Abstract
Two approaches to the synthesis of polyazamacrocycles containing two biphenyl and two polyamine moieties are described. The first route comprises the synthesis of N,N'bis(bromobiphenyl) substituted diand poly-amines by the reactions of 2.2-3 equivalents of 4,4'or 3,3'-dibromobiphenyls with corresponding diand polyamines followed by the reaction with a second molecule of the amine. The second approach includes the synthesis of bis(polyamine) substituted biphenyls by the reactions of 4,4'or 3,3'-dibromobiphenyls with four equivalents of diand poly-amines with subsequent reaction of these in situ prepared intermediates with dibromobiphenyls. The yields of target macrocycles obtained according to two routes are compared and the advantage of the approach via bis(polyamine) substituted biphenyls in the majority of cases is established. Side products, when formed in all reactions, were analyzed.
Highlights
Macrocycles containing biphenyl units are of constant interest due to their interesting coordination possibilities which arise from the combination of flexible and tunable polyoxa- and polyaza-cycles with a rigid non-planar aryl moiety
The second approach via bis(polyamine)biphenyls provides better yields of some cyclodimers, and in this case the dependence of the result on the nature of starting compounds is pronounced: 4,4'-dibromobiphenyl gave 24% yield of the macrocycle with two trioxadiamine chains, whereas 3,3'-dibromobiphenyl afforded the cyclodimer with dioxadiamine in the highest yield (44%)
We suppose that two main factors govern the results of these two-step syntheses: the conformational factors of di- and polyamine chains at the macrocyclization step and the activity of the bromine atom in 4,4'- and 3,3'-dibromobiphenyls in competitive amination and reduction reactions at both steps of the processes
Summary
Macrocycles containing biphenyl units are of constant interest due to their interesting coordination possibilities which arise from the combination of flexible and tunable polyoxa- and polyaza-cycles with a rigid non-planar aryl moiety. N1,N1'-(Biphenyl-4,4'-diyl)bis(N3-(4'-bromobiphenyl-4-yl)propane-1,3-diamine) (4a) was obtained as the second product in the synthesis of compound 3a.
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