A compound of the formula: ##STR1## wherein R.sup.1 is lower alkyl optionally substituted aryl; or amino optionally substituted; and R.sup.2 is hydrogen or lower alkyl; or R.sup.1 and R.sup.2 are taken together with the attached nitrogen atom to form a heterocyclic group optionally substituted; R.sup.3 is hydrogen or lower alkyl; and R.sup.4 is lower alkyl; and its pharmaceutically acceptable salt, processes for the preparation thereof and pharmaceutical composition comprising the same
一种化合物的公式:##STR1##其中R.sup.1是低碳基可选择取代芳基; 或
氨基可选择取代; R.sup.2是氢或低碳基; 或R.sup.1和R.sup.2与所连接的氮原子一起形成可选择取代的杂环基团; R.sup.3是氢或低碳基; R.sup.4是低碳基; 以及其药学上可接受的盐,其制备方法和包含该化合物的药物组成物。