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

HRID 1181866Notes

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-00f69cf14788421e96a6c13393a930a5
Source dataset: uspto-grants-2007_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07285666B2

Reaction notes

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