A compound represented by the formula (I) (wherein R1, R2, R3 and R4 are as defined in the description), a tautomer, prodrug or pharmaceutically acceptable salt of the compound or a solvate thereof.
化合物的
化学式为(I),其中R1、R2、R3和R4如描述中所定义,化合物的互变异构体、前药或药理学上可接受的盐或其溶剂化物。