Analgesic-active N-alkyl-10-hydroxy-10, 5-(iminomethano)-5H, 10H-and-10-hydroxy-10, 5-(iminomethano)-5H, 10H-dibenzo [a, d] cyclohepten-11-one derivatives (V) were prepared from 5-acylaminomethyl-5H-dibenzo [a, d] cycloheptene via oxidative transannular reaction-lithium aluminium hydride reduction and the transannular reaction-hydrolysis. These derivatives (V) were easily converted by treatment with alkali, alumina and heating to very interesting ring contraction products such as 3, 8-(o-phenylene)-2, 3, 8, 9-tetrahydrobenzo [d] azepin-2-one derivatives. Moreover, an interesting ring opening reaction of the derivatives (V) with acetic anhydride-alkali was examined.
