COMPOUNDS USEFUL IN THERAPY

Compounds of formula (1), or a pharmaceutically acceptable derivative thereof,wherein R1 and R3 independently represent H, C1-6alkyl,C3-8cycloalkyl, or halogen; R2 represents C1-6alkyl,CF3 or aryl; a represents 1 or 2; R4, R5, R7and R8 independently represent H, C1-6alkyl,C1-6alkyloxy,CN or halogen, or R4 and R5, or R7 and R8,together with the ring to which they are attached form an aryl or heterocyclicfused ring system; X represents C or N; Y represents CH2 or O; R6represents H, CN or halo, but when X represents N then R6 representsH; may be useful for treating endometriosis, uterine fibroids (leiomyomata),menorrhagia, adenomyosis, primary and secondary dysmenorrhoea (includingsymptoms of dyspareunia, dyschexia and chronic pelvic pain), or chronic pelvicpain syndrome.