This invention relates to herbicidal active compounds and their use. The compounds of this invention correspond to the formula: ##STR1## wherein R is selected from cyclopropyl, ethyl, furyl, benzyl, methyl, and 3,4-methylenedioxybenzyl; R.sub.1 is selected from chloro and trifluoromethyl; R.sub.2 is selected from hydrogen, 4-chloro, 4-propargyloxy, and 5-chloro; R.sub.3 is selected from ethyl, chloroethyl, isobutyl, allyl and propargyl.