The aerobic degradation of bupirimate has been studied in several studies. A total of six different soil types was used at different temperatures (15, 25 and 35 °C), with single and multiple application rates between 0.84 and 10 kg as/ha using formulated and non-formulated bupirimate. Under aerobic conditions, bupirimate degrades to ethirimol by cleavage of the sulphamate group, or to de-ethylated bupirimate (DE-B, 5-butyl-2- amino-6-methylpyrimidin-4-yl dimethyl sulphamate) by N-dealkylation of the 2-ethylamino moiety. DE-B and ethirimol further degrade to de-ethylated ethirimol (DE-E, 5-butyl-2-amino-6-methylpyrimidin-4-ol). An intermediate metabolite of ethirimol is tri-hydroxylated ethirimol.