A Convenient Preparative Method of Nitrile Oxides by the Dehydration of Primary Nitro Compounds with Ethyl Chloroformate or Benzenesulfonyl Chloride in the Presence of Triethylamine
nitrile oxides (MeOCOC≡N→O, PhC≡N→O, and EtC≡N→O) were effectively generated in situ by dehydration of the corresponding primary nitro compounds (RCH2NO2) with PhSO2Cl or ClCOOEt in the presence of triethylamine. Various cycloadducts were prepared by the reaction of them with dipolarophiles. Some advantages of these methods are described in comparison with other known methods.
O-Ethoxycarbonyl hydroximoyl chloride serves as a stable precursor for nitrileoxide and is converted into the 1,3-dipole when heated under reflux in pyridine.
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 nitrileoxide generated by a
approach for the synthesis of isoxazoline derivatives is reported. This protocol involves 1,3-dipolarcycloaddition between in situ generated nitrileoxides from the corresponding aldoximes using [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser’s reagent) and maleimides, styrene and acrylonitrile. The described methodology is very attractive as it is operationally simple, has broad scope, and does not require