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

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).

1. filtrationthen filtered
2. washthe solid was washed with methanol and H2O
3. concentrationThe filtrate was concentrated in vacuo
4. dissolutionThe residue was dissolved in water
5. extractionThe aqueous layer was extracted with CH2Cl2 several times
6. temperaturewhile maintaining ˜pH 10
7. dry with materialThe combined extracts were dried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated the solvent in vacuo
10. customThe crude product was purified by preparative thin layer chromatography
11. washeluting with 5% 2M NH3 in MeOH/CH2Cl2

ORD record

ord-82dae7df549e457aac72c7484412383f

Source dataset

uspto-grants-2002_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06498165B1