Yield:-

Reaction Conditions:

with lithium hydroxide;water in tetrahydrofuran at 100; for 24 h;

Steps:

To 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 R_t=0.47 min., column G

References:

US2005/124623,2005,A1 Location in patent:Page/Page column 44