Sodium Sulfate → methyl 2-[4-(3,4-dihydro-2H-1-benzopyran-6-yl)-2,5-dimethylthiophen-3-yl]prop-2-enoate

Participants

Reaction Steps

A mixture of methyl 2-[4-(3,4-dihydro-2H-1-benzopyran-6-yl)-2,5-dimethylthiophen-3-yl]-2-hydroxypropanoate (42b) (130 mg, 0.38 mmol), p-toluenesulfonic acid monohydrate (357 mg, 1.88 mmol) and a spoon of sodium sulfate, in anhydrous toluene (3 mL), was refluxed for 16 hours. After cooling to room temperature, the reaction mixture was filtered and the filtrate was successively washed with a saturated solution of sodium bicarbonate (2×5 mL) and brine (5 mL). The organic layer was dried over sodium sulfate and concentrated in vacuo to provide the desired product (42c) (114 mg, 0.35 mmol, 93%) which was used without further purification.

Provenance & Evidence