Hydrochloric Acid → 6-chloroisochroman

Participants

Reaction Steps

2-(3-Chlorophenyl)ethanol (48.2 g) and paraformaldehyde (10.8 g) were mixed and warmed to 70° on an oil bath. A stream of hydrogen chloride gas was passed vigorously through the suspension for about 7 hr. The reaction mixture was then allowed to stand at room temperature overnight. Aqueous sodium hydroxide solution (100 g/100 ml) was added cautiously to the reaction mixture. After the initial reaction subsided the rest of the alkali solution was run in fast and the resulting mixture was heated at reflux on an oil bath for 2 hr. The reaction mixture was cooled and extracted into ether (3×100 ml). The ether layer was dried (sodium sulphate) and evaporated in vacuo to give the 6-chloroisochroman as an oil (46 g), which was purified by distillation in vacuo (25.1 g, b.pt. 76°-80°/0.6 mmHg), characterised by its nmr spectrum.

Provenance & Evidence