... J. Heterocyclic Chem., 43, 11 (2006 ... 5]. By selecting suitable substitutents at the ring nitrogen or car- bon atoms, aziridines can also be converted into less strained heterocycles, often in ... J = 3.2 Hz & 13.8 Hz, 1H, C3H), 3.69 (dd, J = 5.1 Hz & 13.8 Hz, 1H, C3H), 4.51 (dd, J = 3.2 Hz ...