A compound of the formula
1
wherein R
1
is C
1-3
alkyl optionally substituted with one or more fluorines;
R
2
is CH
2
OCH
3
or 2 or 3-tetrahydrofuranyl;
R
3
is a pyrazole, imidazole or isoxazole group of partial formula (A), (B) or (C)
2
R
4
is C
1-3
alkyl; and
R
5
and R
6
, which may be the same or different, each represents C
1-3
alkyl, halogen, CF
3
or CN;
or a pharmaceutically-acceptable salt thereof.