Butyric Acid → 7-Methyl-2-propyl-1H-imidazo[4,5-b]pyridine

HRID 2255553Notes

Reaction equation

HRID 2255553 reaction equation
[C:1](O)(=O)[CH2:2][CH2:3][CH3:4].[NH2:7][C:8]1[C:13]([NH2:14])=[C:12]([CH3:15])[CH:11]=[CH:10][N:9]=1.[NH4+].[OH-]>>[CH3:15][C:12]1[CH:11]=[CH:10][N:9]=[C:8]2[N:7]=[C:1]([CH2:2][CH2:3][CH3:4])[NH:14][C:13]=12

Participants

4

Reactant 3

HCID 264Butyric AcidHCID 14923Ammonium HydroxideHCID 3174954-Methylpyridine-2,3-diamine

Product 1

HCID 150208527-Methyl-2-propyl-1H-imidazo[4,5-b]pyridineYield 87.3%

Conditions

Temperature
100 °C

Procedure

A mixture of butyric acid (6.57 mL, 71.9 mmol), 2,3-diamino-4-picoline (8.05 g, 65.4 mmol), and polyphosphoric acid (50 g) was heated to 100° C. with stirring for 3 hours, and monitored by tlc of NH4OH neutralized aliquots. Basification (NH4OH), extraction (CH2Cl2, 4×50 mL), drying (K2CO3), purification (by filtering through 100 g silica gel, EtOAc elution), and concentration gave 10.0 g (87%) of the title compound as an amorphous tan solid which was judged pure by 1H NMR and tlc: mp 110°-112° C. (without recrystallization).

Workup

  1. extractionBasification (NH4OH), extraction (CH2Cl2, 4×50 mL)
  2. customdrying
  3. custom(K2CO3), purification (by filtering through 100 g silica gel, EtOAc elution), and concentration

Sources & evidence

ORD record
ord-f5110687667644ce84d84320cb245b20
Source dataset
uspto-grants-1993_08
Patent number
US05240938

Reaction notes

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