Repeated Diels–Alder reactions of the suitably curved and stiff reactants 1 and 2 furnish, via the central intermediate 3, the intellectually appealing title (and cover page) compound. In the last step of the synthesis, 3 is allowed to react with 2 under high pressure (9–10 kbar). The yield is nevertheless 20%. The Diels–Alder reactions are remarkably stereoselective, the intermediates are topologically extremely interesting, and the final product—it speaks for itself.
A benzene, an anthracene, and two naphthalene units, bound via 1,4‐cyclohexadiene synthetic groups, characterize the structure of the macropolycycle 1, which can be prepared by successive cleavage of O2 and H2O from a precursor. 1 may provide access to fascinating hydrocarbons like [12]cyclacene and [12]beltene.
A meso-p-nitroaniline-calix[4]pyrrole derivative trans-coordinated to a Pt(II) center was synthesized and its structure solved by X-ray analysis. Adenosine monophosphate (AMP) was used as a model compound to evaluate the potential for the assisted delivery of the metal to the DNA nucleobases via the phosphate anion-binding properties of the calix[4]pyrrole unit. An NMR investigation of the kinetics of AMP complexation in the absence of an H-bonding competing solvent (dry CD(3)CN) was consistent with this hypothesis, but we could not detect the interaction of the calix[4]pyrrole with phosphate in the presence of water. However, in vitro tests of the new trans-calixpyrrole-Pt(II) complex on different cancer cell lines indicate a cytotoxic activity that is unquestionably derived from the coexistence of both the trans-Pt(II) fragment and the calix[4]pyrrole unit.
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