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. 24241-18-7, name is 2-Amino-3,5-dibromopyrazine, A new synthetic method of this compound is introduced below., 24241-18-7
Magnesium turnings (293.9mg, 12.1mmol, 3.0equiv) and I2 (153.6mg, 605mumol, 0.15equiv) were added to a dry 100-mL 2-necked round-bottom flask under an argon atmosphere. Freshly distilled THF (25mL) was added using a syringe. The mixture was stirred at 0¡ãC until the brown color of the I2 disappeared. Then, benzylbromide (1.44mL, 12.1mmol, 3.0equiv) was slowly added using a syringe. After 10min ZnCl2 was added and the mixture was stirred for 40min. To this mixture, bis(triphenylphosphine)palladium (II) dichloride (141.8mg, 0.20mmol, 0.05equiv) and a solution of 2-amino-3,5-dibromopyrazine (1.02g, 4.03mmol, 1.0equiv) in dry THF (25mL) were added sequentially at room temperature. The resulting orange-colored reaction mixture was stirred for 3 days at room temperature and then quenched with water (50mL) at 0¡ãC. The mixture was diluted with ethyl acetate (300mL) and water (100mL). The organic layer was separated and the aqueous layer was extracted with ethyl acetate (4¡Á200mL). The combined organic layers were dried over anhydrous Na2SO4 and concentrated on a rotary evaporator. The residue was dissolved in CH2Cl2 and purified by silica gel column chromatography (gradient elution: PE?EtOAc, 85:15?65:35) to afford compound 11 (738.2mg, 2.79mmol, 70percent) as viscous yellow oil. Rf=0.46 (silica gel, PE?EtOAc, 7:3); 1H NMR (400MHz, CDCl3): delta=7.93 (s, 1H), 7.26?7.21 (m, 2H), 7.20?7.15 (m, 1H), 7.15?7.10 (m, 2H), 4.40 (br s, 2H), 3.99 (s, 2H); 13C NMR (100MHz, CDCl3): delta=152.3, 142.6, 141.9, 135.8, 129.2, 128.6, 127.4, 126.4, 40.9; IR (neat): numax=3472, 3314, 3200, 3060, 3027, 2919, 2850, 1605, 1555, 1529, 1494, 1424, 1389, 1340, 1261, 1220, 1158, 1117, 1073, 1048, 1028, 1002, 923, 905, 791, 759, 726, 696, 634cm?1; HRMS (ESI): calcd for C11H1179BrN3+ 264.0131; found 264.0133; calcd for C11H1181BrN3+ 266.1414; found 266.0113. The spectroscopic data are in good agreement with those reported in the literature.11d
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:
Article; Vece, Vito; Vuocolo, Giuseppina; Tetrahedron; vol. 71; 46; (2015); p. 8781 – 8785;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem