One‐Pot Synthesis of Highly Emissive Dipyridinium Dihydrohelicenes

Abstract

yesCondensation of a pyridyl-2-carbaldehyde derivative\ud with 2-(bromoethyl)amine hydrobromide gave tetracyclic\ud pyrido[1,2-a]pyrido[1’,2’:3,4]imidazo-[2,1-c]-6,7-dihydropyrazinium\ud dications in excellent yields. Crystal structures\ud and NOE data demonstrated the helical character of\ud the dications, the dihedral angles between the two pyrido\ud groups ranging from 28–458. An intermediate in the synthesis\ud was also characterized. A much brighter emission\ud compared to literature helicenes has been found, with\ud quantum yields as high as 60% in the range of l=460–\ud 600 nm. Preliminary cytotoxicity studies against HT-29\ud cancer cells demonstrated moderate-to-good activity, with\ud IC50 values 12–30x that of cisplatin.emailed RM Lord for final draft 28.09.2016 - sm\ud \ud © YYYY Wiley\ud This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

Synthesis, Optical Properties, and DNA Interaction of New Diquats Based on Triazolopyridines and Triazoloquinolines

“…In addition, compound 1 has shown relevance as an ion‐pair charge‐transfer complex and a supramolecular modulator . Similar structures have been reported in the literature by employing different alkylating agents or even more complex dinitrogen compounds . A number of related dicationic derivatives obtained by using different alkylating agents have also been reported.…”

“…[5] In ad-dition,c ompound 1 has shown relevancea sa ni on-pair charge-transfer complex [6] and as upramolecular modulator. [8][9][10][11] An umber of related dicationic derivatives obtainedb yu sing different alkylating agentsh avea lso been reported. [8][9][10][11] An umber of related dicationic derivatives obtainedb yu sing different alkylating agentsh avea lso been reported.…”

“…[8][9][10][11] An umber of related dicationic derivatives obtainedb yu sing different alkylating agentsh avea lso been reported. [8] Diquat is knownt oi nteract with DNA owing to its aromatic structure and dicationicc harge. The dihedral angle between the two pyridine rings depends on the lengthof the alkyl bridge.…”

“…[7] Similar structures have been reportedi nt he literature by employing different alkylatinga gentso re ven more complex dinitrogenc ompounds. [8][9][10][11] An umber of related dicationic derivatives obtainedb yu sing different alkylating agentsh avea lso been reported. Diquat derivatives possess axial chirality,w hich results in two enantiomeric configurations: P (R a )a nd M (S a ).…”

“…[12] Other derivatives without C 2 symmetry have also been described;for example, the dipyridiniumdihydrohelicenes described by Zysman-Colman in 2015, whicha dopt ahelicals tructure. [8] Diquat is knownt oi nteract with DNA owing to its aromatic structure and dicationicc harge. Althoughd iquat was reported to interact with DNA only through electrostatic interactions, [13] the incorporation of appropriate aromatic substituents can lead to intercalative binding modes.…”