[Na].[C:2]1([N:8]2[C:16]3[CH2:15][CH2:14][CH2:13][C:12](=[O:17])[C:11]=3[CH:10]=[N:9]2)[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH:18](OCC)=[O:19].C(O)C>C1(C)C=CC=CC=1.O>[O:17]=[C:12]1[CH:13]([CH:18]=[O:19])[CH2:14][CH2:15][C:16]2[N:8]([C:2]3[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=3)[N:9]=[CH:10][C:11]1=2To a stirred suspension of sodium (0.75 g, 33 mmol) in toluene (200 mL) was added 1-phenyl-6,7-dihydro-1H-indazol-4(5H)-one (2.6 g, 123 mmol). The reaction mixture was stirred for 30 minutes and a solution of ethyl formate (2.22 mL, 276 mmol) in toluene (10 mL) was added over 10 minutes followed by absolute ethanol (1 mL). The reaction was stirred at room temperature for 40 hours. The reaction mixture was cautiously poured into ice-cooled water (100 mL). The organic layer was separated. The aqueous layer was extracted with diethylether (100 mL) and acidified with 6N HCl to a pH between 5 and 6. The aqueous layer was then extracted with dichloromethane (3×75 mL). The combined organic layer was dried using sodium sulfate and concentrated under reduced pressure to give a residue which on trituration with hexane gave the desired product (1.1 g, 32%) as a solid. 1H NMR (CDCl3, 400 MHz): δ 10.75 (s, 1H), 8.00 (s, 1H), 7.61-7.54 (m, 5H), 7.48-7.45 (m, 1H), 3.00-2.96 (m, 2H), 2.76-2.70 (m, 2H); LCMS [M+H]: 241.
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