These common heterocyclic compound, 2423-65-6, name is Pyrazine 1-oxide, 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. name: Pyrazine 1-oxide
General Procedure 2:; Palladium-Catalyzed Direct Arylation with Aryl Chlorides and Bromides.; To a dried flask was added the diazine N-oxide (1.0 to 3.0 equiv.), K2CO3 (2.0 equiv.), Pd(OAc)2 (5 mol %) and HP(t-Bu)3BF4 (15 mol %). If the arylhalide is a solid, it is added at this point (1.0 equiv.). The flask and its contents were then purged under nitrogen for 10 minutes. If the aryl halide is a liquid, it is added via syringe after purging, followed by the addition of degassed dioxane (to produce a reaction concentration of 0.3 M relative to the halide). The reaction mixture was then heated at 110 C. until the reaction was complete, after which the volatiles were removed under reduced pressure and the residue was purified via silica gel column chromatography.; 2-p-Tolylpyrazine N-oxide (81) Synthesised according to general procedure 2 employing the corresponding aryl bromide and chloride or 60 with the corresponding aryl iodide. Purification via silica gel column chromatography using 100% DCM then a mixture of 20% Acetone/DCM gave a white solid, 72% (from the bromide), 75% (from the chloride) and 77% (from the iodide). 1H NMR (300 MHz, CDCl3, 293K, TMS): delta 8.63 (1H, s), 8.37 (1H, s), 8.20 (1H, s), 7.72 (2H, d, J=8.1 Hz), 7.33 (2H, d, J=7.8 Hz), 2.43 (3H, s). 13C NMR (75 MHz, CDCl3, 293K, TMS): 148.2, 145.2, 144.6, 140.8, 134.2, 129.8, 129.0, 125.9, 21.5.
The synthetic route of Pyrazine 1-oxide has been constantly updated, and we look forward to future research findings.
Reference:
Patent; University of Ottawa; US2008/132698; (2008); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem