Hydrochloric Acid → Isochromane

Participants

Reaction Steps

2-phenylethanol (48.8 g,) and paraformaldehyde (15 g,) were mixed and stirred on an ice bath while a stream of hydrogen chloride gas was passed vigorously through the suspension for 2 hr. The ice-bath was removed and the flow of hydrogen chloride was decreased. The mixture was stirred at room temperature for a further 4 hr. during which time the mixture cleared, after which the reaction mixture stood overnight at room temperature. Aqueous sodium hydroxide solution (100 g/100 ml) was added cautiously, with stirring to the reaction mixture over a period of 30 min. The mixture was heated at reflux for 2 hr., cooled and the oil extracted with ether (3×100 ml). The ether layer was dried (magnesium sulphate) and the solvent removed in vacuo. The residue was distilled under vacuum to give isochroman (45.7 g, b.pt 84.5°-85°/8 mmHg)

Provenance & Evidence