Lithium Chloride → 1,2,3,4Tetrahydro-8-methoxy-3-(2-propenyl)2-oxo-naphthalene

HRID 1078067Notes

Reaction equation

COC([CH:5]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][C:13]=2[O:15][CH3:16])[CH2:8][CH:7]([CH2:17][CH:18]=[CH2:19])[C:6]1=[O:20])=O.[Cl-].[Li+]>CS(C)=O.O>[CH3:16][O:15][C:13]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:14]=1[CH2:5][C:6](=[O:20])[CH:7]([CH2:17][CH:18]=[CH2:19])[CH2:8]2

Participants

Conditions

Temperature: 125 °C

Procedure

To a solution of 10.3 g (37.6 mmol) of 1,2,3,4-tetrahydro-8-methoxy-2-oxo-3-(2-propenyl)-1-naphthalene carboxylic acid methyl ester in 26.3 mL of DMSO and 1.1 mL of water was added 1.9 g (45.1 mmol) of lithium chloride. The reaction mixture was heated at 125° C. (bath temperature) for five hours. TLC analysis showed no starting material remaining. The mixture was cooled to room temperature and extracted with ethyl acetate (1 L). The organic layer was washed with 10% aqueous calcium sulfate (an efficient way of removing DMSO from organic layer), dried (MgSO4), filtered and concentrated in vacuo. The crude product was purified by liquid chromatography on 800 g silica gel 60 (230-400 m), eluting with hexane-ethyl acetate (3:1), and collecting 40 mL fractions. Fractions 26-53 gave 7.65 g (94%) of pure title compound as a yellow oil.

Workup

temperatureThe mixture was cooled to room temperature
extractionextracted with ethyl acetate (1 L)
washThe organic layer was washed with 10% aqueous calcium sulfate (an efficient way of removing DMSO from organic layer),
dry with materialdried (MgSO4)
filtrationfiltered
concentrationconcentrated in vacuo
customThe crude product was purified by liquid chromatography on 800 g silica gel 60 (230-400 m)
washeluting with hexane-ethyl acetate (3:1)
customcollecting 40 mL fractions

Sources & evidence

ORD record: ord-85980d931ab5465a8b989128b775d592
Source dataset: uspto-grants-1996_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05545755

Reaction notes

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