Dibenzoxazepine

10-Alkyl-11-oxo-10,11-dihydro-dibenz-(b,f)(1,4)-azepine derivatives (I) are new. Dibenzoxazepinones of formula (I) and their salts, solvates and solvated salts are new. Y = 1-6C alkylidene, optionally (i) containing one or more double or triple bonds, (ii) substituted by one or more =O and/or (iii) having one or more C-atoms replaced by N, O or S, provided that any heteroatom in Y is not bonded directly to R3 or to another heteroatom in Y; R1, R4 = halo, CF3, OCF3, CN, NO2, NH2, alkylamino, OH, alkyl, alkoxy, COOH, alkoxycarbonyl, CONH2 or alkylaminocarbonyl; n = 0-3; m = 0-2; R2 = alkyl, optionally substituted by 1 or 2 of halo, OH, alkoxy, COOH, alkoxycarbonyl, CONH2, alkylaminocarbonyl or Q; Q = aryl, heteroaryl, cycloalkyl or heterocyclyl (all optionally substituted by 1-3 groups R1); R3 = OH or NH2. An Independent claim is included for the preparation of (I).