A compound of the formula: ##STR1## wherein R.sub.1 is 3-pyridyl or 4-pyridyl; and R.sub.2 is hydrogen or lower alkyl (C.sub.1 -C.sub.3); or a nontoxic pharmaceutically acceptable salt thereof.
一种化合物的公式:##STR1##其中R.sub.1为3-
吡啶基或4-
吡啶基; R.sub.2为氢或较低的烷基(C.sub.1-C.sub.3);或其无毒药学上可接受的盐。