Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The selective synthesis of N-substituted derivatives of 1,4,8,11-tetraazacyclotetradecane may be achieved through N-tosyl or N-benzyl intermediates, permitting for example the synthesis of 1,8 disubstituted derivatives. ... Cookies are used by this site. To decline or learn more, ...