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Synthesis of fluorescent tetracyclic lactams by a “one pot” three steps palladium-catalyzed borylation, Suzuki coupling (BSC) and lactamization: DNA and polynucleotides binding studies

Paper ID Volume ID Publish Year Pages File Format Full-Text
28143 44061 2007 8 PDF Available
Title
Synthesis of fluorescent tetracyclic lactams by a “one pot” three steps palladium-catalyzed borylation, Suzuki coupling (BSC) and lactamization: DNA and polynucleotides binding studies
Abstract

Tetracyclic lactams (benzothieno[2,3-c]quinolones) were prepared by “one pot” three steps palladium-catalyzed borylation, Suzuki coupling (BSC) and lactamization, starting from ortho-haloanilines and alkyl 3-bromobenzo[b]thiophene-2-carboxylates. The former were used as the components to be borylated with pinacolborane, and the latter as the brominated component in the Suzuki coupling. The amidation occurred with loss of the alkyl alcohol, presumably in the Suzuki coupling product, giving the corresponding tetracyclic lactam. This constitutes a novel application of the BSC reaction using sterically hindered substrates. In this work studies of absorption and fluorescence in several solvents and in presence of salmon sperm DNA or synthetic double-stranded (ds) heteropolynucleotides, poly(dA–dT)·(dA–dT) and poly(dG–dC)·(dG–dC), were performed. The binding constant values (Ki = 2.6 × 105 to 4.5 × 105 M−1) point to a high affinity of the lactams to DNA. It was shown that the intercalation is the preferred mode of binding and that the substituted new lactams (with F or OMe) exhibit a higher affinity for A–T regions.Quenching experiments with iodide show that the methoxylated lactam is the more intercalative in DNA. The same type of experiments using this compound bound to heteropolynucleotides show a very low accessibility (fa = 0.07) of the lactam in poly(dG–dC)·(dG–dC) to the quencher showing a large majority of intercalative binding while the high affinity for A–T regions together with a higher accessibility (fa = 0.25) point to the possibility of both intercalative (75%) and groove modes of binding.

Keywords
Palladium-catalyzed BSC reaction; Lactamization; Benzothieno[2,3-c]quinolones; Fluorescence; DNA and polynucleotides binding
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Synthesis of fluorescent tetracyclic lactams by a “one pot” three steps palladium-catalyzed borylation, Suzuki coupling (BSC) and lactamization: DNA and polynucleotides binding studies
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 190, Issue 1, 5 July 2007, Pages 45–52
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us