Citric Acid → 6-Carbamoylimidazo[1,2-a]pyridine-3-carboxylic acid

HRID 1497892Notes

Reaction equation

[C:1]([C:3]1[CH:4]=[CH:5][C:6]2[N:7]([C:9]([C:12]([O:14]CC)=[O:13])=[CH:10][N:11]=2)[CH:8]=1)#[N:2].[Li+].[OH-].C(O)(=O)CC(CC(O)=O)(C(O)=O)[OH:22]>C1COCC1.CO>[C:1]([C:3]1[CH:4]=[CH:5][C:6]2[N:7]([C:9]([C:12]([OH:14])=[O:13])=[CH:10][N:11]=2)[CH:8]=1)(=[O:22])[NH2:2]

Participants

Conditions

Temperature: 60 °C

Procedure

To a stirring solution of ethyl 6-cyanoimidazo[1,2-a]pyridine-3-carboxylate (24q) (500 mg, 2.32 mmol) in THF:MeOH (4:1, 5 mL) was added 2N LiOH (4 mL). The reaction was heated at 60° C. for 2 h then acidified with 10% citric acid. The solvent was partially concentrated and the resulting solid was collected by vacuum filtration and was washed with excess water. The product was purified from the crude solid to afford 6-carbamoylimidazo[1,2-a]pyridine-3-carboxylic acid (110). 1H NMR (400 MHz, d6-DMSO) δ 9.80 (s, 1H), 8.33-8.31 (m, 1H), 8.29 (s, 1H), 7.95 (dd, J=2.0, 9.6 Hz, 1H), 7.83 (dd, J=0.8, 9.2 Hz, 1H), 7.69 (s, 1H). MS m/z 205.05 (M+1)+.

Workup

concentrationThe solvent was partially concentrated
filtrationthe resulting solid was collected by vacuum filtration
washwas washed with excess water
customThe product was purified from the crude solid

Sources & evidence

ORD record: ord-dcb1447f3986446287b165f181ed11a3
Source dataset: uspto-grants-2015_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09199981B2

Reaction notes

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