Reactive intermediates. Part XIV. Photochemistry of phthalimidoaziridines and related systems

1-Phthalimidoaziridines (III) with a conjugating substituent, when irradiated in the presence of another olefin, undergo an exchange reaction which results in the formation of a new phthalimidoaziridine incorporating the added olefin. Evidence is presented to show that the reaction involves the concerted fragmentation of the phthalimidoaziridines to give olefins and phthalimidonitrene, which is then trapped by the added olefin. The reaction has been extended to 1-(3,4-dihydro-2-methyl-4-oxoquinazolin-3-yl)aziridines (V), but it is not a general reaction for all aziridines with a heteroatom substituent at the 1-position.