抄録
3, 4-Dihydro-1-methyl-6-phenyl-1, 4, 5-benzotriazocin-2 (1H)-one (1a) readily undergoes a transformation into 1-(methylcarbamoyl) methyl-3-phenyl-1H-indazole (3a) when its chloroform solution is kept at room temperature. The 8-chloro, 8-bromo and 8-fluoro derivatives of 1a (1b, 1c and 1d) similarly afford the corresponding 5-halogenoindazoles (3b, 3c and 3d), but 3, 4-dihydro-6-phenyl-1, 4, 5-benzotriazocin-2 (1H)-one, and its 1-benzyl and 1-dialkylaminoalkyl derivatives give no ring contraction product under the same conditions.
