Sodium borohydride → Ethyl 2-(3,5-dibromothiophen-2-yl)-2-hydroxyacetate

HRID 590985Notes

Reaction equation

[BH4-].[Na+].[Br:3][C:4]1[CH:8]=[C:7]([Br:9])[S:6][C:5]=1[C:10](=[O:16])[C:11]([O:13][CH2:14][CH3:15])=[O:12]>O1CCCC1.Cl>[Br:3][C:4]1[CH:8]=[C:7]([Br:9])[S:6][C:5]=1[CH:10]([OH:16])[C:11]([O:13][CH2:14][CH3:15])=[O:12]

Participants

Conditions

Temperature: -10 °C

Procedure

Under a nitrogen atmosphere, sodium borohydride (0.14 g, 3.7 mmol) was added portionwise to a solution of ethyl 2-(3,5-dibromothiophen-2-yl)-2-oxoacetate (10a) (0.42 g, 1.24 mmol) in anhydrous tetrahydrofuran (10 mL), previously cooled to −10° C. After 30 minutes stirring, a few drops of 1 M hydrochloric acid were added and the resulting precipitate was filtered. The filtrate was concentrated in vavuo. The residue was dissolved in brine, and extracted with ethyl acetate (2×20 mL). The organic layer was dried over sodium sulfate, filtered, and evaporated to dryness. The residue was purified by flash chromatography on silica gel (cyclohexane/ethyl acetate 80/20) to provide the desired alcohol (10b) (0.32 g, 0.93 mmol, 75%).

Workup

filtrationthe resulting precipitate was filtered
concentrationThe filtrate was concentrated in vavuo
dissolutionThe residue was dissolved in brine
extractionextracted with ethyl acetate (2×20 mL)
dry with materialThe organic layer was dried over sodium sulfate
filtrationfiltered
customevaporated to dryness
customThe residue was purified by flash chromatography on silica gel (cyclohexane/ethyl acetate 80/20)

Sources & evidence

ORD record: ord-cca818d6b29c452482a7916ebcd2503b
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09238026B2

Reaction notes

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