5'-Bromo-2'-hydroxyacetophenone → 6-bromo-2-(tetrahydro-2H-pyran-3-yl)chroman-4-one

Participants

Reaction Steps

A mixture of 1-(5-bromo-2-hydroxy-phenyl)-ethanone (19.45 g, 90.9 mmol), tetrahydro-2H-pyran-3-carbaldehyde (10 g, 90.9 mmol) and borax (34.6 g, 90.9 mmol) in ethanol (120 mL) and H2O (200 mL) was refluxed for one day. The reaction mixture was cooled, diluted with an equal volume of H2O and extracted with ethyl acetate. The organic layer was dried over anhydrous Na2SO4, filtered, and evaporated to give 6-bromo-2-(tetrahydro-2H-pyran-3-yl)chroman-4-one (4 g, 15%). 1H-NMR (CDCl3): 1.30 (m, 2H), 1.48 (m, 5H), 1.64 (m, 4H), 1.94 (d, 2H), 6.86 (d, 1H), 7.51 (dd, 1H), 7.92 (d, 1H).

Provenance & Evidence