α-(Arylazo)alkyl isocyanates 3 react with tetrafluoroboric acid to yield 3, 3-disubstituted 1-aryl-4,5-dihydro-5-oxo-3H-1,2,4-triazo-lium tetrafluoroborates 4. These compounds rearrange under mild conditions and in good yields to the tetrafluoroborates of 1,5 disubstituted 2-aryl-1,2-dihydro-3H-1,2, 4-triazol-3-ones 5. Our results show that the nature of the substituents determines their migratory aptitude for the rearrangement.
α-(芳基氮)烷基
异氰酸酯 3 与四
氟硼酸反应生成 3, 3-取代的 1-芳基-4,
5-二氢-5-氧-3H-1,2,4-三氮鎓四
氟硼酸盐 4。这些化合物在温和条件下以良好的收率重排生成 1,5-双取代的 2-芳基-1,2-二氢-3H-1,2,4-
三氮烯-3-酮的四
氟硼酸盐 5。我们的结果表明,取代基的性质决定了它们在重排中的迁移适应性。