Compounds of formula (I) and pharmaceutically acceptable salts thereof are disclosed: wherein A is optionally substituted phenyl, naphthyl, indolyl, quinolinyl, quinazolinyl, indazolyl, isoquinolinyl or benzofuranyl; b is 1, 2 or 3 and c is 1, 2 or 3, wherein b+c is 2, 3, 4 or 5; X is carbon, Y is CH, is a double bond and e is 0; or X is carbon, Y is CH2 or oxygen, is a single bond and e is 1; or X is nitrogen, Y is CH2, is a single bond and e is 0; R1 is hydrogen, cyano, halogen, C1-6alkyl, C1-6alkoxy, C1-6alkoxyC1-6alkyl, NHCOCH3 or OCONR5R6, wherein R5 and R6 are independently hydrogen or C1-6alkyl; R2 is halogen, cyano or C1-6alkoxy; d is 0, 1, 2 or 3; R3 is hydrogen, C1-6alkyl, C1-6alkanoyl, fluoroC1-6alkanoyl, C1-6alkylsulfonyl, fluoroC1-6alkylsulfonyl, carbamoyl, C1-6alkylcarbamoyl or arylC1-6alkyl; and R4, together with the nitrogen atom to which it is attached, forms an optionally substituted 5 to 7 membered heterocyclic group fused to the benzene ring, provided that when a compound of formula (I) has the following structure: wherein A, b, c, R1, e, X, Y, R2 and d are as defined above and R3 is hydrogen, C1-6alkyl or arylC1-6alkyl, then (i) X is carbon, Y is CH and is a double bond; or (ii) b and c are both 1; or (iii) the carbon atom adjacent to the oxo-substituted carbon atom in the morpholinyl ring, marked “*”, is substituted. Methods of preparing the compounds and uses of the compounds in therapy, in particular for a CNS disorder such as depression or anxiety, are also disclosed.