1,3-Cycloaddition of benzonitrile oxides to diazepines.II. 1-Ethoxycarbonyl-4-methyl- and 6-methyl-1,2-diazepine

Article abstract of DOI:10.1016/S0040-4020(01)87975-8

Stable arylnitrile oxides (1b-e) and 1-ethoxycarbonyl-4-methyl and 6-methyl-1,2-diazepines (2f and 2h) undergo 1,3-cycloaddition reactions to give 1,2,4-oxadiazole derivatives (3) as the most abundant products. Secondary products of the class of isoxazoles (5 or 8) and 4,5-dihydroisoxazoles (6 or 7) were also identified. Overall kinetics were measured at 70.0°C, in mixtures of 1,1,2,2-tetrachloroethane and DMF; rate coefficients for the parallel reactions were obtained. Substituent and solvent effects are discussed.