Synthesis, characterization, and photophysical properties of some new thieno[2,3‐<i>b</i>]pyridines bearing phenylethenyl moiety
Ahmed F. M. EL‐Mahdy, Etify A. Bakhite, Shams H. Abdel‐Hafez, Omaima F. Ibrahim, Hajjaj H.M. Abdu-Allah, Islam S. Marae
Abstract
Abstract 5‐Acetyl‐3‐cyano‐6‐methyl‐4‐(2‐phenylethenyl)pyridine‐2(1 H )‐thione ( 2 ) was synthesized by interaction of cinnamylidene‐2‐cyanothioacetamide 1 and acetylacetone or via one‐pot reaction of E ‐cinnamaldehyde, 2‐cyanothioacetamide, and acetylacetone. Reaction of 2 with ethyl iodide ( 3a ) or N ‐chloroacetyl derivative of aromatic amines 3b–e in boiling ethanol containing sodium ethoxide gave the corresponding thioether 4a and 5‐acetyl‐3‐amino‐2‐( N ‐arylcarbamoyl)‐6‐methyl‐4‐(2‐phenylethenyl)thieno[2,3‐ b ]pyridines 5b–e , respectively. Compound 5e was reacted with 2,5‐dimethoxytetrahydrofuran or triethyl orthoformate to furnish pyrrolylthienopyyridine 6 or pyrdiothienopyrimidinone 7 , respectively. The photophysical properties of 5b , 5c , 5e , and 7 were fully studied and the obtained results included herein. The fluorescence data confirmed that compounds 5b , 5c , 5e , and 7 exhibit aggregation‐induced emission behavior with high absolute quantum yields.