A compound of the formula (I): ##STR00001## wherein R.sup.1 is a C.sub.1-C.sub.6 alkyl, an amino, a (C.sub.1-C.sub.6 alkyl)amino, a di(C.sub.1-C.sub.6 alkyl)amino or a nitrogen-containing saturated heterocyclic; R.sup.2 and R.sup.3 are the same or different and are a hydrogen or a C.sub.1-C.sub.6 alkyl; Arom is an unsubstituted or substituted aryl or an unsubstituted or substituted heteroaryl; wherein the substituted aryl is substituted at 1 to 5 positions and the substituted heteroaryl is substituted at 1 to 3 positions; wherein the heteroaryl is furyl, thiolyl, pyrrolyl, azepinyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, 1,2,3 oxadiazolyl, pyranyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl or quinolyl; and wherein the substituents of the substituted aryl and of the substituted heteroaryl are independently halogen, C.sub.1-C.sub.6 alkyl, halogeno C.sub.1-C.sub.6 alkyl, C.sub.1-C.sub.6 alkoxy, C.sub.1-C.sub.6 alkylthio, C.sub.1-C.sub.3 alkylenedioxy, C.sub.1-C.sub.7 alkanoyl, C.sub.2-C.sub.7 alkyloxycarbonyl, amino, C.sub.1-C.sub.7 alkanoylamino, hydroxyl, mercapto, cyano, nitro or carboxyl; A is an ethylene or propylene; R.sup.a is a hydrogen, a C.sub.1-C.sub.6 alkyl or a C.sub.2-C.sub.6 alkenyl; E is a single bond, an oxygen, a sulfur or --NR.sup.4--, wherein R.sup.4 is a hydrogen or a C.sub.1-C.sub.7 alkanoyl; X.sup.1 and X.sup.2 are the same or different and are an oxygen or a sulfur, or a pharmacologically acceptable salt or ester thereof.