Nitrolic acids: efficient precursors of nitrile oxides under neutral conditions

Nitrolic acids are prepared in good yields from primary nitroalkanes or pri mary alkyl bromides. Upon heating in THE they afford the corresponding nitr ile oxides under neutral conditions. In the presence of dipolarophiles, iso xazoles are obtained in yields up to 95%. For the less stable alkoxycarbony l- and arylnitrolic acids the crude nitrolic acids can be directly engaged in the cycloaddition reaction. (C) 2000 Elsevier Science Ltd. All rights re served.