| abstract |
The present invention provides improved processes for the synthesis of 1,4-ditosyl-1,4,7-triazacyclonone, comprising deprotecting a compound of formula (C): wherein P is tosylate or arylsulfonate, with an acidic medium to form 1,2-bis(1,4,7-triazacyclonon-1-yl)-ethane; and subsequently adding formaldehyde and formic acid to the acidic medium to form 1,2-bis-(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)-ethane (Me4-DTNE). The syntheses of intermediates are also disclosed. |