Preparation of a New Friedländer Synthon, 2,3‐Diaminobenzene‐1,4‐dicarbaldehyde, and Its Application towards Synthesis of 1,10‐Phenanthrolines and Related Cyclophane

Abstract

Friedländer reaction, 2,3-diaminobenzene-1,4-dicarbaldehyde, 1,3(2,9)-diphenanthrolina-2,4(2,6)-dipyridinacyclobutaphane, ligand design, synthetic methods *Summary of main observation and conclusion A new Friedländer synthon, 2,3-diaminobenzene-1,4-dicarbaldehyde, was prepared from p-xylene in 4 steps, of which the Friedländer reaction with acetaldehyde and acetone in a Schulenk bottle afforded 1,10-phenathroline and neocuprine in 44% and 82% yield, respectively. The scope of the Friedländer reactions of 2,3-diaminobenzene-1,4-dicarbaldehyde, including the synthesis of hexaazacyclic cyclophane with 1,10-phenanthroline and pyridine units, was described.. www.cjc.wiley-vch.de

Preorganization Effects on Eu(III) Ion Coordination by Dipyridyl-Phenanthroline Ligands: A Combined Experimental and Theoretical Analysis

“…All three ligands were obtained following known procedures . Ligand L1 was readily prepared by the Friedländer reaction of 2,3-diaminobenzene-1,4-dicarbaldehyde with double equimolar 2-acetylpyridine, which avoids the use of expensive Pd catalysts compared with previous Stile coupling reaction methods .…”

“…All three ligands were obtained following known procedures. 33 Ligand L1 was readily prepared by the Friedlander reaction of 2,3-diaminobenzene-1,4-dicarbaldehyde with double equimolar 2-acetylpyridine, which avoids the use of expensive Pd catalysts compared with previous Stile coupling reaction methods. 22 Two successive Friedlander condensations, 2,3-diaminobenzene-1,4-dicarbaldehyde with an equivalent of 6,7-dihydroquinolin-8(5H)-one and then with 2-acetylpyridine, were carried out to provide unsymmetrical ligand L2 (see Figure 2).…”

“…The ligands L1, L2, and L3 were synthesized according to known procedures with a mild modification (see Figure 2). 33 Their detailed synthesis processes and characterizations are described in SI.…”

Increasing the cytotoxicity of Ru(ii) polypyridyl complexes by tuning the electron-donating ability of 1,10-phenanthroline ligands

“…To that end, the deviant p -Amn-phen had much less steric hindrance to protecting from the solvent effect, which could be rotated by solvent interaction and resulted in irregular spectra. 44,45…”

“…To that end, the deviant p-Amn-phen had much less steric hindrance to protecting from the solvent effect, which could be rotated by solvent interaction and resulted in irregular spectra. 44,45 Biological properties Interaction with the amino acid L-histidine. As aforementioned, all of these Ru(II) complexes shared an important structural feature: each of them contained one labile Cl, which could be substituted in solutions or under physiological conditions as an active site to be essential for the antitumor activity.…”