p-Toluenesulfonic acid → 2,2-Dimethyl-5-[4-(2-methyl-benzylsulfanyl)-benzylidene]-[1,3]dioxane-4,6-dione

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Reaction Steps

Pyrrolidine (0.45 mL, 5.27 mmol) was added to a solution of aldehyde 28.1 in diethyl ether (20 mL) and the mixture was sonicated for 5 minutes. The mixture was then added to a solution of Meldrum's acid (0.73 g, 5.08 mmol) in diethyl ether (20 mL) and the resultant mixture was sonciated for 5 minutes, forming a solid. The solid was filtered, rinsed with diethyl ether, and then suspended in DCM (10 mL). p-Toluenesulfonic acid (0.97 g, 5.10 mmol) was then added to the suspension and the suspension was sonicated until clear. The solvent was removed under reduced pressure, and the resulting residue was taken up in diethyl ether and partitioned between water and ethyl acetate. The aqueous layer was extracted 2 additional times with ethyl acetate. The combined organic layers were washed with water, dried (Na2SO4), and concentrated in vacuo to yield 1.05 g (54%) of 2,2-Dimethyl-5-[4-(2-methyl-benzylsulfanyl)-benzylidene]-[1,3]dioxane-4,6-dione (28.2) as a yellow oil The resulting yellow oil was used without further purification. LC/MSD m/e: 391.1 (M+Na).

Provenance & Evidence