Some common heterocyclic compound, 109-08-0, name is 2-Methylpyrazine, molecular formula is C5H6N2, 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. name: 2-Methylpyrazine
General procedure: An oven-dried flask was purged with argon while hot, then allowed to cool down to room temperature under argon and charged with dry THF (2 mL/mmol of starting indole 3/6) and diisopropylamine (4.0 equiv). The solution was cooled to -78 ¡ãC in a dry ice/isopropanol bath and n-butyl lithium, 1.6 M solution in hexanes (4.0 equiv), was added to give a bright yellow solution. The mixture was stirred for 30 min below -60 ¡ãC whereupon a solution of picoline or another appropriate reagent with an ionizable methyl(ene) group (4.0 equiv) in THF (2 mL/mmol of starting indole 3 or 6) was added to give a yellow to red colored mixture. During a further 30 min, the bath temperature was allowed to rise to approx. 0 ¡ãC during which time the reaction mixture became a yellow to red suspension. The temperature was then kept at 0 ¡ãC (using an ice/water bath) for an additional 30 min. At this point, a solution of the indole-2-carbonyl compound 3/6 (1.0 equiv) in THF (4 mL/mmol) was added dropwise over the flask wall. The reaction mixture darkened (dark purple to dark brown color in most cases) and was then allowed to attain room temperature overnight. At 18 h (unless otherwise stated) after the addition of the indole component, the reaction was quenched with saturated aqueous ammonium chloride solution (10 mL/mmol of starting compound 3/6) and stirred for several minutes. Upon partition between ethyl acetate and water, the aqueous phase was extracted twice with dichloromethane and the combined organic layers were dried over MgSO4. The title products were purified by chromatography (the products typically eluted with 70-80percent of ethyl acetate). The products were then precipitated by concentration of the pooled column fractions combined with the addition of cyclohexane. The precipitates formed were filtered off, washed twice with cyclohexane and dried at 40 ¡ãC in vacuo to yield analytically pure samples. The following compounds were prepared in this way:
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 109-08-0, its application will become more common.
Reference:
Article; Dolusic, Eduard; Larrieu, Pierre; Blanc, Sebastien; Sapunaric, Frederic; Norberg, Bernadette; Moineaux, Laurence; Colette, Delphine; Stroobant, Vincent; Pilotte, Luc; Colau, Didier; Ferain, Thierry; Fraser, Graeme; Galeni, Moreno; Frre, Jean-Marie; Masereel, Bernard; Van Den Eynde, Benoit; Wouters, Johan; Frederick, Raphael; Bioorganic and Medicinal Chemistry; vol. 19; 4; (2011); p. 1550 – 1561;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem