Synthesis and Photophysical Properties of Polycarbo-Substituted Quinazolines Derived from the 2-Aryl-4-chloro-6-iodoquinazolines

• Main Authors: Malose Jack Mphahlele, Hugues Kamdem Paumo, Lydia Rhyman, Ponnadurai Ramasami
• Format: Article
• Language: English
• Published: MDPI AG 2015-08-01
• Series: Molecules
• Subjects: 2-aryl-4-chloro-8-iodoquinazolines; cross-coupling reactions; polycarbo-substituted quinazolines; photophysical properties
• Online Access: http://www.mdpi.com/1420-3049/20/8/14656

The reactivity of the 2-aryl-4-chloro-6-iodoquinazolines towards palladium catalyzed sequential (Sonogashira/Suzuki-Miyaura) and one-pot two-step cross-coupling (bis-Sonogashira, and successive Sonogashira/Stille) reactions to afford novel unsymmetrical polycarbo-substituted quinazolines has been evaluated. In contrast to the chloro-bromo substituted quinazolines in which selectivity has been previously found to generally favor substitution at the more activated C(4)-Cl bond over the weaker Csp2-Br bond, substitution in the case of the chloro-iodo derivatives favors cross-coupling through the intrinsically more reactive Csp2-I bond. The electronic absorption and emission properties of the prepared 2,3-diaryl-6-(phenylethynyl)quinazolines were studied in solvents of different polarity (dichloromethane, toluene, DMF, methanol) and CH2Cl2-TFA mixture using UV-Vis and emission spectroscopic techniques complemented with density functional theory method to establish the effect of substituents on intramolecular charge transfer properties.