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

HRID 1893386Notes

Reaction equation

O[Li].O.C([O:6][C:7]([C:9]1[NH:10][C:11]2[C:16]([CH:17]=1)=[CH:15][C:14]([N+:18]([O-:20])=[O:19])=[CH:13][CH:12]=2)=[O:8])C>C1COCC1.CO.O>[N+:18]([C:14]1[CH:15]=[C:16]2[C:11](=[CH:12][CH:13]=1)[NH:10][C:9]([C:7]([OH:8])=[O:6])=[CH:17]2)([O-:20])=[O:19]

Participants

Conditions

Temperature: 25 °C

Procedure

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).

Workup

waittotal conversion was achieved after 6 hours
temperatureThe reaction mixture was cooled to 0° C.
customquenched with HCl 2N until the solution
customOrganic volatiles were removed under reduced pressure
filtrationthe white precipitate was filtered
customdried

Sources & evidence

ORD record: ord-76e6937126254034aed1676936b65355
Source dataset: uspto-grants-2013_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08513241B2

Reaction notes

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