5-Methoxy-2-pyrazinecarboxylic acid

Step 2: Preparation of 5-methoxypyrazine-2-carboxylic acid [0171] To a solution 5-chloropyrazine-2-carboxylic acid (7 g, 44.15mmol) in methanol (55 mL) was added concentrated sulphuric acid (0.4 mL) and heated at 65 °C for 4 h. The reaction mixture was cooled to room temperature and diluted with methanol (15 mL). Then a solution of sodium methoxide in methanol (8.58 g , 158.94 mmol, 35 mL) was added and the reaction mixture was stirred at room temperature for 30 minutes. Sodium hydroxide (2.825 g , 70.643mmol) in 30 ml water was added into the reaction mixture followed by addition of 40 mL water. Then the reaction mixture was heated at 40 °C for 1 h and concentrated to remove methanol. The residue was diluted with water, acidified with 38percent aqueous hydrochloric acid solution (pH 2-3) and extracted ethyl acetate (600 mL x 3). The combined organic layer was dried over anhydrous sodium sulfate, filtered and concentrated to afford the title compound 5-methoxypyrazine-2-carboxylic acid (6.43 g, 94percent yield) as an orange solid. Calculated M+H: 155.04; Found M+H: 155.1.Example 75-Methoxypyrazine-2-carboxylic acidA 185 ml stirred autoclave was charged under argon with PdC12(dppp) (508 mg, 0.844 mmol), 2- bromo-5-methoxypyrazine (8.40 g, 42.2 mmol), tert-butanol (35 ml), deionized water (45 ml) and triethylamine (10.7 g, 0.106 mol, 2.5 molar equivalents). The reaction vessel was closed, purged three times with carbon monoxide (15 bar) and finally charged with carbon monoxide to 10 bar. The mixture was stirred vigorously at 60°C under constant pressure for 48 h; after thistime no more carbon monoxide absorption was observed.The reaction mixture was concentrated on a rotary evaporator under simultaneous addition of water in order to remove the volatile organic components. The resulting aqueous phase was extracted twice with dichloromethane. After filtration, the pH of the solution was reduced under stirring to ca. 1 by dropwise addition of hydrochloric acid. The resulting suspension was storedat 4°C over night and then filtered. The filter cake was rinsed with water and dried in vacuo to constant weight to afford 5-methoxypyrazine-2-carboxylic acid (5.9 g) as a white solid, MS: mlz= 155.2 [M+Hj.

Molecular Weight:154.12
XLogP3:-0.1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:2
Exact Mass:154.03784206
Monoisotopic Mass:154.03784206
Topological Polar Surface Area:72.3
Heavy Atom Count:11
Complexity:151
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes