7-Methoxy-5,11-dioxa-benzo[b]fluoren-10-one → 7-Hydroxy-5,11-dioxa-benzo[b]fluoren-10-one

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Reaction Steps

The starting methyl ether 18 (0.55 g, 2.1 mmol) was heated at 200° C. with Pyr-HCl (5 g) for one hour. The reaction mixture was allowed to cool to rt and worked up by partitioning between 2N HCl and EtOAc/MeOH. The organic layer was washed with NaHCO3 aq and brine and dried over MgSO4. Concentration gave 24 (0.29 g) as a tan solid: MP>300° C.; 1H NMR (DMSO-d6) δ 11.2 (br s, 1H), 8.14-8.07 (m, 2H), 7.87 (d, 1H, J=8.5 Hz), 7.76-7.70 (m, 1H), 7.55-7.52 (m, 1H), 7.09 (d, 1H, J=1.9 Hz), 7.02 (dd, 1H, J=8.8 Hz, 1.9 Hz); MS APCI 253 (M+H)+.

Provenance & Evidence