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., name: Methyl 3-methylpyrazine-2-carboxylate
A solution of methyl 3-methylpyrazine-2- carboxylate (265A, 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 x). 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 x). 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 (265B, 0.68 g) (minor product) denoted by peak 1 and methyl 6-chloro-3-methylpyrazine-2-carboxylate (265B1, 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, 1 H), 3.91 (s, 3H), 2.71 (s, 3H). Peak 2: 1H NMR (300 MHz, DMSO-d6) delta 8.89 (s, 1 H), 3.91 (s, 3H), 2.71 (s, 3H).
The synthetic route of 41110-29-6 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; AMGEN INC.; ALLEN, Jennifer R.; AMEGADZIE, Albert; BOURBEAU, Matthew P.; BROWN, James A.; CHEN, Jian J.; CHENG, Yuan; FROHN, Michael J.; GUZMAN-PEREZ, Angel; HARRINGTON, Paul E.; LIU, Longbin; LIU, Qingyian; LOW, Jonathan D.; MA, Vu Van; MANNING, James; MINATTI, Ana Elena; NGUYEN, Thomas T.; NISHMURA, Nobuko; NORMAN, Mark H.; PETTUS, Liping H.; PICKRELL, Alexander J.; QIAN, Wenyuan; RUMFELT, Shannon; RZASA, Robert M.; SIEGMUND, Aaron C.; STEC, Markian M.; WHITE, Ryan; XUE, Qiufen; (759 pag.)WO2016/22724; (2016); A1;,
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