Ethanol → 5-Methoxy-4-nitroindole-2-carboxylic acid

HRID 454310Notes

Reaction equation

[OH:1][C:2]1[C:3]([N+:16]([O-:18])=[O:17])=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6]([C:11]([O:13]CC)=[O:12])=[CH:5]2.[OH-].[K+].[CH2:21](O)C>O>[CH3:21][O:1][C:2]1[C:3]([N+:16]([O-:18])=[O:17])=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6]([C:11]([OH:13])=[O:12])=[CH:5]2

Participants

Conditions

Temperature: 50 °C

Procedure

Ethyl 5-hydroxy-4-nitroindole-2-carboxylate (1.0 g, 3.8 mmol) was suspended in a mixture of ethanol (20 ml) and water (5 ml). Potassium hydroxide (840 mg) was added and the mixture stirred at 50° C. under an atmosphere of nitrogen for 1 hour then cooled to ambient temperature. The solvent was evaporated in vacuo and the residue re-dissolved in water (25 ml). The pH was adjusted to pH2 using aqueous hydrochloric acid (2M). The resulting precipitate was filtered off, washed with water and dried in vacuo to give 5-methoxy-4-nitroindole-2-carboxylic acid (790 mg). This was used without further purification.

Workup

temperaturethen cooled to ambient temperature
customThe solvent was evaporated in vacuo
dissolutionthe residue re-dissolved in water (25 ml)
filtrationThe resulting precipitate was filtered off
washwashed with water
customdried in vacuo

Sources & evidence

ORD record: ord-b216ae4251fd4270ad7c4839a7170357
Source dataset: uspto-grants-2013_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08492560B2

Reaction notes

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