Sodium Hydroxide → 2-(2-hydroxy-1-methylethyl)-1H-benzoimidazole-4-carboxylic acid

HRID 1098350Notes

Reaction equation

C[O:2][C:3](=[O:12])[C:4]1[CH:9]=[CH:8][CH:7]=[C:6]([NH2:10])[C:5]=1[NH2:11].C[O:14][C:15](=O)[CH:16]([CH3:19])[CH2:17]O.[OH-].[Na+]>Cl>[OH:14][CH2:15][CH:16]([C:19]1[NH:10][C:6]2[CH:7]=[CH:8][CH:9]=[C:4]([C:3]([OH:2])=[O:12])[C:5]=2[N:11]=1)[CH3:17]

Participants

Conditions

Temperature: 90 °C

Procedure

To a solution of 2,3-diaminobenzoic acid methyl ester (2.1 g, 14.1 mmol) in 4 M HCl (90 mL) was added 2-methyl-3-hydroxypropionic acid methyl ester (5 g, 42.3 mmol). The mixture was stirred at ˜90° C. for 24 h. It was neutralized by use of aqueous sodium hydroxide solution to pH ˜3, and concentrated to dryness. The residue was suspended in methanol, and filtered through a filter paper. After the filtrate was concentrated, the remaining solid residue was dissolved in water and washed with ethyl acetate. The aqueous solution was evaporated in vacuo yielding the title intermediate as a pale yellow oil (˜800 mg). The crude product was used in the next step without further purification. (m/z): [M+H]+ calcd for C11H12N2O3 221.09; found 221.3. 1H-NMR (CD3OD) δ (ppm) 8.1 (d, 1H), 7.9 (m, 1H), 7.6 (t, 1H), 3.8 (m, 2H), 3.6 (m, 1H), 1.4 (d, 3H).

Workup

concentrationconcentrated to dryness
filtrationfiltered through a filter paper
concentrationAfter the filtrate was concentrated
dissolutionthe remaining solid residue was dissolved in water
washwashed with ethyl acetate
customThe aqueous solution was evaporated in vacuo

Sources & evidence

ORD record: ord-c1dca6bdaeb34c2e8ccf5567fdce1d26
Source dataset: uspto-grants-2012_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08143279B2

Reaction notes

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