Hydrochloric Acid → 1-(Pyrazin-2-yl)ethanamine

Participants

Reaction Steps

To a solution of 2-acetylpyrazine (206.7 mg, 1.7 mmol) and ammonium acetate (1.3 g, 17 mmol) in methanol (5.0 mL) was added sodium cyanoborohydride (75 mg, 1.19 mmol) followed by 3 Å molecular sieves (0.85 g). The reaction mixture was stirred for 1 day at room temperature. It was acidified to pH 2 with concentrated HCl then filtered, and the solid was washed with methanol and H2O. The filtrate was concentrated in vacuo. The residue was dissolved in water and was made basic (pH 10-12) with 5N NaOH. The aqueous layer was extracted with CH2Cl2 several times while maintaining ˜pH 10. The combined extracts were dried over Na2SO4, filtered, and concentrated the solvent in vacuo. The crude product was purified by preparative thin layer chromatography eluting with 5% 2M NH3 in MeOH/CH2Cl2 to give 74 mg of the title compound. 1H NMR (500 MHz, CDCl3): 8.61 (s, 1H); 8.5 (d, J=1.6 Hz, 1H); 8.44 (d, J=1.6 Hz, 1H); 4.21 (q, J=6.8 Hz, 1H); 1.46 (d, J=6.8 Hz).

Provenance & Evidence