PREPARATION OF N-ARYLMETHYL AZIRIDINE DERIVATIVES, 1,4,7,10-TETRAAZACYCLODODECANE DERIVATIVES OBTAINED THEREFROM AND N-ARYLMETHYL-ETHANOL-AMINE SULPHONATE ESTERS AS INTERMEDIATES

摘要

Aziridines may be subjected to a cyclooligomerization reaction to produce polyazacycloalkane compounds useful for example in the preparation of chelating agents for use in diagnostic imaging contrast agents. N-benzyl-aziridine in particular is useful as it can be cyclotetramerized and debenzylated to yield cyclen, a key intermediate in chelating agent preparation. The invention provides a particularly attractive route to production of N-benzyl and other N-arylmethyl aziridines of formula (I), (where each R1 independently is hydrogen or a group Ar and Ar is an optionally substituted phenyl group), said process comprising reacting a purified N-arylmethylethanolamine-sulphonate ester with a base. N-arylmethyl-ethanolamine sulphonate ester of the formula: R'NHCH2CH2OSO3H, wherein the N-arylmethyl group R' is an N-(bisarylmethyl) or N-(triarylmethyl) group, as intermediates. In a further aspect the invention provides compounds of formula (II), where Ar and R1 are as hereinbefore defined and at least two differing ArCHR1 moieties are present.