p-Toluenesulfonic acid → 7-Methoxy-spiro[1,3-benzodioxole-2,1'-cyclopentane]

Participants

Reaction Steps

A mixture of 3-methoxycatechol (22.6 g), cyclopentanone (27.1 g), methyl orthoformate (34.2 g), p-toluenesulfonic acid.monohydrate (0.2 g), and benzene (300 ml) was heated under reflux for 24 hours. After being allowed to stand for cooling, a dilute solution of sodium hydroxide was added to the mixture followed by extraction with ether. The organic layer was washed with a saturated saline and dried over anhydrous potassium carbonate. The solvent was distilled off under reduced pressure to give Compound IIax-a (30 g, 90%) as a colorless oily substance.

Provenance & Evidence