Compounds of the formula (I), in which R
1
, R
2
, R
3
and R
4
have the meanings indicated in claim (
1
), are inhibitors of cell proliferation/cell vitality and can be employed for the treatment of tumours.
                            公式(I)的化合物,其中R1,R2,R3和R4具有权利要求(1)中指示的含义,是细胞增殖/细胞活力的
抑制剂,可用于肿瘤的治疗。