Phosphorus pentachloride → 6-Chloro-8-methyl-3,4-dihydro-2H-1-benzopyran-4-one

Participants

Reaction Steps

Phosphorous pentachloride (0.95 g, 4.6 mmol) was added to a suspension of 3-(4-chloro-2-methylphenoxy)propionic acid (0.59 g; 2.7 mmol; from step (ii) above) in benzene (10 mL). The resultant clear solution was heated quickly to boiling and then cooled on an ice bath. Aluminium chloride (1.0 g; 7.5 mmol) was added in portions and, after complete addition, ice water was added. Extraction with ether, washing of the organic layer with NaHCO3/aq. and NaOH (2M; aq.), drying (Na2SO4) and concentration yielded 0.27 g (50%) of the sub-title compound.

Provenance & Evidence