(R)-(-)-Metalaxyl-d6

(R)-(−)-Metalaxyl-d₆ is intended for use as an internal standard for the quantification of (R)-(−)-metalaxyl by GC- or LC-MS. (R)-(−)-Metalaxyl is a fungicide and an active enantiomer of metalaxyl .^1,2 It is active against several isolates of the plant pathogenic fungus P. nicotianae (EC₅₀s = <0.01-2.9 µg/ml).¹ (R)-(−)-Metalaxyl (3 g/kg of seeds) completely protects sunflower plants (H. annus) from infection by P. helianthi.² It is toxic to D. magna and D. rerio (LC₅₀s = 176.4 and 237.67 mg/L, respectively).³ Formulations containing (R)-(−)-metalaxyl have been used in the control of fungi in agriculture.