Heterocyclic Rearrangement of 4,5,6,7‐Tetrahydro‐6,6‐dimethyl‐benzo[c][1,2,5]oxadiazol‐4‐one (Z)‐Arylhydrazones into Corresponding 2‐Aryl‐4,5,6,7‐tetrahydro‐2H‐benzo[d][1,2,3]triazol‐4‐one Oximes

Abstract

182. Heterocyclic Rearrangement of 4,5,6,7-Tetrahydro-6,6-dimethylbenzo[c] [ 1,2,5]oxadiazol-4-one (Z)-Arylhydrazones into Corresponding 2-Aryl-4,5,6,7-tetrahydro-2H-benzo[d] [ 1,2,3]triazo1-4-one Oximes The thermal base-catalysed and photochemical transformation (Boulton-Kutritzky rearrangement) of the title tetrahydrobenzo[c][l,2,5]oxadiazoles to tetrahydro-2H-benzo[d] [1,2,3]triazoles is studied. Attempts to induce analogous rearrangement in tetrahydro-2H-benzo[d] [ 1,2,3]triazol-4-one arylhydrazones or oximes failed. Some CND0/2 calculations are also carried out.We have reported previously [ 13 [2] that attempts to induce thermal or photochemical mononuclear heterocyclic rearrangement in 2-aryl-4,5,6,7-tetrahydro-6,6-dimethyl-2Hbenzo[d] [ 1,2,3]triazo1-4-one (Z)-arylhydrazones were unsuccessful. This prompted us to a more systematic study in order to examine whether this unsuccessful rearrangement [3] i Z; either due to the thermodynamical stability of the triazole ring [4] [5] or to an unfavored geometry of the condensed ring system.The present study is concerned with Boulton-Katritzky-type rearrangements [6] [7] of 4,5,6,7-tetrahydro-6,6-dimethylbenzo[c] [ 1,2,5]oxadiazo1-4-one (Z)-arylhydrazones (2) to the corresponding 2-aryl-4,5,6,7-tetrahydro-2H-benzo[d] [ 1,2,3]triazo1-4-one oximes (3). Comparatively few examples of ring transformations of 1,2,5-0xadiazoles to 1,2,3-Scheme I