[Synthesis]
General steps for the synthesis of 5-phenylpyridine-3-carbaldehyde:
1. reaction mixture preparation: 5-bromopyridine-3-carboxaldehyde (0.500 g, 2.69 mmol), tetrakis(triphenylphosphine)palladium (0.155 g, 0.134 mmol), and phenylboronic acid (0.492 g, 4.03 mmol) were dissolved in a biphasic mixture of degassed 2.0 M aqueous Na2CO3 solution (6.0 mL) and toluene (6.7 mL).
2. Reaction conditions: the mixture was heated to reflux for 2.5 hours.
3. Post-treatment: After completion of the reaction, the mixture was cooled to room temperature and diluted with water and ethyl acetate (EtOAc). The organic and aqueous layers were separated and the aqueous layer was extracted with ethyl acetate (1x). The organic layers were combined, washed with brine, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated to give an orange-brown oil (0.848 g).
4. Purification: 5-phenylpyridine-3-carbaldehyde (0.447 g, 91% yield) was purified by silica gel column chromatography as a light yellow solid.
5. Characterization: 1H NMR (500MHz, CDCl3) δ: 10.19 (s, 1H), 9.07 (s, 1H), 9.04 (s, 1H), 8.34 (s, 1H), 7.62 (d, J = 7.7Hz, 2H), 7.52 (t, J = 7.7Hz, 2H), 7.47-7.44 (m, 1H). Mass spectrum (MS): 184.2 (M + H)+; 216.2 (M + CH3OH + H)+. |
[References]
[1] Patent: WO2007/70818, 2007, A1. Location in patent: Page/Page column 95 [2] Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences, 2012, vol. 67, # 1, p. 75 - 84 [3] Patent: US2014/296528, 2014, A1. Location in patent: Sheet 4 |