The chemistry of cycloheptatriene, part XIII : thermal fragmentation of 7-dimethylaminocycloheptatriene to benzene and dimethylaminocarbene ; preliminary communication

cf. CA 3311c. 7-(Dimethylamino)cycloheptatriene (I) was heated and isomerized to give II and finally III. In addn. were also isolated 5-8% C6H6 and a compd. C8H8(NMe2)2 (IV), b0.3 57 Deg. The following mechanism is offered: I -> C6H6 + CHNMe2; I + CHNMe2 -> IV. On the basis of the N.M.R. spectral studies IV is given the structure shown. Structure IV was also proved chem. Reaction of IV with 1 mole MeI followed by Hofmann degradation yielded 1-(dimethylamino)heptafulvene, which on further reaction with MeI, Hofmann degradation, and hydrogenation gave methylcycloheptane. [on SciFinder (R)]