New type of spin-labeled aminoenal

Ethynyl-substituted nitronyl nitroxide is involved in the 1,3-dipolar cycloaddition with cyclic nitrones without affecting the nitronyl nitroxide fragment. The reaction of 2,4,4,5,5-pentamethyl-4,5-dihydro-1H-imidazole 3-oxide produces the corresponding 1,2,3,7a-tetrahydroimidazo[1,2-b]isoxazole derivative. The analog of the latter derived from 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide is transformed into spin-labeled aminoenal. The solid phase of aminoenal is formed by packing unsymmetrical trimers resulting from the self-assembling of the molecular fragments based on a hydrogen bond network.