Generation of oxynitrenes and confirmation of their triplet ground states.

New sulfoximine- and phenanthrene-based photochemical precursors to oxynitrenes have been developed. These precursors have been used to examine the chemistry and spectroscopy of oxynitrenes. The first EPR spectra of oxynitrenes are reported and are consistent with their triplet ground states.

Photochemistry of Phenyl-Substituted 1-Methylpyrazoles.

Direct irradiation of 1-methyl-4-phenylpyrazole (2) in methanol results in regiospecific phototransposition to 1-methyl-4-phenylimidazole (4) and in photocleavage to (E)/(Z)-3-(N-methylamino)-2-phenylpropenenitrile (5) and (E)/(Z)-2-(N-methylamino)-1-phenylethenyl isocyanide (6). Deuterium labeling confirms that the phototransposition occurs via the P(4) permutation pathway. Separate experiments show that 5 and 6 undergo (Z) --> (E) isomerization and photocyclization to imidazole 4.