Novel nitrogen-containing heterocyclic compounds shown by the formula ##STR1## wherein one of R.sub.1 and R.sub.2 represents a lower alkyl group, a phenyl group, a halophenyl group, or a lower alkoxyphenyl group and the other of them represents a hydrogen atom, a lower alkyl group, or a phenyl lower alkyl group; said R.sub.1 and R.sub.2 may combine with each other to form a trimethylene group or a tetramethylene group; R.sub.3 represents a hydrogen atom, a lower alkyl group, a phenyl group, or a phenyl lower alkyl group; X represents an oxygen atom, a sulfur atom, an imino group, or a group shown by ##STR2## wherein m represents 1 or 2 and R.sub.4 represents a lower alkyl group, a hydroxy lower alkyl group, a cycloalkyl group or a phenyl lower alkyl group; and Y represents an ethylene group which may be substituted by lower alkyl group, a trimethylene group, a tetramethylene group, a vinylene group which may be substituted by a lower alkyl group, or ##STR3## wherein R.sub.5 represents a hydrogen atom, a lower alkyl group, a trifluoromethyl group, or a phenyl group; said X is the group shown by ##STR4## when one of said R.sub.1 and R.sub.2 is a lower alkyl group and the other is a hydrogen atom, and said Y is an ethylene group, 1/7and the pharmacologically acceptable non-toxic salts thereof.The compounds described above are strong analgesic anti-inflammatory agents.