Lithium hydroxide, monohydrate → 5-Nitroindole-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

LiOH.H2O (1.06 g, 46.2 mmol, 2.1 eq.) was added to a suspension of 5-nitro-1H-indole-2-carboxylic acid ethyl ester (II) (5.15 g, 22 mmol, 1 eq.) in THF/MeOH/H2O 1:1:2 (180 ml). The final suspension turned to dark yellow and was stirred at 25° C. After 30 min the solubilization was complete and total conversion was achieved after 6 hours. The reaction mixture was cooled to 0° C. and quenched with HCl 2N until the solution reached pH 5. Organic volatiles were removed under reduced pressure and the white precipitate was filtered and dried to give the compound of formula (III). Yield=4.53 g (quantitative). Same procedure on 50 g scale afforded 42.2 g of the compound of formula (III) (96% yield).

Provenance & Evidence