Benzaldehyde → (3E)-6-Fluoro-2,3-dihydro-3-(phenylmethylene)-4H-1-benzopyran-4-one

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Reaction Steps

6-Fluoro-4-chromanone (5.0 g, 30.1 mmol) and 3.35 g (31.6 mmol) benzaldehyde were dissolved in 100 mL of EtOH, and HCl gas was bubbled through the solution until it was nearly boiling. The flask was then capped, allowed to cool to room temperature and stirred overnight. The solids were filtered off and rinsed with a minimum amount of Et2O to provide 1-1 as a light-pinkish solid. Data for 1-1: 1HNMR (500 MHz, CDCl3) δ 7.9 (s, 1H), 7.65 (m, 1H), 7.5-7.4 (m, 3H), 7.3 (m, 2H), 7.2 (m, 1H), 6.95 (m, 1H), 5.35 (s, 2H) ppm. LC-MS: rt=2.8 min, m/z=255 (M+1).

Provenance & Evidence