3-Substituted 2-isoxazolines or isoxazoles were obtained from the reaction of primary nitro compounds [methyl nitroacetate, 2-nitro-1-phenylethanone,(nitromethyl) benzene, 1- nitropropane, and (phenylsulfonyl) nitromethane] with dipolarophiles in refluxing mesitylene in the presence of a small amount of p-toluenesulfonic acid. The formation of these products can be explained in terms of 1, 3-dipolar cycloaddition of nitrile oxide generated by a ...
