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We herein report a modified, eco-friendly and atom-economical approach for the synthesis of a series of novel coumarin analogues via Suzuki–Miyaura cross-coupling methodology under mild conditions. The utilization of coumarin fluorosulfate as an atom-economical pseudohalide based electrophilic coupling partner was the key for success of our modified methodology. In addition, the use of water as a solvent, exceptionally milder reaction conditions and traditional catalytic systems further demonstrates the synthetic utility of the developed protocol. A comparative study of different pseudohalide leaving groups has been carried out in the later stage to understand the efficiency of aryl fluorosulfate. From this study, the increased hydrophilic nature of the fluorosulfate electrophilic coupling partner when compared to the other electrophiles has been realized. This allowed the increased solubility of the fluorosulfate electrophile in water under milder temperature conditions thereby furnishing the desired products in good to excellent yields.

Background and purpose: DNA damage can lead to carcinogenesis if replication proceeds without proper repair. This study focused on the purification of a novel quercetin derivative present in Terminalia chebula fruit and studied its protective role in hepatoma cells due to H2O2-DNA damage. Experimental approach: The pure compound obtained from the silica gel column was subjected to structural characterization using spectroscopic techniques. MTT assay was employed to select a non-toxic concentration of the isolated compounds on HepG2 and Chang liver cells. The antigenotoxic property of the compound on HepG2 and Chang liver cells was carried out by alkaline comet assay. Analyses of expression levels of mRNA for two DNA repair enzymes, OGG1 and NEIL1, in HepG2 and Chang liver cells, were carried out using the RT-PCR method. Findings/Results: The pure compound obtained from the fraction-5 of diethyl ether extract was identified as a novel quercetin derivative and named 7-(but-2-en-1-yloxy)-2-(4(but-2-en-1-yloxy)-3-hydroxyphenyl)-3- (hexa-2,4-dien-1-yloxy)-6-hydroxy-4H-chromen-4-one. This compound recorded modest toxicity at the highest concentration tested (percentage cell viability at 100 μg/mL was 64.71 ± 0.38 for HepG2 and 45.32 ± 0.07 for Chang liver cells). The compound has demonstrated noteworthy protection against H2O2-induced DNA damage in both cell lines. Analyses of mRNA expression levels for enzymes OGGI and NEIL1 enzymes in HepG2 and Chang liver cells asserted the protective role of the isolated compound against H2O2-induced DNA damage. Conclusion and implication: The protective effect of a novel quercetin derivative isolated from T. chebula in the hepatoma cells is reported here for the first time.

3,3'-(1,4-Phenylenebis(phenylazanediyl))bis(7-ethoxy-4-methyl-2H-chromen-2-one) was synthesized from N,N'-diphenylbenzene-1,4-diamine and bromo-7-ethoxy-4-methylcoumarin based on Ullmann coupling reaction. The synthesized compound was characterized by UV-Visible, NMR, FT-IR, MS, elemental analysis and Fluorescence Spectrum.