A compound of the formula (I):
wherein
R
1
is hydrogen, halogen, carbamoyl, cyano, formyl, or lower alkyl optionally substituted with halogen, amino or a protected amino;
R
2
is hydrogen, halogen, cyano or lower alkoxy;
R
3
is phenyl or pyridyl, each of which is substituted with lower alkoxy; and
R
4
is lower alkoxy;
provided that either R
1
or R
2
is hydrogen, then the other is other than hydrogen, or its salts, which are useful as a medicament.
化合物的公式(I):其中R1是氢,卤素,
氨基甲酰基,
氰基,甲酰基或者低级烷基,该低级烷基可以选择性地被卤素,
氨基或者保护
氨基取代;R2是氢,卤素,
氰基或低级烷氧基;R3是苯基或
吡啶基,每个基都被低级烷氧基取代;R4是低级烷氧基;前提是,R1或R2中的一个是氢,则另一个不是氢。该化合物及其盐可用作药物。