[Br:1][C:2]1[CH:7]=[C:6]([O:8]C)[CH:5]=[CH:4][C:3]=1[C:10](=[O:22])[CH2:11][C:12]1[CH:17]=[C:16]([O:18]C)[CH:15]=[CH:14][C:13]=1OC.N1C(=O)CC[C@H]1C(O)=O.Cl>>[Br:1][C:2]1[CH:7]=[C:6]([OH:8])[CH:5]=[CH:4][C:3]=1[C:10]1[O:22][C:13]2[CH:14]=[CH:15][C:16]([OH:18])=[CH:17][C:12]=2[CH:11]=1Compound 101 (1.25 g, 3.4 mmol) was heated at 200° C. with a large excess of Pyr-HCl and followed by TLC for reaction completion (approx 30 min to 1 h). The reaction mixture was allowed to cool to rt and then partitioned between 2 N HCl aq and EtOAc. The organic layer was washed with saturated NaHCO3 aq, brine, and then dried over MgSO4. After filtering, the reaction mixture was concentrated and chromatographed on silica gel (1:1 EtOAc/hexanes) to yield 0.96 g of the desired pdt: Mp=195° C.; 1H NMR (DMSO-d6) δ 10.33 (br s, 1 H), 9.23 (br s, 1 H), 7.70 (d, 1 H, J=8.6 Hz); 7.37 (d, 1 H, J=8.8 Hz), 7.21 (s, 1 H), 7.16 (d, 1 H, J=2.4 Hz), 6.97 (d, 1 H, J=2.4 Hz), 6.92 (dd, 1 H, J=8.7 Hz, 2.4 Hz), 6.75 (dd, 1 H, J=8.8 Hz, 2.4 Hz); MS 303 (M−H)−.
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