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

Participants

Reaction Conditions

Reaction Steps

A mixture of butyric 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) δ8.13 (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).

Provenance & Evidence