Michael-type Addition as a Convenient Method for Regioselective N-Alkylation of Ambident Uracils

Boncel, Sławomir; Gondela, Andrzej; Walczak, Krzysztof

doi:10.1055/s-0029-1218757

Cited by 5 publications

(1 citation statement)

References 68 publications

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“…Nevertheless, decreased yields for azole adducts when DBU or NaH were used as catalysts at elevated temperature could originate from a reversibility of the Michael reaction since unreacted azoles were isolated. This observation is in a good agreement with our recent findings for Michael-type addition of uracils to acrylic acceptors [27,42], where a a strongly basic catalyst (DBU) enabled control of regioselectivity via a retro-Michael reaction.…”

Section: Resultssupporting

confidence: 92%

Michael-type addition of azoles of broad-scale acidity to methyl acrylate

Boncel¹,

Saletra²,

Hefczyc³

et al. 2011

Beilstein J. Org. Chem.

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SummaryAn optimisation of Michael-type addition of azole derivatives of broad-scale acidity – ranging from 5.20 to 15.00 pK a units – namely 4-nitropyrazole, 3,5-dimethyl-4-nitropyrazole, 4(5)-nitroimidazole, 4,5-diphenylimidazole, 4,5-dicyanoimidazole, 2-methyl-4(5)-nitroimidazole, 5(4)-bromo-2-methyl-4(5)-nitroimidazole and 3-nitro-1,2,4-triazole to methyl acrylate as an acceptor was carried out. The optimisation process involved the use of an appropriate basic catalyst (DBU, DIPEA, NaOH, NaH, TEDA), a donor/base/acceptor ratio and the reaction temperature. The reactions were performed in DMF as solvent. Target Michael adducts were obtained in medium to excellent yields. Importantly, for imidazole and 1,2,4-triazole derivatives, no corresponding regioisomers were obtained.

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Section: Resultssupporting

confidence: 92%

Michael-type addition of azoles of broad-scale acidity to methyl acrylate

Boncel¹,

Saletra²,

Hefczyc³

et al. 2011

Beilstein J. Org. Chem.

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Chemical Profiling of A‐to‐I RNA Editing Using a Click‐Compatible Phenylacrylamide

Knutson

Korn

Johnson

et al. 2020

Chemistry A European J

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Straightforwardm ethods for detecting adenosine-to-inosine (A-to-I) RNA editinga re key to ab etter understanding of its regulation, function, and connection with disease. Wea ddress this need by developing an ovel reagent, N-(4-ethynylphenyl)acrylamide (EPhAA), and illustrating its ability to selectively label inosine in RNA. EPhAA is synthesized in as ingle step, reacts rapidlyw ith inosine, and is "click"-compatible, enabling flexible attachment of fluorescent probesa te diting sites. We first validate EPhAA reactivity and selectivityf or inosine in both ribonucleosides and RNA substrates, and then apply our approach to directly monitor in vitro A-to-I RNA editing activity using recombinantA DAR enzymes. This method improves upon existing inosine chemical-labeling techniques and provides ac ost-effective, rapid, and non-radioactive approach for detecting inosine formation in RNA. We envision this method will improve the study of A-to-I editing and enable better characterization of RNA modification patterns in different settings. RNA is chemically modified by anumber of enzymes after transcription, in turn influencing RNA stability, localizationa nd activity within the cell. Adenosine-to-inosine (A-to-I) RNA editing is one of the most widespread modifications, and is performed by adenosine deaminases acting on RNA (ADARs) (Scheme 1a). [1] Adenosine deaminationc hanges the molecular structurea nd hydrogen-bonding pattern of the nucleobase, and resulting inosines insteadb ase pairw ith cytidinet oe ffectively recode these sites as guanosine. Editings ites within protein-coding mRNAsd irectly alter amino acid sequences and produce different protein isoforms. Non-coding RNAs also undergo extensive editing, including microRNAs and small-interfering RNAs, significantly alteringt heir biosynthesis, localization, and gene regulation properties. [2-3] A-to-I editing is essential for an umber of biological processes including tissue development, [4-5] neurologicalf unction, [6] and immune system activation. [7] Dysfunctional editing is also directlyl inked with autoimmune diseases, [8-9] neurological disorders, [10] and several types of cancer. [11-12] Despite this importance,o ur overall understanding of A-to-I editingr egulation is limited. In particular,w hile many sites have been identified (> 5million), [13-14] it is unclear why certain sites are edited at higherf requency than others and what precise function they each serve. [15] Efforts to map A-to-I locations and ADAR binding sites have revealed that editingp atterns are highly complex and variable in humans, [7, 16-18] and the precise mechanismsb yw hich ADAR enzymes bind to and edit specific RNA sequences remain unclear.T his gap is also significant for therapeutic site-directed RNA editing strategies, [19] as both the design and precise implementation of this machinery is reliant on at horough understanding of ADAR regulation. Detecting inosine formation in RNA is of central importance for characterizing editingm echanisms. While high-throughput RNA sequencin...

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