Dimethyl 3-oxoglutarate → Methyl 2-(2-methoxy-2-oxoethyl)thiophene-3-carboxylate

Reaction equation

[CH3:1][O:2][C:3]([CH2:5][C:6]([CH2:8][C:9]([O:11][CH3:12])=[O:10])=O)=[O:4].O[CH:14]1[CH2:19]SC(O)C[S:15]1.[Br-].[Li+]>O1CCOCC1>[CH3:1][O:2][C:3]([CH2:5][C:6]1[S:15][CH:14]=[CH:19][C:8]=1[C:9]([O:11][CH3:12])=[O:10])=[O:4]

Participants

Procedure

100.0 g of dimethyl 1,3-acetonedicarboxylate was dissolved in 2,800 ml of dioxane, and added thereto were 52.5 g of 2,5-dihydroxy-1,4-dithiane and 5.0 g of lithium bromide. The resulting mixture was refluxed for 15 hours, cooled to room temperature, and concentrated by evaporation. To the residue, 1,000 ml of n-hexane was added, stirred, and the hexane layer was separated. This extraction procedure was repeated twice using 500 ml portions of n-hexane. The separated n-hexane layers were combined and concentrated under reduced pressure to obtain 60.9 g (yield of 49%) of the title compound as an oil, which was directly used in the next step without any purification. An analytical sample of the title compound could be obtained by vacuum distillation.