Tetrafluorodibenz [b,f][l,4]oxazepin-ll-(10H)-ones have been synthesized and converted to ll-chloro and ll-piperidino substituted polyfluorodibenz [b,f][l,4]oxazepines. Dibenz[b,f][l,4]oxazepines containing a substituted amino group in position ii find use in medicine as neuroleptics and tranquillizers [i]. Their synthesis included intermediate ll-chlorodibenz[b,f][l,4]oxazepines obtained from the corresponding dibenz[b,f][l,4]oxazepinll-(10H)-ones [2].
In this work we have studied the preparation Of polyfluorodibenz[b,f][l,4]oxazepinones and their ll-substituted derivatives.
In the nonfluorinated series of dibenzoxazepinones the most widely used synthetic method is the intramolecular cyclization of 2-hydroxybenzanilides containing a halogen in the 2' position [3]. We have previously shown [4,5] that polyfluoro-2-hydroxybenzylidene anilines readily form dibenz[b,f][l,4]oxazepines upon heating in DMF through intramolecular nucleophilic substitution of the ortho fluorine atom. On this basis we hoped to obtain polyfluorodibenz[b,f][l,4]oxazepinones from polyfluoro-2-hydroxybenzanilides. However, it turns out that o-hydroxy-N-(pentafluorobenzoyl)aniline (I) (obtained from pentafluorobenzoyl chloride and o-aminophenol) was unchanged when refluxed in DMF or heated at 100~ in DMF with anhydrous KF. When carried out in the presence of anhydrous potash the reaction led to an unidentified high melting product, insoluble in polar organic solvents. Cyclization of I succeeded when sodium hydride was used as the condensing agent. The low yield of 1,2,3,4-tetrafluorodibenz[b,f][l,4]oxazepin-ll-(10H)-one (IIa) and .the formation of a side product insoluble in DMF may, in this case, be due to a preferred intermolecular nucleophilic substitution reaction leading to oligomers.