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

HRID 1729398Notes

Reaction equation

HRID 1729398 reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[C:6]([CH3:9])[CH:5]=[CH:4][N:3]=1.[NH4+].[OH-]>>[CH3:9][C:6]1[CH:5]=[CH:4][N:3]=[C:2]2[N:1]=[C:4]([CH2:5][CH2:6][CH3:7])[NH:8][C:7]=12

Participants

3

Reactant 2

HCID 14923Ammonium HydroxideHCID 3174954-Methylpyridine-2,3-diamine

Product 1

HCID 150208527-Methyl-2-propyl-1H-imidazo[4,5-b]pyridineYield 174.5%

Conditions

Temperature
100 °C

Procedure

A mixture of burytic acid (6.57 mL, 71.9 mmol), 2,3-diamino-4-picoline (8.05 g, 65.4 mmol) (Lappin, G. R., Slezak, F. B. J. Am. Chem. Soc. (1950) 72, 7806-7) and polyphosphoric acid (50 g) was heated to 100° C. with stirring for 3 hours. The reaction was monitored by tlc of NH4OH neutralized aliquots. Basification (NH4OH), extraction (CH2Cl2, 4×50 mL), drying (K2CO3), purification (by filtering through 100 g SiO2, EtOAc elution), and concentration gave 10.0 g (95%) of the title compound as an amorphous tan solid which was judged pure by 1H NMR and tlc: mp 110°-112 ° C. (without recrystallization); 1H NMR (300 MHz, CDCl3) δ 8.13 (d, 1H, J=5 Hz), 7.01 (d, 1H, J=5 Hz), 3.01 (t, 2H, J=7.8 Hz), 2.67 (s, 3H), 2.07-1.93 (m, 2H), 1.06 (t, 3H, J=7.5 Hz).

Workup

  1. extractionBasification (NH4OH), extraction (CH2Cl2, 4×50 mL)
  2. customdrying
  3. custom(K2CO3), purification (by filtering through 100 g SiO2, EtOAc elution), and concentration

Sources & evidence

ORD record
ord-c802799bc96940b3bcbf1435883a9800
Source dataset
uspto-grants-1994_07
Patent number
US05332744

Reaction notes

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