Bromobenzene → 2,2-Dimethyl-4-phenyl-2H-1-benzopyran-7-ol

Participants

Reaction Steps

Bromobenzene (141.3 g) in dry tethydrofuran (300 ml) was added to magnesium (23.7 g) in dry tetrahydrofuran (100 ml). 2,2-Dimethylchroman-4-one-7-ol (34.5 g) in dry tetrahydrofuran (250 ml) was then added and the solution refluxed for 48 hours. The mixture was poured into ammonium chloride solution, the tetrahydrofuran layer was separated and evaporated under reduced pressure. The aqueous layer was extracted with ethyl acetate and the organic layer and the residue from the tetrahydrofuran layer was shaken with 10% sodium hydroxide solution. The basic layer was acidified and re-extracted with ethyl acetate. The organic layers were dried (MgSO4). Removal of the solvent under reduced pressure gave an oil (26 g) which was chromatographed on silica. Elution with ether - petrol (1:1) gave the title compound (14 g).

Provenance & Evidence