Phosphorus oxychloride → 3-Formyl-2-methyl-8-nitro-imidazo[1,2-a]pyridine

HRID 1195738Notes

Reaction equation

HRID 1195738 reaction equation
O=P(Cl)(Cl)Cl.[CH3:6][C:7]1[N:8]=[C:9]2[C:14]([N+:15]([O-:17])=[O:16])=[CH:13][CH:12]=[CH:11][N:10]2[CH:18]=1.[C:19](=O)([O-])[OH:20].[Na+]>CN(C)C=O>[CH:19]([C:18]1[N:10]2[CH:11]=[CH:12][CH:13]=[C:14]([N+:15]([O-:17])=[O:16])[C:9]2=[N:8][C:7]=1[CH3:6])=[O:20]

Participants

5

Reactant 3

HCID 24813Phosphorus oxychloride2×HCID 516892Sodium BicarbonateHCID 218273482-Methyl-8-nitroimidazo[1,2-a]pyridine

Product 1

HCID 541686243-Formyl-2-methyl-8-nitro-imidazo[1,2-a]pyridine

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
70 °C

Procedure

20 ml phosphoroxychloride is added dropwise within 5 minutes to a solution of 7.6 g 2-methyl-8-nitro-imidazo[1,2-a]pyridine in 100 ml dimethylformamide at 0° C. After stirring for 1 hour at 0° C. and for 2 hours at 70° C. the mixture is cooled again to 0° C. 10 ml phosphoroxychloride is added dropwise and the same procedure is carried out as before. When the reaction is finished the mixture is poured over 200 ml icewater, neutralized with saturated sodium hydrogen carbonate solution and extracted 3×with 50 ml ethyl acetate each time. The solvent is stripped off in vacuo and the residue is washed with ether and recrystallized from acetronitrile, giving the title compound of m.p. 188°-189° C.

Workup

  1. temperatureis cooled again to 0° C
  2. additionis poured over 200 ml icewater
  3. extractionextracted 3×with 50 ml ethyl acetate each time
  4. washthe residue is washed with ether
  5. customrecrystallized from acetronitrile

Sources & evidence

ORD record
ord-7b230e6d684945e29c5c39dd437c2c9a
Source dataset
uspto-grants-1992_05
Patent number
US05112834

Reaction notes

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