Abstract
Rearrangement of amino group on the seven-membered ring of cycloheptoxazole derivatives was examined. Dimethylamino group in 6-dimethylamino-2-phenyl-6H-cycloheptoxazole (Ia) underwent rearrangement to C-4 and C-8 on standing in a solution, and the ratio of three isomers, Ia, 4-dimethylamino-2-phenyl-4H-cycloheptoxazole (IIa), and 8-dimethylamino-2-phenyl-8H-cycloheptoxazole (IIIa), reached an equilibrium at about 3 : 5 : 2. By the incorporation of dimethylamino-15N into Ia and interchange between the amino group in 6-dimethylamino-2-(2-naphthyl)-6H-cycloheptoxazole (IX), the rearrangement was presumed to take place intermolecularly. 2-(p-Tolyl)-(Ib) and 2-(p-nitrophenyl)-6-dimethylamino-6H-cycloheptoxazole (Ic) also showed similar rearrangement of the dimethylamino group, while the rearrangement was not observed in 2-phenyl-6-(p-toluidino)-6H-cycloheptoxazole (VI) and 5-dimethylamino-5H-benzocycloheptene (VIII).
