| 摘要 |
Compounds of the formula (I): <IMAGE> (I) or a pharmaceutically acceptable salt thereof wherein the NR1R2 moiety is a 5-, 6-, or 7-membered saturated heterocyclic ring; R3 is hydrogen, alkyl of 1 to 4 carbon atoms or acyl of 1 to 4 carbon atoms; R4 is naphthyl or phenyl unsubstituted or substituted by one or two substituents selected from the group consisting of fluorine, chlorine, bromine, methoxyl, benzyloxyl, trifluoromethyl, methyl, cyano, nitro, acetoxyl, amino, methylamino, ethylamino, dimethylamino, diethylamino, acetamide, hydroxyl, methoxycarbonyl, ethoxycarbonyl, carboxamido, sulphonamido, carboxy, trifluoromethylthio, trifluoromethoxyl, methylsulphonyl, trifluomethylsulphonyl and methylthio; R5 is hydrogen or alkyl of 1 to 4 carbon atoms; R6 is hydrogen or alkyl of 1 to 4 carbon atoms; X is oxygen and the dotted line represents a single or double bond. |
