Intermediates for chelating agents with prefixed symmetry and process
申请人:Dibra S.p.A.
公开号:US05424423A1
公开(公告)日:1995-06-13
The preparation of compounds of formula (I), wherein R and R.sub.1 have the meanings specified in claim 1, is disclosed compounds (I) are useful intermediates for the preparation of chelating agents.
General methods for selective N-alkylations of the macrocycle 1,4,7,10-tetraazacyclododecane have been developed. The N-monoalkylation proceeds via a cyclic guanidinium derivative, and the regioselective 1,4-N,N-dialkylation via a cyclic amidinium derivative. All transformations were high yield reactions.
INTERMEDIATES FOR CHELATING AGENTS WITH PREFIXED SYMMETRY AND PROCESS FOR THEIR PREPARATION