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Published TCIMAIL newest issue No.198
Maximum quantity allowed is 999
We are proud to introduce the Suzuki-Miyaura cross coupling of heteroaryl chloride and arylboronic acid by using PdCl2(Amphos)2 as a catalyst. This reaction proceeds even if the substrate has an unprotected amino group.
To a reaction vessel, 3-amino-2-chloropyridine (0.8 g, 6.2 mmol), 2-methylphenylboronic acid (1.0 g, 7.4 mmol, 1.2 eq.), PdCl2(Amphos)2 (0.044 g, 0.062 mmol, 1 mol%), potassium carbonate (1.3 g, 9.4 mmol, 1.5 eq.), toluene (20 mL), and ion-exchange water (2 mL) were sequentially added. Under N2 atmosphere, the reaction mixture was refluxed at 90 °C for 5 hours. The reaction was monitored by TLC and after the reaction mixture was cooled at room temperature, water (20 mL) was added and extracted with ethyl acetate. The organic layer was washed with 1 mol/L NaOH aq and brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduce pressure and the given crude product was purified by silica gel column chromatography (hexane:ethyl acetate = 1:1) to obtain 2-(o-tolyl)-3-pyridinamine (0.90 g, 79% yield) as a milky white powder.
The reaction mixture was monitored by TLC (hexane:ethyl acetate = 1:1, Rf = 0.4).
2-(o-tolyl)-3-pyridinamine
1H NMR (400 MHz, CDCl3); δ 8.06 (d, 1H, J = 2.7 Hz), 8.05 (d, 1H, J = 2.7 Hz), 7.34-7.27 (m, 4H), 7.13-7.10 (m, 2H), 3.70 (brs, 2H), 2.18 (s, 3H).