C([O:3][C:4]([C:6]1[C:10]2[N:11]=[CH:12][N:13]=[C:14]([Cl:15])[C:9]=2[NH:8][CH:7]=1)=[O:5])C.O[Li].O>C1COCC1.O>[Cl:15][C:14]1[C:9]2[NH:8][CH:7]=[C:6]([C:4]([OH:5])=[O:3])[C:10]=2[N:11]=[CH:12][N:13]=1To a solution of 7-chloro-4,6-diazaindole 5 (4.0 g, 18 mmol) in THF (90 mL) was added a solution of LiOH.H2O (2.5 g, 59 mmol) in H2O (60 mL). The reaction mixture was stirred at 100° C. for 1 d, concentrated and recrystallized from H2O (20 mL). The crystals were collected by filtration, washed with H2O and dried under high vacuum. The off-white solid was shown to be the lithium salt of the diazaindole carboxylic acid 6 (quantitative), which was used without further purification. 1H NMR: (500 MHz, DMSO-d6) δ 8.28 (s, 1H), 8.14 (s, 1H); LC/MS: (ES+) m/z (M+H)+=198; HPLC Rt=0.47 min., column G.
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