Abstract Thermally induced opening of the diaziridine ring in 6-aryl-2-methyl-1, 5- diazabicyclo [3.1. 0]-hexanes at the carbon-nitrogen bond is characterized by low regioselectivity; isomerization of unstable intermediate azomethine imines leads to mixtures of the corresponding 1-arylmethyl-5-methyl-4, 5-dihydro-1 H-pyrazoles and 1-arylmethyl-3- methyl-4, 5-dihydro-1 H-pyrazoles at a ratio of∼ 6: 5. Analogous regioselectivity in ...
