A new nitro compound of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are each lower alkyl or lower alkoxy(lower)-alkyl, or ##STR2## is cyclized to form ##STR3## X is --O--, --S-- or --NH--, m is an integer 0 or 1, and R.sup.3 is carbamoyl, lower alkylcarbamoyl, lower alkanoyl, di-lower alkylaminosulfonyl, lower alkylsulfonyl, oxamoyl or a group of the formula: --(Y).sub.n --R.sup.4 wherein Y is --CO--, --SO.sub.2 --, --COCH.sub.2 -- or ##STR4## n is an integer of 0 or 1, and R.sup.4 is heterocyclic group which is optionally substituted with one or more substituents selected from lower alkyl, lower alkoxy, phenyl, carbamoyl, halogen, amino, lower alkylthio, hydroxy, lower alkylsulfonylamino and carbamoylmethyl, and pharmaceutically acceptable salt thereof, which are useful as vasodilators.