetate, the extract was washed with brine and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography (20 g), and the title compound (282 mg) was obtained from the n-hexane:ethyl acetate (5:1) fraction as a colorless oil.

Workup

stirringstirring
waitwas continued for 1 hour
extractionextraction
washthe extract was washed with brine
dry with materialdried over magnesium sulfate
distillationthe solvent was distilled off under reduced pressure

Sources & evidence

ORD record: ord-b182e6e6acd04d0da1ff082f2af748a0
Source dataset: uspto-grants-2006_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07091215B2

Reaction notes

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