Ethanol → p-Imidazo(1,2-a)pyridin-2-ylhydratropic acid

HRID 1284096Notes

Reaction equation

HRID 1284096 reaction equation
[N:1]1[C:2]([C:10]2[CH:15]=[CH:14][C:13]([CH:16]([CH3:22])[C:17]([O:19]CC)=[O:18])=[CH:12][CH:11]=2)=[CH:3][N:4]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=12.C(O)C.[OH-].[Na+]>O>[N:1]1[C:2]([C:10]2[CH:15]=[CH:14][C:13]([CH:16]([CH3:22])[C:17]([OH:19])=[O:18])=[CH:12][CH:11]=2)=[CH:3][N:4]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=12

Participants

5

Reactant 3

HCID 702EthanolHCID 14798Sodium HydroxideHCID 12399251HCID 12399251, compound

Product 1

HCID 68752p-Imidazo(1,2-a)pyridin-2-ylhydratropic acidYield 55.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 8 g of ethyl 2-[4-(imidazo[1,2-a]pyridin-2-yl)phenyl]-propionate, 50 ml of ethanol, 1.4 g of sodium hydroxide and 10 ml of water is heated under reflux for 2 hours. The ethanol is distilled off under reduced pressure, and the residue is dissolved in water. The solution is adjusted to pH 6 by addition of dilute hydrochloric acid. The crystalline precipitate is filtered off, washed with water, and recrystallized from methanol to give 4 g of 2-[4-(imidazo[1,2-a]pyridin-2-yl)phenyl]propionic acid as colorless crystals melting at 244°-246°C with decomposition. The corresponding hydrochloride melts at 210°-211°C.

Workup

  1. temperatureis heated
  2. temperatureunder reflux for 2 hours
  3. distillationThe ethanol is distilled off under reduced pressure
  4. dissolutionthe residue is dissolved in water
  5. additionThe solution is adjusted to pH 6 by addition of dilute hydrochloric acid
  6. filtrationThe crystalline precipitate is filtered off
  7. washwashed with water
  8. customrecrystallized from methanol

Sources & evidence

ORD record
ord-fbd5b25eb7c64ca6bb9c9b49527d6ff7
Source dataset
uspto-grants-1976_08
Patent number
US03978071

Reaction notes

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