2-Pyrazinecarboxylic acid, 3-amino-, methyl ester

yellow crystalline powder

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.

Compound 1 (5 g, leq) was added to methanol (50 ml)Ice water bath by adding concentrated sulfuric acid (4eq), The reaction was stirred at room temperature, TLC showed complete reaction, concentrate, Saturated sodium carbonate adjusted to pH = 8, Filter, 50 dry 2h, A brown solid 2 (4.18 g, 76percent).To a suspension of 3-aminopyrazine-2-carboxylic acid(20 g, 1 eq) in methanol (200 mL) in an ice bath, concentratedH2SO4 (20 mL) was added slowly (dropwise, over at least a 2 h interval). After vigorous stirring for48 h, a black solution was formed and TLC (EA:PE = 1:2, v/v, Rf = 0.22) analysis showed the complete consumptionof compound 1. The reaction mixture was then concentrated.The mixture was adjusted to pH 7–8 by progressivelyadding Na2CO3 (20percent, m/m) aqueous solution(100 mL) under ice conditions. The mixture was filtered.The filter residue was collected and dried under reducedpressure to obtain black solid 2 (15.4 g, 70percent).Methyl 3-aminopyrazine-2-carboxylate (2)Yield: 70percent, black solid. m.p.: 173–175 C (Lit.172–173 C, Caldwell et al. 2012). 1H-NMR (400 MHz, DMSO-d6): d 8.26 (d, J = 2.2 Hz, 1H), 7.90 (d, J = 2.2 Hz, 1H), 7.37–7.32 (m, 2H), 3.84 (s, 3H). 13C NMR (101 MHz, DMSO-d6): d 166.37, 155.78, 147.72, 132.40, 123.12, 52.00. MS (EI): m/z = 153.1 (M?). 94.1(M?, –COOCH3).Example 1139.1 1 153.14[0257] A slurry of 3-amino-2-pyrazinecarboxylic acid (15 gm, 0.108 moles) in dry methanol (250 mL) was stirred as concentrated sulfuric acid (10 mL, 18.4 gm, 0.188 moles) was added. The addition of the acid caused most of the solid to dissolve. The mixture was stirred at reflux, causing the formation of a clear yellow solution. This solution was stirred at reflux for 5 hours and was then stored at room temperature overnight. The solution was diluted with methylene chloride (500 mL) and was stirred as a solution of potassium carbonate (26 gm, 0.188 moles) in water (75 mL) was slowly added. After stirring for 15 minutes, the organic phase was separated from the aqueous phase and was dried over magnesium sulfate. After filtration to remove the drying agent, the solvents were removed under reduced pressure. The solid residue was recrystallized from isopropyl alcohol to provide the methyl ester as a tan powder in a yield of 7.22 gm (43.7percent).15 g of 3-aminopyrazine-2-carboxylic acid was added to 200 ml of methanol.Add 10 ml of thionyl chloride, stir overnight at room temperature, and concentrate.200 ml of toluene was added and concentrated to give 18 g of 3-aminopyrazine-2-carboxylic acid methyl ester.EXAMPLE 74

Molecular Weight:153.14
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:2
Exact Mass:153.053826475
Monoisotopic Mass:153.053826475
Topological Polar Surface Area:78.1
Heavy Atom Count:11
Complexity:151
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes