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

HRID 405827Notes

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-9abc6be3474d4b1b9ddc20523181462e
Source dataset: uspto-grants-2014_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08754071B2

Reaction notes

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