7,9-Dimethoxy-5-oxa-11-thia-benzo[b]fluoren-10-one → 7,9-Dihydroxy-5-oxa-11-thia-benzo[b]fluoren-10-one

Participants

Reaction Steps

Example 29 (0.26 g, 0.83 mmol) and Pyr-HCl (5 g) were heated together at 210° C. for 30 minutes. The reaction was worked up by partitioning between EtOAc/MeOH and 2N HCl aq. The organic layer was washed with brine and dried over MgSO4. The organic layer was concentrated and the product triturated with MeOH to yield the desired pdt 31 as a tan solid (0.17 g): Mp>300° C.; 1H NMR (DMSO-d6) δ 12.49 (s, 1H), 11.09 (s, 1H), 8.22 (d, 1H, J=3.4 Hz), 8.20 (d, 1H, J=4.0 Hz), 7.76-7.61 (m, 2H), 6.61 (d, 1H, J=2.1 Hz), 6.31 (d, 1H, J=2.1 Hz); MS 283 (M−H)−.

Provenance & Evidence