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The Eosin Y photocatalyzed Biginelli protocol has been established by a cascade one-pot three-component reaction of primary alcohols, α-ketoester, and urea to provide pharmacologically promising 3,4-dihydropyrimidin-2(1H)-ones in high yields. The key benefits of the present scheme are the capability to allow operational simplicity, readily available substrates, straightforward workup and high yields. This Eosin Y based photocatalytic approach can permit conquering traditional metal-catalyzed reactions in a sustainable manner, thus delivering economic and environmental rewards. An environmentally benign protocol for the synthesis of 3,4-DHPMs has been developed using inexpensive molecular oxygen, visible light as green energy source and eosin Y as photoreceptor-cum-sensitizer. The utilized photoreceptor revealed its unique properties in rapid intersystem crossing, high photo and chemical stability, ease of separation and high catalytic efficiency. [ABSTRACT FROM AUTHOR]

Perylene diimide (PDI) 3 and 4 appended with 8-hydroxyquinoline derivatives have been synthesized and their photophysical and spectroscopic properties have been experimentally determined. Moreover, PDIs 3 and 4 show ratiometric behavior to detect Cu colorimetrically with visible color change from coral red to light pink, whereas 3 and 4 show 'turn-off' behavior in fluorescence with lowest limit of detection 5 × 10 M. The PDI 3 could be further utilized for ratiometric CN detection colorimetrically and as 'turn-on' sensor for CN detection fluorometrically with lowest limit of detection 8 × 10 M. The comparison of spectroscopic properties of PDI 1-4 highlights the importance of linking 8-hydroxyquinoline units on the PDI core at bay position for achieving Cu recognition event into ratiometric signal. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]