6-Amino-2,2'-bipyridine

Synthesis

The general procedure for the synthesis of 6-amino-2,2'-bipyridine from 6-bromo-2,2'-bipyridine was as follows: a mixture of 6-bromo-2,2'-bipyridine (3.0 mmol, 705 mg) and Cu2O (0.01 mmol, 1.0 mg) in ethylene glycol was added to an autoclave. The reaction system was charged with NH3 to 10 atm at a pressure of 110 atm. After completion of the reaction, the mixture was cooled to room temperature, water was added and the aqueous phase was extracted with dichloromethane (DCM). The organic layers were combined, washed with saturated brine and dried over anhydrous MgSO4. After evaporation of the solvent under reduced pressure, the crude product was purified by column chromatography using silica gel as stationary phase and hexane:ethyl acetate (1:1) as eluent to give a white solid product (437 mg, 85% yield). The structure of the product was confirmed by 1H NMR (500 MHz, CDCl3) and 13C NMR (125 MHz, CDCl3): 1H NMR (500 MHz, CDCl3, ppm): δ 8.65 (s, 1H), 8.25 (d, 1H, J = 7.9 Hz), 7.79-7.76 (m, 1H), 7.71- 7.70 (m, 1H), 7.57 (t, 1H, J = 7.1 Hz), 7.26 (t, 1H, J = 7.1 Hz), 6.65 (d, 1H, J = 7.9 Hz), 4.53 (br, 2H); 13C NMR (125 MHz, CDCl3, ppm): δ 157.97, 156.38, 154.57, 149.11, 138.58 149.11, 138.58, 136.73, 123.31, 120.94, 111.59, 108.87.

References

[1] Patent: US2012/323007, 2012, A1. Location in patent: Page/Page column 13
[2] Organometallics, 2014, vol. 33, # 15, p. 4152 - 4155
[3] Journal of the American Chemical Society, 2018, vol. 140, # 39, p. 12451 - 12456
[4] Journal of the Chemical Society, 1938, p. 1662,1669