Studies on Pyrazines; Part 30:<sup>1</sup>Synthesis of Aminopyrazines from Azidopyrazines
作者:Nobuhiro Sato、Tomoyuki Matsuura、Naoko Miwa
DOI:10.1055/s-1994-25607
日期:——
Azidopyrazines do not undergo reduction by reagents that are effective for the preparation of alkyl- or arylamines from the azides because the heterocyclic azides exist in the bicyclic form of tetrazolo[1,5-a]pyrazines. Nevertheless, the conversion into aminopyrazines was achieved by hydrogenolysis in the presence of ammonium hydroxide and palladium-on-carbon or particularly by reduction with tin(II) chloride in methanolic hydrochloric acid, in 34-87% yields. To elucidate the successful progress of the reaction, the equilibrium of azide-tetrazole was examined by 1H NMR spectroscopy in various solvents.
叠氮吡嗪不能通过有效制备烷基或芳基胺的试剂进行还原,因为杂环叠氮化物以双环形式存在于四唑[1,5-a]吡嗪中。然而,通过在氨 hydroxide 和钯-炭存在下进行加氢裂解,或通过在醇溶盐酸中用氯化锡(II)还原,成功转化为氨基吡嗪,产率为34-87%。为了阐明反应的成功进展,通过1H NMR光谱在不同溶剂中检查了叠氮-四唑的平衡。