Rearrangement of 3,3-Disubstituted 1-Aryl-4,5-dihydro-5-oxo-3<i>H</i>-1,2,4-triazolium Tetrafluoroborates; Part 2. A Convenient Synthesis of 1,5-Annulated 1,2-Dihydro-2-phenyl-3<i>H</i>-1,2,4-triazol-3-ones
作者:Hubert Gstach、Patrick Seil
DOI:10.1055/s-1990-27022
日期:——
1-Isocyanato-1-(phenylazo)cycloalkanes 3 react with tetrafluoroboric acid to yield 3-spiro substituted 4,5-dihydro-5-oxo-1-phenyl-3H-1,2,4-triazolium tetrafluoroborates 4. Compounds 4 rearrange with ring expansion in good yield to give, after basic workup, 1,5-annulated 1,2-dihydro-2-phenyl-3H-1,2, 4-triazol-3-ones 5.
1-异氰酸基-1-(苯偶氮)环烷与四氟硼酸反应,生成3-螺取代的4,5-二氢-5-氧代-1-苯基-3H-1,2,4-三唑鎓四氟硼酸盐4。化合物4通过环扩张重排,在碱性后处理条件下,以良好产率得到1,5-并环的1,2-二氢-2-苯基-3H-1,2,4-三唑-3-酮5。