Acetic Acid → 6-bromo-2,2-dimethyl-3-methylene-2,3-dihydro-4H-chromen-4-one

HRID 594881

Reaction equation

CN(C)CN(C)C.[Br:8][C:9]1[CH:10]=[C:11]2[C:16](=[CH:17][CH:18]=1)[O:15][C:14]([CH3:20])([CH3:19])[CH2:13][C:12]2=[O:21].[C:22](O)(=O)C.C(OC(=O)C)(=O)C>O1CCCC1>[Br:8][C:9]1[CH:10]=[C:11]2[C:16](=[CH:17][CH:18]=1)[O:15][C:14]([CH3:19])([CH3:20])[C:13](=[CH2:22])[C:12]2=[O:21]

Participants

Conditions

Temperature: 70 °C

Procedure

N,N,N′,N′-tetramethylmethanediamine (4.8 g, 47 mmol) was added to a solution of 6-bromo-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one (3.0 g, 12 mmol) and acetic acid (0.67 ml, 12 mmol) in tetrahydrofuran (43 ml), and the mixture was stirred at 70° C. for 24 hours. To the mixture was added acetic anhydride (4.4 ml, 47 mmol), and the mixture was stirred at 70° C. for 4 hours and concentrated in vacuo. The residue was directly purified by silica gel column chromatography (hexane/ethyl acetate=20:1) to afford 6-bromo-2,2-dimethyl-3-methylene-2,3-dihydro-4H-chromen-4-one (2.8 g).

Workup

stirringthe mixture was stirred at 70° C. for 4 hours
concentrationconcentrated in vacuo
customThe residue was directly purified by silica gel column chromatography (hexane/ethyl acetate=20:1)

Sources & evidence

ORD record: ord-3d64f1bf0ce24835970266559e585534
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09242973B2

Linked notes

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