A compound represented by the formula: ##STR00001## [wherein R.sup.1 represents a hydrogen atom, a halogen, atom, alkyl group, etc., R.sup.2 represents a hydrogen atom, a halogen atom, alkyl group, etc., R.sup.3, R.sup.4, R.sup.5, R.sup.6 and R.sup.7 each independently represent a hydrogen atom, a halogen atom, a substitutable alkyl group, a substitutable alkenyl group, alkynyl group, a substituteable cycloalkyl group, etc., or R.sup.3, R.sup.4, R.sup.5, R.sup.6 and R.sup.7 may form a ring which may be substituted, which is formed by the adjacent two of them with carbon atoms to which the respective substituents are bonded, m and n each independently represent 0 or 1.] a salt thereof, an ester derivative thereof and an agricultural chemical containing the same as an effective ingredient, and a herbicidal composition containing the compound and a second herbicidally active compound as effective ingredients.