16298-03-6

yellow crystalline powder

ChEBI: Methyl 3-aminopyrazine-2-carboxylate is a pyrazine that is substituted by a methoxycarbonyl group at position 2 and an amino group at position 3. It is a member of pyrazines, a methyl ester and an aromatic amine.

General procedure for the synthesis of methyl 3-aminopyrazine-2-carboxylate from methanol and 3-aminopyrazine-2-carboxylic acid: 3-aminopyrazine-2-carboxylic acid (5 g, 1 eq.) was added to methanol (50 ml) followed by the slow addition of concentrated sulphuric acid (4 eq.) under ice-water bath conditions. The reaction mixture was stirred at room temperature and the progress of the reaction was monitored by thin layer chromatography (TLC) until completion of the reaction. Upon completion of the reaction, the reaction solution was concentrated and the pH was adjusted with saturated sodium carbonate solution to 8. The precipitate was collected by filtration and dried at 50 °C for 2 h to afford methyl 3-aminopyrazine-2-carboxylate as a brown solid (4.18 g, 76% yield).

Store at -20°C

The ester forms yellow needles from H2O (100 parts using charcoal). If it contains the free acid (see IR), then dissolve it in CH2Cl2, wash it with saturated aqueous Na2CO3, brine, dry over MgSO4 filter, evaporate and recrystallise the residue. The free acid has m 203-204o (dec) [UV: Brown & Mason J Chem Soc 3443 1956] and pK1 <1 and pK2 3.70. The ammonium salt has m 232o(dec) (from aqueous Me2CO) and the amide has m 239.2o (from H2O) [Ellingson et al. J Am Chem Soc 67 1711 1945]. [Beilstein 25 III/IV 4412.]

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