Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 41110-29-6, name is Methyl 3-methylpyrazine-2-carboxylate, A new synthetic method of this compound is introduced below., COA of Formula: C7H8N2O2
A solution of methyl 3-methylpyrazine-2-carboxylate (9.1 g, 59.8 mmol) in DCM (100 mL) was cooled to 0 C. was added urea hydrogen peroxide adduct (7.8 g, 83.0 mmol), followed by dropwise addition of trifluoroacetic acid anhydride (10.8 mL, 78.0 mmol). The resulting mixture was stirred at 0 C. for 1 h, and at RT for 18 h, during which LCMS indicated a mixture of two peaks corresponding to MS m/z=169.0 [M+H]+. The reaction was diluted with DCM and quenched with saturated Na2SO3 solution; the aqueous layer was back-extracted with DCM (2×). The combined organic extracts were dried (MgSO4), filtered and concentrated in vacuo. ISCO purification (20-80% EtOAc/hexanes) afforded a mixture of two regioisomers, containing 3-(methoxycarbonyl)-2-methylpyrazine 1-oxide and 2-(methoxycarbonyl)-3-methylpyrazine 1-oxide (5.2 g, 30.9 mmol, 51.7% yield). The mixture of regioisomers was taken to next step without further purification. MS m/z=169.0 [M+H]+. A solution of the mixture of 3-(methoxycarbonyl)-2-methylpyrazine 1-oxide and 2-(methoxycarbonyl)-3-methylpyrazine 1-oxide (5.1 g, 15.2 mmol) in toluene (50 mL) was cooled to 0 C. and phosphorus oxychloride (2.8 mL, 30.3 mmol) was added under nitrogen followed by DMF (0.12 mL, 1.52 mmol). The reaction mixture was stirred at RT for 4 h, and heated to 65 C. for 18 h, cooled to RT, diluted with EtOAc and washed with saturated NaHCO3 solution. The aqueous layer was back-extracted with EtOAc (2×). The combined organic extracts were dried (MgSO4), filtered and concentrated in vacuo. ISCO purification (0-50% EtOAc/hexanes) with care afforded both isomers: methyl 5-chloro-3-methylpyrazine-2-carboxylate (0.68 g) (minor product) denoted by peak 1 and methyl 6-chloro-3-methylpyrazine-2-carboxylate (1.50 g) (major product) denoted by peak 2. MS m/z=187.0 [M+H]+. Peak 1: 1H NMR (300 MHz, DMSO-d6) delta 8.73 (s, 1H), 3.91 (s, 3H), 2.71 (s, 3H). Peak 2: 1H NMR (300 MHz, DMSO-d6) delta 8.89 (s, 1H), 3.91 (s, 3H), 2.71 (s, 3H).
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Patent; LEWIS, Richard T.; ALLEN, Jennifer R.; BROWN, James; GUZMAN-PEREZ, Angel; HUA, Zihao; JUDD, Ted; LIU, Qingyian; OLIVIERI, Philip R.; ROMERO, Karina; SCHENKEL, Laurie; STELLWAGEN, John; WHITE, Ryan; US2015/38497; (2015); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem