Hydrochloric Acid → 4-[1-(3-Methylthiophen-2-yl)-meth-(e)-ylidene]-2-(2,4,6-trimethylphenyl)cyclopentane-1,3-dione

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Reaction Conditions

Reaction Steps

Potassium tertiary butoxide (0.53 g, 4.72 mmol) is added to a cold solution of mixture of 3-Methoxy-2-(2,4,6-trimethylphenyl)cyclopent-2-enone (0.5 g, 2.16 mmol) in tetrahydrofuran (5 ml). The reaction mixture is stirred for 30 minutes at 0° C. and to this mixture is added a solution of 3-methyl-2-thiophene carboxaldehyde (0.23 g, 1.82 mmol) in tetrahydrofuran (1 ml). The reaction mixture is stirred at 0° C. for 2 hours, acidified to pH 1 with 2N aqueous hydrochloric acid and the aqueous phase is extracted with ethyl acetate (3×25 ml), the organic phases are combined, washed with water, and dried over anhydrous sodium sulphate. The mixture is filtered, and the filtrate is evaporated under reduced pressure to give a crude residue. The crude residue is dissolved in acetone (6 ml), added concentrated hydrochloric acid (3 ml) and the resulting solution is heated to 60° C. for 8 hrs. The reaction mixture is diluted with water and extracted with ethyl acetate (3×25 ml). The combined organics are washed with brine, dried over sodium sulphate, filtered and concentrated in vacuum to give a residue. This residue is then purified using silica gel column chromatography to give 4-[1-(3-methylthiophen-2-yl)-meth-(E)-ylidene]-2-(2,4,6-trimethylphenyl)cyclopentane-1,3-dione (100 mg).

Provenance & Evidence