Reference of 5521-55-1, A common heterocyclic compound, 5521-55-1, name is 5-Methylpyrazine-2-carboxylic acid, molecular formula is C6H6N2O2, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Step 1. tert-butyl 5-methylpyrazin-2-ylcarbamate To solution 5-methylpyrazine-2-carboxylic acid (2.5 g, 18.1 mmol), tert-butanol (6.92 mL, 72.4 mmol), Et3N (3.78 mL, 27.1 mmol) in 1,4-dioxane (12.5 mL) at 95 C. was dropwise added diphenylphosphoryl azide (DPPA, 3.23 mL, 18.1 mmol), and the reaction was heated at 95 C. for 1.5 h, followed by a 2nd portion of DPPA (1 mL, 5.6 mmol) and heated for additional 1.5 h. The reaction mixture was cooled down, concentrated and the residue was diluted with EtOAc (50 mL), washed with water (30 mL), 3 M NaOH (30 mL), sat. NaHCO3 (30 mL) and brine (30 mL), dried over Na2SO4, and concentrated. The residue was purified by flashed chromatography on silica gel eluting with gradient EtOAc/CH2Cl2 (0-20%) to afford tert-butyl 5-methylpyrazin-2-ylcarbamate as white solid. LCMS (m/z): 210.1 (MH+), 0.69 min; 1H NMR (400 MHz, CDCl3) delta ppm 9.17 (s, 1H), 8.09 (s, 1H), 7.75 (br. s., 1H), 2.51 (s, 3H), 1.56 (s, 9H).
The synthetic route of 5521-55-1 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Novartis AG; Bagdanoff, Jeffrey T.; Ding, Yu; Han, Wooseok; Huang, Zilin; Jiang, Qun; Jin, Jeff Xianming; Kou, Xiang; Lee, Patrick; Lindvall, Mika; Min, Zhongcheng; Pan, Yue; Pecchi, Sabina; Pfister, Keith Bruce; Poon, Daniel; Rauniyar, Vivek; Wang, Xiaojing Michael; Zhang, Qiong; Zhou, Jianguang; Zhu, Shejin; (366 pag.)US9242996; (2016); B2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem