Fluorescent analogs of S-adenosyl-L-homocysteinase inhibitors derived from acyclic nucleoside series have been synthetized by alkylation of heterocyclic bases with appropriate synthons, or by modification of preformed adenine derivatives. None of the newly prepared compounds derived from 2-aminopurine, lin-benzoadenine or 1,6-ethenoadenine significantly inhibited the above enzyme.