3-Amino-4-(2-nitroaryl)-2H-isoxazolin-5-ones, readily available by the sodium ethoxide catalysed cyclisation of amidoximes derived from ethyl 2-cyano-2-(2-nitroaryl)acetates, ring-close in the presence of sodium hydride to afford high yields of isoxazolo[3,4-c]cinnolin-1(3H)-one 5-N-oxides; hydrazine effects the chemoselective reductive scission of the isoxazoline ring in these heterocycles allowing simple and efficient synthetic access to erstwhile unavailable 3-aminocinnoline-4-carboxylic acid 1-N-oxides.
3-
氨基-4-(2-硝基芳基)-2H-
异噁唑啉-5-酮很容易通过
乙醇钠催化环化 2-
氰基-2-(2-硝基芳基)
乙酸乙酯衍生的脒氧
肟而获得,在氢化
钠存在下环状闭合,可获得高产率的
异噁唑并[3,4-c]噌啉-1(3H)-酮 5-N-氧化物;
肼可使这些杂环中的
异噁唑啉环发生
化学选择性还原裂解,从而简单高效地合成出以前无法获得的 3-
氨基
噌啉-4-羧酸 1-N-氧化物。