Total synthesis of C , N-imidacloprid with three stable isotopes in the pyridine ring.

Imidacloprid (IC) is an important crop-protecting insecticide worldwide and commonly used for seed treatment. However, only few data are available on human toxicity of IC. Having in view the metabolic studies at low doses in humans and residue analysis of IC in food and consumer products, we elaborated the synthesis and prepared C , N-IC with three stable isotopes of the "heavy" atoms in positions 1, 2, and 3 of the pyridine ring. By using readily available and affordable starting materials, NH Cl and C -acetic anhydride, the target compound has been prepared in eight steps with an overall yield of 13%.