Synthesis and Fluorescence Properties of new Monastrol Analogs Conjugated Fluorescent Coumarin Scaffolds.

A mild and efficient method has been used for the synthesis of ethyl 4-(3-hydroxphenyl)-6-methyl-2-thioxo-1,3-dihydroprimidine-5-carboxylate (monastrol) (2), via Biginelli reaction. Alkylation of 2 with the fluorescent coumarin 3 afforded the new thioether analog 4. Similarly, ethyl 4-(6,8-dichloro-2-oxo-2 H-chromen-3-yl)-6-methyl-2-thioxo-1,2,3,4-tetrahydro-pyrimidine-5-carboxylate (6) was prepared. The synthesized compounds are fluorescent active and show wavelength of maximum absorption (λmax) in UV or visible region in MeOH at room temperature.