One‐Pot Synthesis of Highly Emissive Dipyridinium Dihydrohelicenes. Issue 19 (24th March 2015)

• Record Type: Journal Article
• Authors: Santoro, Amedeo; Lord, Rianne M.; Loughrey, Jonathan J.; McGowan, Patrick C.; Halcrow, Malcolm A.; Henwood, Adam F.; Thomson, Connor; Zysman‐Colman, Eli
• Is Part Of: Chemistry. Volume 21:Issue 19(2015)
• Page Start: 7035
• Page End: 7038
• Publication Date: 2015-03-24
• Subjects: crystal structures -- cytotoxicity -- fluorescence -- helical compounds -- voltammetry; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201406255
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Condensation of a pyridyl‐2‐carbaldehyde derivative with 2‐(bromoethyl)amine hydrobromide gave tetracyclic pyrido[1, 2‐ a ]pyrido[1′, 2′:3, 4]imidazo‐[2, 1‐ c ]‐6, 7‐dihydropyrazinium dications in excellent yields. Crystal structures and NOE data demonstrated the helical character of the dications, the dihedral angles between the two pyrido groups ranging from 28–45°. An intermediate in the synthesis was also characterized. A much brighter emission compared to literature helicenes has been found, with quantum yields as high as 60 % in the range of λ =460–600 nm. Preliminary cytotoxicity studies against HT‐29 cancer cells demonstrated moderate‐to‐good activity, with IC50 values 12–30× that of cisplatin. Abstract : Helical compounds : Condensation of a pyridyl‐2‐carbaldehyde derivative with 2‐(bromoethyl)amine hydrobromide gave tetracyclic pyrido[1, 2‐ a ]pyrido[1′, 2′:3, 4]imidazo‐[2, 1‐ c ]‐6, 7‐dihydropyrazinium dications in excellent yields. These afford unusually bright emissions for helicene‐like compounds, with Φ PL as high as 59.9 % in the range of λ =460–600 nm. Preliminary cytotoxicity studies against the HT‐29 cancer cell line demonstrated moderate‐to‐good activity, with inhibitor concentration (IC50 ) values 12–30× that of cisplatin (see scheme).