The preparation of 2-methoxy-4,5-dihydro-1H-imidazole (MeO-DHIM) was accomplished by one-step synthesis of O-methyl-isourea. The signal enhancement induced by these attached moieties increases in an order of compound 1 ≈ 4 < 2 < 5 ≈ 6 < 3 in MALDI mass spectrometry. Peptide-compound 3 adduct was approximately 20 times signal enhancement of the unmodified peptide.
Relation:
Journal of the Chinese Chemical Society 56(5), pp.987-994