Compounds of the formula ##STR1## in which R.sup.1 is alkyl, cycloalkyl, aryl or hydrogen,R.sup.2 is --CO--R.sup.3,R.sup.3 is alkyl, alkenyl or cycloalkyl, or is phenyl which is optionally substituted, or is alkoxy or benzyl, or is phenoxy which is optionally substituted, or is phenoxymethyl, alkylamino, cycloalkylamino or phenylamino, orR.sup.1 and R.sup.2 together are a ##STR2## group, R.sup.4 and R.sup.5 each independently is hydrogen, alkyl, cycloalkenyl or phenylalkenyl, or is phenyl which is optionally substituted by alkyl, halogen and/or alkoxy, or is furyl, orR.sup.4 and R.sup.5 together are alkylene having 4 to 6 carbon atoms,are fungicidally active. Those compounds wherein R.sup.3 is alkylamino, cycloalkylamino or phenylamino, with the exception of the compound in which R.sup.1 is hydrogen and R.sup.6 is phenylamino, are new.