Lithium Hydroxide → 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylic acid

HRID 626608Notes

Reaction equation

HRID 626608 reaction equation
[CH3:1][C:2]1[N:3]=[C:4]2[CH:9]=[C:8]([CH3:10])[CH:7]=[CH:6][N:5]2[C:11]=1[C:12]([O:14]CC)=[O:13].[Li+].[OH-]>C(O)C>[CH3:1][C:2]1[N:3]=[C:4]2[CH:9]=[C:8]([CH3:10])[CH:7]=[CH:6][N:5]2[C:11]=1[C:12]([OH:14])=[O:13]

Participants

4

Reactant 2

HCID 3939Lithium HydroxideHCID 682232ethyl 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylate

Product 1

HCID 27362542,7-dimethylimidazo[1,2-a]pyridine-3-carboxylic acidYield 82.5%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

The ethyl 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylate (6.4 g, 29.3 mmol) was dissolved in 75 mL of ethanol (95%), 1 M LiOH (60 mL, 60 mmol) was added and reaction was heated to reflux for 36 hours. The resulting solution was concentrated to dryness and then made acidic (pH˜2-3) with the addition of 4 N HCl; resulting solids were collected by filtration and rigorously dried to give 4.6 grams (82%) of 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylic acid, an off-white solid. mp 180-183° C.; 1H NMR (300 MHz, CD3OD) δ 9.52 (d, J=7.1 Hz, 1H), 7.73 (td, J=1.8, 0.9, 0.9 Hz, 1H), 7.48 (dd, J=7.1, 1.3 Hz, 1H), 2.81 (s, 3H), 2.63 (s, 3H). HRMS (EI), M+1 calcd. for C10H11N2O2, 191.0815; found 191.0837. Retention time=0.6-0.7 minutes (mobile phase: 60% water:acetonitrile).

Workup

  1. customreaction
  2. temperaturewas heated
  3. temperatureto reflux for 36 hours
  4. concentrationThe resulting solution was concentrated to dryness
  5. additionwith the addition of 4 N HCl
  6. customresulting solids
  7. filtrationwere collected by filtration
  8. customrigorously dried

Sources & evidence

ORD record
ord-6f5d659340854f6181da6eddb6aa57cd
Source dataset
uspto-grants-2016_04
Patent number
US09309238B2

Reaction notes

Loading…