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

HRID 1045450Notes

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-28a646af0e604b2c9f49a3e48dc7f11b
Source dataset: uspto-grants-2013_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08569283B2

Reaction notes

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