N-Nitrosoatrazine: Synthesis, Kinetics of Formation, and Nuclear Magnetic Resonance Spectra and Other Properties

N-Nitrosoatrazine (NNAT) was reported to be produced by the nitrosation of atrazine but was not fully characterized. We report here an improved synthesis of NNAT by nitrosation of atrazine in glacial acetic acid followed by high-performance liquid chromatography. the mass and infrared spectra confirmed that NNAT is a mononitroso derivative. the 1H and 13C nuclear magnetic resonance spectra of atrazine and NNAT were measured, including the use of selective decoupling, two-dimensional and homonuclear and heteronuclear correlation spectra, and variable-temperature experiments. These indicated that four syn–anti conformers of atrazine are present, attributed to restricted rotation of the two exocylic bonds (interconversion energy, 16.5 kcal/mol) and that NNAT contains the nitroso group attached to the N-ethyl nitrogen and exists as two conformers, attributed to restricted rotation about the exocylic bond to the N-isopropyl nitrogen (interconversion energy, 18.3 kcal/mol). NNAT was relatively stable in alkali and was photolabile. Nitrosation of atrazine in 1:1 ethanol-water followed third-order kinetics (first order for atrazine, HNO2, and H+), with a relatively low rate constant of 4.6 × 10−3 M−2 s−1 at 25 °C.