AZONIA-AZULENE SALTS .1 SYNTHESIS OF SOME 9-HYDROXYPYRROLO-=1,2-A'AZEPINIUM SALTS AND 10-HYDROXYAZEPINO=1,2-A.INDOLIUM SALTS

The syntheses of 1,2,3-tribromopyrrolo[1,2-a]azepin-9-one (23) and 11-methylazepino[1,2-a]indol-10-one (20), by a one-step elimination reaction from 1,2,3,8,8-pentabromo-6,7,8,9-tetrahydro-5H-pyrrolo[1,2-a]azepin-9-one (22) or 9,9-dibromo-7,8,9,10-tetrahydro-11-methyl-6H-azepino[1,2-a]indol-10-one (19) respectively, are described. The structures of the azepinones were established from their n.m.r. spectra and by hydrogenation of the pyrroloazepinone (23). Both azepinones on protonation gave hydroxyazonia-azulene salts; the pyrroloazepinone (23) with Meerwein's reagent gave 1,2,3-tribromo-9- ethoxypyrrolo[1,2-a]azepinium fluoroborate (25).