The invention provides compounds of formula (I)
wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, R
10
, R
11
and R
12
are as defined in the specification, and optical isomers, racemates and tautomers thereof, and pharmaceutically acceptable salts thereof; together with processes for their preparation, pharmaceutical compositions containing them and their use in therapy. The compounds are useful in the treatment of respiratory syncytial virus (RSV).