Lithium Hydroxide → 1-Acetyl-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one

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Reaction Steps

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).

Provenance & Evidence