A pharmaceutical compound of the formula ##STR1## in which R.sup.1 is halo-C.sub.1-10 alkyl, C.sub.1-10 alkylthio, halo-C.sub.1-10 alkylthio or optionally substituted phenylthio, R.sup.2 is hydrogen or C.sub.1-4 alkyl, R.sup.3 and R.sup.4 are each hydrogen or C.sub.1-4 alkyl, and X is oxygen or sulphur; and salts thereof.
一种药物化合物的
化学式为##STR1## 其中R.sup.1是卤代C.sub.1-10烷基,C.sub.1-10烷基
硫,卤代C.sub.1-10烷基
硫或可选取代苯基
硫,R.sup.2是氢或C.sub.1-4烷基,R.sup.3和R.sup.4分别是氢或C.sub.1-4烷基,X是氧或
硫;以及其盐。