Fungicidally active compounds of the formula ##STR1## in which X represents oxygen or sulphur,R represents cycloalkyl, or represents optionally substituted aryl, or represents the radical ##STR2## R.sup.1 and R.sup.2 each independently is hydrogen or an organic radical, or together with the nitrogen atom form a heterocyclic radical,R.sup.3 represents hydrogen, alkyl or optionally substituted aryl, andR.sup.4 represents alkyl or cycloalkyl, or represents optionally substituted aryl,but wherein R.sup.3 and R.sup.4 may not simultaneously represent methyl,and acid addition salts thereof, as well as intermediates therefor.