A REMARKABLE SELECTIVITY IN THE N-FUNCTIONALIZATION OF POLYAZA[N]PARACYCLOPHANES - SYNTHESIS OF N-(4-PICOLYL)-SUBSTITUTED 2,6,9,13-TETRAAZA[14]PARACYCLOPHANES

Interaction of cationic host species, in particular Zn2+ salts, with p olyaza[n]paracyclophanes (i.e. 2,6,9,13-Tetraaza[14]paracyclophane, B3 23 (1a)) directs their selective N-functionalization. In this way comp ounds mono-or difunctionalized with ArCH2-groups at the benzylic nitro gen atoms can be easily obtained. Direct reaction with the alkylating agent, in the absence of the Zn2+ species, produces, in general, very complex mixtures of mono-and polyalkylated compounds except when 4-pic olyl chloride is used. In this case, mono-, di-, tri- and tetra N-subs tituted derivatives of D323 can be isolated depending on the amount of the alkylating agent used. In this case, the mono- and dialkylated pr oducts obtained differ from the ones prepared using the metal assisted synthesis. (C) 1997 Elsevier Science Ltd.