合成路线1

The macrocyclic tetraamine cyclam (I) is protected with p-toluenesulfonyl chloride at a 1:2 molar ratio, yielding the target tritosyl derivative (II) along with di- and monotosylated derivatives, which can be separated by fractional crystallization from MeOH (1). Subsequent condensation of (II) with α,α’-p-dibromoxylene (IIIa) gives the hexatosyl bis-cyclam (IV), which is finally deprotected by treatment with hot concentrated H2SO4 or with HBr in AcOH (1, 2). Alternatively, protection of (I) with di-tert-butyl dicarbonate provides the tri-Boc derivative (V), which is dimerized to (VI) by treatment with p-dibromoxylene (IIIa) and Na2CO3. Deprotection of (VI) is then effected by heating with aqueous HCl (3, 4). Similarly, treat-ment of the macrocyclic amine (I) with an excess of ethyl trifluoroacetate in the presence of Et 3N affords the tris-tri-fluoroacetyl cyclam (VII) as the major product. Subsequent condensation of (VII) with either p-dibro-moxylene (IIIa) or p-dichloroxylene (IIIb) in the presence of KI gives the trifluoroacetyl-protected compound (VIII), which is finally deprotected by treatment with NaOH or K2CO3 in MeOH (5, 6). Scheme 1.