Novel benzoxazinone derivatives useful for the treatment of cns disorders

A benzoxazinone derivative represented by Formula I

• a stereoisomer thereof or a mixture of its stereoisomers, or a pharmaceutically acceptable salt thereof, wherein
• at least one of R1, R2, R3 and R4, independently of each other, represents halo or cyano;
• and
• the other of R1, R2, R3 and R4, independently of each other, represent hydrogen, halo or cyano;
• R5 represents hydrogen or alkyl;
• R6 and R7, independently of each other, represent hydrogen or alkyl;
• and
• X represents an imidazole group, a 4,5-dihydro-1H-imidazole group, or the group —(CO)N(R6, R7), wherein R6 and R7, independently of each other, represent hydrogen or alkyl.