[O:1]1CCO[C:2]21[CH2:21][C:10]1[CH:11]=[C:12]3[C:16](=[CH:17][C:9]=1[CH2:8][CH2:7][CH2:6]2)[N:15]([C:18](=[O:20])[CH3:19])[N:14]=[CH:13]3.[Li+].[OH-]>FC1C=CC(N2C3C(=CC=C(CCCC(O)=O)C=3)C=N2)=CC=1.C1COCC1.O>[C:18]([N:15]1[C:16]2[C:12](=[CH:11][C:10]3[CH2:21][C:2](=[O:1])[CH2:6][CH2:7][CH2:8][C:9]=3[CH:17]=2)[CH:13]=[N:14]1)(=[O:20])[CH3:19]In a 10 L 3 necked flask, 1-(5,7,8,9-tetrahydro-1H-spiro[cyclohepta[f]indazole-6,2′-[1,3]dioxolan]-1-yl)ethanone (79) (440 g, 1.54 mol) was dissolved in THF (5.2 L). A solution of LiOH (143 g, 5.97 mol) in water (3.5 L) was added. The mixture was stirred at rt for about 50 min. The mixture was extracted with EtOAc (2×15 L). The combined organic layers were washed with water, dried over MgSO4, filtered and concentrated under reduced pressure. The residue was recrystallized from ethanol to give 1-acetyl-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one (81) (220 g, 59% yield) as a light yellow solid. 1H NMR (300 MHz, CDCl3): δ 10.05 (s, 1H), 7.96 (s, 1H), 7.47 (s, 1H), 7.20 (s, 1H), 4.03 (m, 4H), 3.16 (s, 2H), 2.91 (m, 2H), 2.04 (m, 2H), 1.88 (m, 2H).
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