A CONVENIENT SYNTHESIS OF OTHERWISE INACCESSIBLE 3-AMINOCINNOLINE-4-CARBOXYLIC ACID-DERIVATIVES

3-Amino-4-(2-nitroaryl)-2H-isoxazolin-5-ones, readily available by the sodium ethoxide catalysed cyclisation of amidoximes derived from ethy l 2-cyano-2-(2-nitroaryl)acetates, ring-close in the presence of sodiu m hydride to afford high yields of isoxazolo[3,4-c]cinnolin-1 (3H)-one 5-N-oxides; hydrazine effects the chemoselective reductive scission o f the isoxazoline ring in these heterocycles allowing simple and effic ient synthetic access to erstwhile unavailable 3-aminocinnoline-4-carb oxylic acid 1-N-oxides.