Synthesis of 4-aryl-5,5-dimethyl-5 H-1,2,3-triazoles and 4-aryl-3-cyano-5,5-dimethyl Δ 1-pyrazolines by cycloaddition of 2-diazopropane with iminoethers and propenenitriles

Abstract

A regiospecific 1,3-dipolar cycloaddition of 2-diazopropane 3 to iminoethers 1a– c, carried out at 0 °C, afforded in two steps the corresponding 4-aryl-5,5-dimethyl-5 H-1,2,3-triazoles 5a– c. Under the same conditions, 3-arylpropenenitriles 2a– d led to 3-cyano-5,5-dimethyl Δ 1-pyrazolines 6a– d. Products 4– 6 were obtained in good yields (69–85%).