| abstract |
A compound of the formula n nand physiologically acceptable salts and or N-oxides thereof wherein,n X 1 is N or CR 3 ; X 2 is N or CR 4 ; X 3 is N or CR 5 ; X 4 is N or CR 6 . with the proviso that at least one but not more than two of X 1 , X 2 , X 3 and X 4 represents N. R 1 is a 5-, or 6-membered heterocyclic group selected from group a, b, c or d n nwherein X 5 is a group selected from N or CR 7 and X 6 is a group selected from O, S or NR 8 ; X 7 and X 8 which may be the same or different is a group selected from N or CR 9 ; X 9 is a group selected from O, S or NR 8 and X 10 is N or CR 10 ; X 11 , X 12 and X 13 may be the same or different and selected from a group N or CR 11 ; processes for their preparation, pharmaceutical compositions containing them and their use in medicine. |