Patent ID: 8633214

Claim:
A method for the treatment of insomnia and/or circadian rhythm sleep disorders in mammals, which comprises administering to the sufferer a therapeutically effective amount of a compound of formula (I): wherein R is hydrogen or C 1-4 alkyl; R 1 is hydrogen, C 1-4 alkyl, C(O)OH, C(O)NH 2 or (C 1-4 alkylene)R 10 ; R 2 and R 3 are independently hydrogen, C 1-4 alkyl or R 2 together with R 3 and together with the carbon atom to which they are attached form a C 3-8 cycloalkyl group; R 4 is C 1-4 alkyl, C 1-4 alkoxy or halogen; R 5 and R 7 are independently hydrogen, hydroxy, halogen, C(O)NH 2 , C(O)OH or (C 1-4 alkylene) R 10 ; R 6 and R 8 are independently hydrogen or halogen; R 9 is hydrogen, (C 1-4 alkylene)R 10 , C(O)NH 2 , C(O)OH or R 9 together with R form a 6 membered heterocyclic ring optionally containing a further heteroatom selected from oxygen, sulphur or nitrogen; R 10 is hydrogen, halogen, hydroxy, C(O)NH 2 , C(O)NH(C 1-4 alkyl), C(O)N(C 1-4 alkyl) 2 or C(O)OH; n is 0, 1 or 2: or a pharmaceutically acceptable salt thereof.