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Articoli di riviste sul tema "Alkylation"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 29 luglio 2024

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1

Saini, Natalie, Joan F. Sterling, Cynthia J. Sakofsky, Camille K. Giacobone, Leszek J. Klimczak, Adam B. Burkholder, Ewa P. Malc, Piotr A. Mieczkowski e Dmitry A. Gordenin. "Mutation signatures specific to DNA alkylating agents in yeast and cancers". Nucleic Acids Research 48, n. 7 (5 marzo 2020): 3692–707. http://dx.doi.org/10.1093/nar/gkaa150.

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Abstract Alkylation is one of the most ubiquitous forms of DNA lesions. However, the motif preferences and substrates for the activity of the major types of alkylating agents defined by their nucleophilic substitution reactions (SN1 and SN2) are still unclear. Utilizing yeast strains engineered for large-scale production of single-stranded DNA (ssDNA), we probed the substrate specificity, mutation spectra and signatures associated with DNA alkylating agents. We determined that SN1-type agents preferably mutagenize double-stranded DNA (dsDNA), and the mutation signature characteristic of the activity of SN1-type agents was conserved across yeast, mice and human cancers. Conversely, SN2-type agents preferably mutagenize ssDNA in yeast. Moreover, the spectra and signatures derived from yeast were detectable in lung cancers, head and neck cancers and tumors from patients exposed to SN2-type alkylating chemicals. The estimates of mutation loads associated with the SN2-type alkylation signature were higher in lung tumors from smokers than never-smokers, pointing toward the mutagenic activity of the SN2-type alkylating carcinogens in cigarettes. In summary, our analysis of mutations in yeast strains treated with alkylating agents, as well as in whole-exome and whole-genome-sequenced tumors identified signatures highly specific to alkylation mutagenesis and indicate the pervasive nature of alkylation-induced mutagenesis in cancers.

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2

Garcia-Ramos, Yesica, Caroline Proulx e William D. Lubell. "Synthesis of hydrazine and azapeptide derivatives by alkylation of carbazates and semicarbazones". Canadian Journal of Chemistry 90, n. 11 (novembre 2012): 985–93. http://dx.doi.org/10.1139/v2012-070.

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Hydrazine and azapeptide analogs were synthesized effectively by alkylation of alkylidene carbazates and semicarbazones. In comparisons of benzylidene, benzhydrylidene, and fluorenylidene tert-butyl carbazates in alkylations using bases of different pKb character, superior conversion was obtained using the fluorenone derivative. Mild alkylation conditions were found employing Et4NOH as base and used to convert fluorenylidene tert-butyl carbazate into 13 different protected hydrazines. Moreover, racemization was avoided during alkylation of fluorenylidene semicarbazide in the synthesis of aza-propargylglycinylphenylalanine tert-butyl ester, the protecting groups from which could be selectively removed.

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3

Hadzic, Pavle, Mirjana Popsavin e Suncica Borozan. "Alkylating ability of carbohydrate oxetanes: Practical synthesis of bolaform skeleton derivative". Journal of the Serbian Chemical Society 80, n. 10 (2015): 1273–78. http://dx.doi.org/10.2298/jsc150224033h.

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Alkylating ability of oxetane ring in carbohydrate structure was investigated and flexible method for bolaform amphiplile skeleton construction with xylose as polar heads is proposed. The method is based on oxetane ring opening in easily accessible 3,5-anhydro-1,2-O-cyclohexylidenexylofuranose (1). One step nitrogen alkylation in terminal diamines with 1 gave basic cationic bolaform skeleton with xylose as potential polar heads and deliberately chosen length of non polar spacer. Under similar experimental conditions, but with appropriate molar ratio of alkylating agent, alkylation reaction provide for selective monoalkylation of diamines. Successful alkylation in xanthine series (theophylline) was also achieved with 1, giving a new 5-deoxy-5-(7?-theophyllineamino)-?-D-xylofuranose derivative.

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4

McIntosh, John M., e Pratibha Mishra. "Alkylation of camphor imines of glycinates. Diastereoselectivity as a function of electronic factors in the alkylating agent". Canadian Journal of Chemistry 64, n. 4 (1 aprile 1986): 726–31. http://dx.doi.org/10.1139/v86-117.

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Alkylation of the (R)-camphor imine of tert-butyl glycinate with a variety of alkylating agents gave diastereoselectivities ranging from 0–100%. Simple alkyl halides larger than methyl give de's (diastereomeric excesses) of ca. 50% whereas those derived from allylic type systems afford de's of 75–100%. The results are best explained by invoking a transition state interaction between the π system of the alkylating agent and the imine which, for steric reasons, requires alkylation to occur from the pro-R face.

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5

Shimkin, Kirk W., e Donald A. Watson. "Recent developments in copper-catalyzed radical alkylations of electron-rich π-systems". Beilstein Journal of Organic Chemistry 11 (23 novembre 2015): 2278–88. http://dx.doi.org/10.3762/bjoc.11.248.

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Recently, a number of papers have emerged demonstrating copper-catalyzed alkylation reactions of electron-rich small molecules. The processes are generally thought to be related to long established atom-transfer radical reactions. However, unlike classical reactions, these new transformations lead to simple alkylation products. This short review will highlight recent advances in alkylations of nitronate anions, alkenes and alkynes, as well as discuss current mechanistic understanding of these novel reactions.

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6

Platzek, T., G. Bochert, U. Rahm e D. Neubert. "Embryotoxicity Induced by Alkylating Agents. Some Methodological Aspects of DNA Alkylation Studies in Murine Embryos Using Ethylmethanesulfonate". Zeitschrift für Naturforschung C 42, n. 5 (1 maggio 1987): 613–26. http://dx.doi.org/10.1515/znc-1987-0519.

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Abstract Synthesis and spectroscopic analysis of some alkylated DNA purine bases are described. HPLC separation methods are developed for the determination of DNA alkylation rates in mammalian embryonic tissues. Following treatment of pregnant mice with the ethylating agent ethyl-methanesulfonate (EMS), an appreciable amount of alkylation (ethylation and methylation) was found in the nuclear DNA of the embryos during organogenesis. The results are discussed in context of our thesis that a certain amount of DNA alkylation in the embryos is correlated to the teratogenic potential of alkylating agents.

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7

Goryunova, Alexandra Konstantinovna, Nina Sergeevna Baklan, Galina Vladimirovna Timofeeva e Elena Vladimirovna Nosova. "Studies of the Purolite CT151DRY alkylation catalyst by Purolite in the phenol alkylation reaction of ethylene oligomers of the C16-C18 fraction". Oil and gas technologies and environmental safety 2023, n. 3 (29 settembre 2023): 20–26. http://dx.doi.org/10.24143/1812-9498-2023-3-20-26.

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The possibility of using a Purolite alkylation catalyst of the CT151DRY brand in the reaction of alkylation of phenol with ethylene oligomers of the C16-C18 fraction to obtain the target alkylphenol, which is a semi-product in the production of multifunctional additives to lubricants is considered in the article. It is shown that the Purolite CT151DRY catalyst is resistant to mechanical influences and high temperatures within the studied range up to 180 °C and the synthesis duration up to 50 hours while maintaining a high alkylating ability in the reaction of phenol alkylation by ethylene oligomers of the C16-C18 fraction and is highly sensitive to changes in the composition of raw materials and the change of raw ethylene oligomers. The Purolite CT151DRY catalyst has an alkylating ability comparable to other catalysts and can be recommended to obtain the target alkylphenol.

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8

Kaliendina, S., M. Brynzei, M. Kut, S. M. Sukharev, Е. Ostapchuk e M. Onysko. "Kaliendina S., Brynzei M., Kut M., Sukharev S.M., Ostapchuk Е., Onysko M. REGIOSELECTIVITY OF ALKYLATION OF 2-(THIOPHENE-2-IL)THIENO[2,3 d]PYRIMIDINE-4(3H)-ONE". Scientific Bulletin of the Uzhhorod University. Series «Chemistry» 50, n. 2 (22 gennaio 2024): 40–45. http://dx.doi.org/10.24144/2414-0260.2023.2.40-45.

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Thieno[2,3-d]pyrimidines are an important class of heterocyclic compounds with a wide range of biological activities. The thieno[2,3-d]pyrimidin-4-one system is of the greatest interest to scientists, as it is one of a large number of possible thienopyrimidine derivatives. The presence of an amide fragment in these molecules allows for the introduction of various substituents via alkylation reactions. On the other hand, the presence of N- and O-nucleophilic centres makes it possible to form different types of alkylation products. In the present work, the alkylation reaction of 5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidin-4(3H)-one, which contains N(3)- and O-nucleophilic centres for attacking alkylating reagents, was investigated. Allyl bromide was used as an alkylating reagent. It was found that the alkylation of 5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidin-4(3H)-one with allyl bromide in DMF resulted in the regioselective preparation of 4-(allyloxy)-5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidine, which can be used in the future to study the process of electrophilic intramolecular cyclisation. An increase in the reaction time of the starting reagents leads to an increase in the yield of the target ester. Keywords: 5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidin-4(3H)-one; alkylation; regioselectivity; ether; 4-allyloxypyrimidine.

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9

Alagoz, Meryem, Owen S. Wells e Sherif F. El-Khamisy. "TDP1 deficiency sensitizes human cells to base damage via distinct topoisomerase I and PARP mechanisms with potential applications for cancer therapy". Nucleic Acids Research 42, n. 5 (12 dicembre 2013): 3089–103. http://dx.doi.org/10.1093/nar/gkt1260.

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Abstract Base damage and topoisomerase I (Top1)-linked DNA breaks are abundant forms of endogenous DNA breakage, contributing to hereditary ataxia and underlying the cytotoxicity of a wide range of anti-cancer agents. Despite their frequency, the overlapping mechanisms that repair these forms of DNA breakage are largely unknown. Here, we report that depletion of Tyrosyl DNA phosphodiesterase 1 (TDP1) sensitizes human cells to alkylation damage and the additional depletion of apurinic/apyrimidinic endonuclease I (APE1) confers hypersensitivity above that observed for TDP1 or APE1 depletion alone. Quantification of DNA breaks and clonogenic survival assays confirm a role for TDP1 in response to base damage, independently of APE1. The hypersensitivity to alkylation damage is partly restored by depletion of Top1, illustrating that alkylating agents can trigger cytotoxic Top1-breaks. Although inhibition of PARP activity does not sensitize TDP1-deficient cells to Top1 poisons, it confers increased sensitivity to alkylation damage, highlighting partially overlapping roles for PARP and TDP1 in response to genotoxic challenge. Finally, we demonstrate that cancer cells in which TDP1 is inherently deficient are hypersensitive to alkylation damage and that TDP1 depletion sensitizes glioblastoma-resistant cancer cells to the alkylating agent temozolomide.

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10

Yoshikai, Naohiko, e Ke Gao. "Cobalt-catalyzed directed alkylation of arenes with primary and secondary alkyl halides". Pure and Applied Chemistry 86, n. 3 (20 marzo 2014): 419–24. http://dx.doi.org/10.1515/pac-2014-5005.

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Abstract A cobalt–N-heterocyclic carbene catalyst allows ortho-alkylation of aromatic imines with unactivated primary and secondary alkyl chlorides and bromides under room-temperature conditions. The scope of the reaction encompasses or complements that of cobalt-catalyzed ortho-alkylation reactions with olefins as alkylating agents that we developed previously. Stereochemical outcomes of secondary alkylation reactions suggest that the reaction involves single-electron transfer from a cobalt species to the alkyl halide to generate the corresponding alkyl radical. A cycloalkylated product obtained by this method can be transformed into unique spirocycles through manipulation of the directing group and the cycloalkyl groups.

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11

Fahrer, Jörg, e Markus Christmann. "DNA Alkylation Damage by Nitrosamines and Relevant DNA Repair Pathways". International Journal of Molecular Sciences 24, n. 5 (28 febbraio 2023): 4684. http://dx.doi.org/10.3390/ijms24054684.

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Nitrosamines occur widespread in food, drinking water, cosmetics, as well as tobacco smoke and can arise endogenously. More recently, nitrosamines have been detected as impurities in various drugs. This is of particular concern as nitrosamines are alkylating agents that are genotoxic and carcinogenic. We first summarize the current knowledge on the different sources and chemical nature of alkylating agents with a focus on relevant nitrosamines. Subsequently, we present the major DNA alkylation adducts induced by nitrosamines upon their metabolic activation by CYP450 monooxygenases. We then describe the DNA repair pathways engaged by the various DNA alkylation adducts, which include base excision repair, direct damage reversal by MGMT and ALKBH, as well as nucleotide excision repair. Their roles in the protection against the genotoxic and carcinogenic effects of nitrosamines are highlighted. Finally, we address DNA translesion synthesis as a DNA damage tolerance mechanism relevant to DNA alkylation adducts.

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12

Qian, Bo, Hongli Bao, Yuehua Zeng e Yajun Li. "A Metal-Free Approach for Brønsted Acid Promoted C–H Alkylation of Heteroarenes with Alkyl Peroxides". Synthesis 50, n. 16 (29 maggio 2018): 3250–56. http://dx.doi.org/10.1055/s-0037-1609965.

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A metal-free protocol for Minisci C–H alkylation of heteroarenes using alkyl peroxides as the alkylating reagents and internal oxidants simultaneously under promotion of Brønsted acid has been demonstrated. A series of alkyl substituted heteroarenes were readily prepared by the C–H alkylation in moderate to good yields. A possible pathway involving the addition of alkyl radical to heterocycle followed by rearomatization is described.

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13

Memisoglu, Asli, e Leona Samson. "Contribution of Base Excision Repair, Nucleotide Excision Repair, and DNA Recombination to Alkylation Resistance of the Fission Yeast Schizosaccharomyces pombe". Journal of Bacteriology 182, n. 8 (15 aprile 2000): 2104–12. http://dx.doi.org/10.1128/jb.182.8.2104-2112.2000.

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ABSTRACT DNA damage is unavoidable, and organisms across the evolutionary spectrum possess DNA repair pathways that are critical for cell viability and genomic stability. To understand the role of base excision repair (BER) in protecting eukaryotic cells against alkylating agents, we generated Schizosaccharomyces pombe strains mutant for the mag1 3-methyladenine DNA glycosylase gene. We report that S. pombe mag1 mutants have only a slightly increased sensitivity to methylation damage, suggesting that Mag1-initiated BER plays a surprisingly minor role in alkylation resistance in this organism. We go on to show that other DNA repair pathways play a larger role than BER in alkylation resistance. Mutations in genes involved in nucleotide excision repair (rad13) and recombinational repair (rhp51) are much more alkylation sensitive thanmag1 mutants. In addition, S. pombe mutant for the flap endonuclease rad2 gene, whose precise function in DNA repair is unclear, were also more alkylation sensitive thanmag1 mutants. Further, mag1 andrad13 interact synergistically for alkylation resistance, and mag1 and rhp51 display a surprisingly complex genetic interaction. A model for the role of BER in the generation of alkylation-induced DNA strand breaks in S. pombe is discussed.

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14

Sakamoto, Ryu, Shunya Sakurai e Keiji Maruoka. "Bis(trialkylsilyl) peroxides as alkylating agents in the copper-catalyzed selective mono-N-alkylation of primary amides". Chemical Communications 53, n. 48 (2017): 6484–87. http://dx.doi.org/10.1039/c7cc02910a.

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15

Wei, Yahui, Qingqing Xuan, Yao Zhou e Qiuling Song. "Reductive N-alkylation of primary and secondary amines using carboxylic acids and borazane under mild conditions". Organic Chemistry Frontiers 5, n. 24 (2018): 3510–14. http://dx.doi.org/10.1039/c8qo00942b.

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16

Chen, Rongzhen, Jin-Tao Yu e Jiang Cheng. "Metal-free oxidative decarbonylative alkylation of chromones using aliphatic aldehydes". Organic & Biomolecular Chemistry 16, n. 19 (2018): 3568–71. http://dx.doi.org/10.1039/c8ob00720a.

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17

Li, Dengke, e Xianfu Shen. "Iron-catalyzed regioselective alkylation of 1,4-quinones and coumarins with functionalized alkyl bromides". Organic & Biomolecular Chemistry 18, n. 4 (2020): 750–54. http://dx.doi.org/10.1039/c9ob02289a.

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18

Stoltz, Brian, Samantha Shockley e J. Hethcox. "Intermolecular Stereoselective Iridium-Catalyzed Allylic Alkylation: An Evolutionary Account". Synlett 29, n. 19 (15 agosto 2018): 2481–92. http://dx.doi.org/10.1055/s-0037-1610217.

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Our lab has long been interested in the development of methods for the creation of enantioenriched all-carbon quaternary stereocenters. Historically, our interest has centered on palladium-catalyzed allylic alkylation, though recent efforts have moved to include the study of iridium catalysts. Whereas palladium catalysts enable the preparation of isolated stereocenters, the use of iridium catalysts allows for the direct construction of vicinal stereocenters via an enantio-, diastereo-, and regioselective allylic alkylation. This Account details the evolution of our research program from inception, which focused on the first iridium-catalyzed allylic alkylation to prepare stereodyads containing a single quaternary stereocenter, to our most recent discovery that allows for the synthesis of vicinal quaternary centers.1 Introduction2 Synthesis of Vicinal Tertiary and All-Carbon Quaternary Stereocenters via Enantio- and Diastereoselective Iridium-Catalyzed Allylic Alkylation2.1 Cyclic Nucleophiles2.2 Acyclic Nucleophiles2.3 Alkyl-Substituted Electrophiles3 Umpoled Iridium-Catalyzed Allylic Alkylation Reactions3.1 Tertiary Allylic Stereocenters3.2 Quaternary Allylic Stereocenters4 Synthesis of Vicinal All-Carbon Quaternary Centers via Enantioselective Iridium-Catalyzed Allylic Alkylation5 Summary and Future Outlook

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19

Sato, Norihiro, Genichiro Tsuji, Yoshihiro Sasaki, Akira Usami, Takuma Moki, Kazumitsu Onizuka, Ken Yamada e Fumi Nagatsugi. "A new strategy for site-specific alkylation of DNA using oligonucleotides containing an abasic site and alkylating probes". Chemical Communications 51, n. 80 (2015): 14885–88. http://dx.doi.org/10.1039/c5cc03915k.

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20

Bouziane, M., F. Miao, N. Ye, G. Holmquist, G. Chyzak e T. R. O'Connor. "Repair of DNA alkylation damage." Acta Biochimica Polonica 45, n. 1 (31 marzo 1998): 191–202. http://dx.doi.org/10.18388/abp.1998_4333.

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Alkylation damage of DNA is one of the major types of insults which cells must repair to remain viable. One way alkylation damaged ring nitrogens are repaired is via the Base Excision Repair (BER) pathway. Examination of mutants in both BER and Nucleotide Excision Repair show that there is actually an overlap of repair by these two pathways for the removal of cytotoxic lesions in Escherichia coli. The enzymes removing damaged bases in the first step in the BER pathway are DNA glycosylases. The coding sequences for a number of methylpurine-DNA glycosylases (MPG proteins) were cloned, and a comparison of the amino-acid sequences shows that there are some similarities between these proteins, but nonetheless, compared to other DNA glycosylases, MPG proteins are more divergent. MPG proteins have been purified to homogeneity and used to identify their substrates ranging from methylating agents to deamination products to oxidatively damaged bases. The ligation-mediated polymerase chain reaction has been used to study the formation of alkylation damage, and its repair in mammalian cells. We have studied DNA damage in the PGK1 gene for a series of DNA alkylating agents including N-methyl-N'-nitro-N-nitrosoguanidine, Mechlorethamine, and Chlorambucil and shown that the damage observed in the PGK1 (phosphoglycerate kinase 1) gene depends on the alkylating agent used. This report reviews the literature on the MPG proteins, DNA glycosylases removing 3-methyladenine, and the use of these enzymes to detect DNA damage at the nucleotide level.

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21

Schönbauer, David, Manuel Spettel, Robert Pollice, Ernst Pittenauer e Michael Schnürch. "Investigations of the generality of quaternary ammonium salts as alkylating agents in direct C–H alkylation reactions: solid alternatives for gaseous olefins". Organic & Biomolecular Chemistry 17, n. 16 (2019): 4024–30. http://dx.doi.org/10.1039/c9ob00243j.

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22

Mo, Fanyang, e Guangbin Dong. "Regioselective ketone α-alkylation with simple olefins via dual activation". Science 345, n. 6192 (3 luglio 2014): 68–72. http://dx.doi.org/10.1126/science.1254465.

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Alkylation of carbonyl compounds is a commonly used carbon-carbon bond–forming reaction. However, the conventional enolate alkylation approach remains problematic due to lack of regioselectivity, risk of overalkylation, and the need for strongly basic conditions and expensive alkyl halide reagents. Here, we describe development of a ketone-alkylation strategy using simple olefins as the alkylating agents. This strategy employs a bifunctional catalyst comprising a secondary amine and a low-valent rhodium complex capable of activating ketones and olefins simultaneously. Both cyclic and acyclic ketones can be mono-α-alkylated with simple terminal olefins, such as ethylene, propylene, 1-hexene, and styrene, selectively at the less hindered site; a large number of functional groups are tolerated. The pH/redox neutral and byproduct-free nature of this dual-activation approach shows promise for large-scale syntheses.

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23

Lambert, Georg, Ian C. Forster, Gerti Stange, Jürg Biber e Heini Murer. "Properties of the Mutant Ser-460-Cys Implicate This Site in a Functionally Important Region of the Type Iia Na+/Pi Cotransporter Protein". Journal of General Physiology 114, n. 5 (11 ottobre 1999): 637–52. http://dx.doi.org/10.1085/jgp.114.5.637.

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The substituted cysteine accessibility approach, combined with chemical modification using membrane-impermeant alkylating reagents, was used to identify functionally important structural elements of the rat type IIa Na+/Pi cotransporter protein. Single point mutants with different amino acids replaced by cysteines were made and the constructs expressed in Xenopus oocytes were tested for function by electrophysiology. Of the 15 mutants with substituted cysteines located at or near predicted membrane-spanning domains and associated linker regions, 6 displayed measurable transport function comparable to wild-type (WT) protein. Transport function of oocytes expressing WT protein was unchanged after exposure to the alkylating reagent 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA, 100 μM), which indicated that native cysteines were inaccessible. However, for one of the mutants (S460C) that showed kinetic properties comparable with the WT, alkylation led to a complete suppression of Pi transport. Alkylation in 100 mM Na+ by either cationic {[2-(trimethylammonium)ethyl] methanethiosulfonate bromide (MTSET), MTSEA} or anionic [sodium(2-sulfonatoethyl)methanethiosulfonate (MTSES)] reagents suppressed the Pi response equally well, whereas exposure to methanethiosulfonate (MTS) reagents in 0 mM Na+ resulted in protection from the MTS effect at depolarized potentials. This indicated that accessibility to site 460 was dependent on the conformational state of the empty carrier. The slippage current remained after alkylation. Moreover, after alkylation, phosphonoformic acid and saturating Pi suppressed the slippage current equally, which indicated that Pi binding could occur without cotransport. Pre–steady state relaxations were partially suppressed and their kinetics were significantly faster after alkylation; nevertheless, the remaining charge movement was Na+ dependent, consistent with an intact slippage pathway. Based on an alternating access model for type IIa Na+/Pi cotransport, these results suggest that site 460 is located in a region involved in conformational changes of the empty carrier.

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Hume, Paul A., Margaret A. Brimble e Jóhannes Reynisson. "The Bioreductive Alkylation of DNA by Kalafungin: A Theoretical Investigation". Australian Journal of Chemistry 65, n. 4 (2012): 402. http://dx.doi.org/10.1071/ch12018.

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The thermochemical cascades for the bioreductive alkylation of DNA by kalafungin were calculated using density functional theory (DFT). Guanine (G) was used as a model nucleotide. According to the calculations both one- and two-electron reduction of kalafungin is possible in vivo. Furthermore, a clear pathway was found for both mono- and bis-alkylations of G with the former favoured. Alkylation at C-8 position of G is considerably more exothermic than on the N2-exocyclic amine. In the absence of experimentally identified adduct structures of kalafungin, the results presented here support the idea that this compound readily forms covalent bonds with DNA resulting in pro-mutagenic lesions.

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Xu, Qing, Huamei Xie, Er-Lei Zhang, Xiantao Ma, Jianhui Chen, Xiao-Chun Yu e Huan Li. "Selective catalytic Hofmann N-alkylation of poor nucleophilic amines and amides with catalytic amounts of alkyl halides". Green Chemistry 18, n. 14 (2016): 3940–44. http://dx.doi.org/10.1039/c6gc00938g.

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A selective Hofmann N-alkylation reaction of amines/amides catalytic in alkyl halides is achieved by using alcohols as the alkylating reagents, affording mono- or di-alkylated amines/amides in high selectivities.

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26

Meng, Guangrong, Mehulkumar Patel, Feixiang Luo, Qingdong Li, Carol Flach, Richard Mendelsohn, Eric Garfunkel, Huixin He e Michal Szostak. "Graphene oxide catalyzed ketone α-alkylation with alkenes: enhancement of graphene oxide activity by hydrogen bonding". Chemical Communications 55, n. 37 (2019): 5379–82. http://dx.doi.org/10.1039/c9cc02578b.

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The first ketone-alkylation using olefins and alcohols as simple alkylating agents catalyzed by graphene oxide is reported. Extensive studies of the graphene surface suggest a pathway involving dual activation of both coupling partners.

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Ramadan, Sayed K., Wael S. I. Abou-Elmagd e Ahmed I. Hashem. "Alkylation of 2(3H)-Furanones: Inter- versus Intra-Molecular". Letters in Organic Chemistry 17, n. 6 (20 maggio 2020): 430–33. http://dx.doi.org/10.2174/1570178617666191203102528.

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In this review, a survey on the behavior of 2(3H)-furanones as alkylating agents is systematized. It is obvious that the direction of the reaction was mainly dependent on the solvent used. Furanones reacted with AlCl3 in excess benzene, toluene, or anisole to give the corresponding butadienecarboxylic acids via an intermolecular alkylation mode. Carrying out the reaction in tetrachloroethane and nitrobenzene as solvents, the reactions may lead to intramolecular alkylation mode or fail to give any product and the unreacted furanones were isolated, depending upon the electron density on C-2 at the aryl group situated at position-3.

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Begleiter, Asher. "The contribution of alkylation to the activity of quinone antitumor agents". Canadian Journal of Physiology and Pharmacology 64, n. 5 (1 maggio 1986): 581–85. http://dx.doi.org/10.1139/y86-096.

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Studies have shown that the quinone group can produce tumor cell kill by a mechanism involving active oxygen species. This cytotoxic activity can be correlated with the induction of DNA double strand breaks and is enhanced by the ability of the quinone compound to bind to DNA by alkylation. The cytotoxic activity and the production of DNA damage by model quinone antitumor agents were compared in L5178Y cells, sensitive and resistant to alkylating agents, to assess the contribution of alkylation to the activity of these agents. The resistant L5178Y/HN2 cells were found to be two fold and six fold more resistant to the alkylating quinones, benzoquinone mustard and benzoquinone dimustard, respectively, than parent L5178Y cells. In contrast, the L5178 Y/HN2 cells showed no resistance to the nonalkylating quinones, hydrolyzed benzoquinone mustard and bis(dimethylamino)benzoquinone. The alkylating quinones produced approximately two fold less cross-linking in L5178Y/HN2 cells compared with L5178Y sensitive cells. DNA double strand break formation by hydrolyzed benzoquinone mustard and bis(dimethylamino)benzoquinone was not significantly different in sensitive and resistant cells. However, the induction of double strand breaks by the alkylating quinones benzoquinone mustard and benzoquinone dimustard was reduced by 5-fold and 15-fold, respectively, in L5178Y/HN2 cells. These results show that the alkylating activity of the alkylating quinones cannot directly explain all of the enhanced cytotoxic activity of these agents. Furthermore, they provide strong evidence that the enhanced formation of DNA double strand breaks by alkylating quinone agents is directly related to the ability of these agents to bind to DNA. This increased formation of strand breaks may account for the enhanced cytotoxic activity of the alkylating quinones.

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29

Rana, Jagannath, Virendrakumar Gupta e Ekambaram Balaraman. "Manganese-catalyzed direct C–C coupling of α-C–H bonds of amides and esters with alcohols via hydrogen autotransfer". Dalton Transactions 48, n. 21 (2019): 7094–99. http://dx.doi.org/10.1039/c8dt05020a.

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Abstract (sommario):

Mn-catalyzed C-alkylation of amides and tert-butyl acetate using alcohols as alkylating agents is reported. This approach exhibits a broad substrate scope providing the C(α)-alkylated amides in good yields via hydrogen auto-transfer strategy.

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30

Khatri, Praveen K., Manvi Manchanda, Indrajit K. Ghosh e Suman L. Jain. "Polymer impregnated sulfonated carbon composite solid acid catalyst for alkylation of phenol with methyl-tert-butyl ether". RSC Advances 5, n. 5 (2015): 3286–90. http://dx.doi.org/10.1039/c4ra11033a.

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Abstract (sommario):

A polymer impregnated sulfonated carbon composite solid acid catalyst was synthesized via sulfonation of a composite material and used for the alkylation of phenol using methyl-tert-butyl ether as an alkylating agent in a pressure reactor under autogenous pressure.

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31

Zhang, Qiao Y., Xin J. Cheng, Xin Y. Zhao, La M. Wu, Long F. Jin e Hui J. Zhang. "Combined Alkylating Agents as a Resolution for Highly Selective N-Alkylation of 2-Hydroxybenzaldehyde Acylhydrazones". Synlett 30, n. 11 (8 maggio 2019): 1334–38. http://dx.doi.org/10.1055/s-0037-1611823.

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Abstract (sommario):

Although 2-hydroxybenzaldehyde acylhydrazones, such as salicylaldehyde acylhydrazones, are intriguing bioactive molecules, few of their N-alkylated derivatives are known, and only methyl analogues have been reported previously. We achieved selective N-alkylation of 2-hydroxybenzaldehyde acylhydrazones, as their Fe(III) complexes, by using combinations of alkylating agents (for example, an alkyl bromide and a dialkyl sulfate). Fifteen substrates were examined, and 45 new 2-hydroxybenzaldehyde acyl(alkyl)hydrazones were synthesized in moderate to good yields. In all cases, the target products were obtained exclusively, and no O-alkylation byproducts were produced. The method provides an efficient way of preparing 2-hydroxybenzaldehyde acyl(alkyl)hydrazones.

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32

Samruddhi, Mane, Akash Bhatkar, Marimuthu Prabu, Siva Prasad Mekala, Pranjal Gogoi, Gourab Mohapatra e Raja Thirumalaiswamy. "Selective O-alkylation of Phenol Using Dimethyl Ether". Reactions 3, n. 4 (17 novembre 2022): 602–14. http://dx.doi.org/10.3390/reactions3040040.

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Abstract (sommario):

Anisole is a straw-colored aromatic compound mainly used in making solvents, flavoring agents, perfumes, fuel additives, and in the synthesis industries. Anisole, also known as methoxybenzene, is synthesized from sodium phenoxide or phenol using various methylating agents. The use of dimethyl ether (DME) as an alkylating agent is seldom reported in the literature. Herein, we have synthesized anisole through the O-alkylation process of phenol and DME to obtain zero discharge from this process. The thermodynamic equilibrium for the reaction of phenol and DME is simulated by using Aspen HYSYS (Hyprotech and Systems). The O-alkylation of phenol has been investigated using phosphotungstic acid (PTA) over γ-Al2O3 with appropriate acidity. Active metal loadings of various percentages were studied and the conversion was optimized at 46.57% with a selectivity of 88.22% at a temperature of 280 °C. The liquid products from the continuously stirred reactor were analyzed with liquid G.C. and the conversion and selectivity were calculated. A comparison of the O-alkylation and C-alkylation of phenol at different temperatures, reactant ratios, residence times, and recyclability was explored, as well as the impact of these factors on the yield of the desired anisole. The catalyst was characterized by XRD, BET, HR-TEM, FE-SEM, elemental mapping, XPS, and DRIFT studies.

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33

Liu, Chang, Jianwei Sun e Pengfei Li. "Chiral Phosphine Catalyzed Allylic Alkylation of Benzylidene Succinimides with Morita–Baylis–Hillman Carbonates". Molecules 28, n. 6 (21 marzo 2023): 2825. http://dx.doi.org/10.3390/molecules28062825.

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Abstract (sommario):

Owing to their unique chemical properties, α-alkylidene succinimides generally act as versatile synthons in organic synthesis. Compared with well-established annulations, nucleophilic alkylations of α-alkylidene succinimides are very limited. Accordingly, an organocatalytic allylic alkylation of α-benzylidene succinimides with Morita–Baylis–Hillman (MBH) carbonates was established. In the presence of a chiral phosphine catalyst, α-benzylidene succinimides reacted smoothly with MBH carbonates under mild conditions to furnish a series of optical active succinimides in high yields and enantioselectivities. Different from the reported results, the organocatalytic enantioselective construction of pyrrolidine-2,5-dione frameworks bearing contiguous chiral tertiary carbon centers was achieved via this synthetic strategy. Scaling up the reaction indicated that it is a practical strategy for the organocatalytic enantioselective alkylation of α-alkylidene succinimides. A possible reaction mechanism was also proposed.

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34

Keglevich, György, Nóra Kiss, Alajos Grün, Erika Bálint e Tamara Kovács. "Advantages of the Microwave Tool in Organophosphorus Syntheses". Synthesis 49, n. 14 (20 giugno 2017): 3069–83. http://dx.doi.org/10.1055/s-0036-1589031.

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Abstract (sommario):

The microwave (MW) technique has become an important tool also in the organophosphorus field of organic chemistry. On the one hand, otherwise reluctant reactions, such as the esterification of P-acids, may be enhanced by the effect of MW, while on the other hand, catalysts may be omitted, or catalyst systems may be simplified on MW irradiation. This later group includes the Kabachnik–Fields reactions, alkylation of active methylene-containing compounds, O-alkylations, deoxygenations, as well as the Hirao reaction. It is also the purpose of this review to elucidate the scope and limitations of the MW tool, to interpret the MW effects, and to model the distribution of local overheatings and their beneficial effect.1 Introduction2 The Esterification of Phosphinic Acids2.1 Synthetic Results2.2 Scope and Limitation of the Application of MWs2.3 Modelling the Distribution of the Local Overheatings and Predicting Their Effect3 The Simplification of Catalytic Systems3.1 Replacement of the Catalyst by MW Irradiation3.1.1 The Kabachnik–Fields Reaction3.1.2 Solid–Liquid Phase Alkylation of Active Methylene-Containing Compounds3.1.3 Solid–Liquid Phase Alkylation of Phosphinic Acids3.1.4 The Deoxygenation of Phosphine Oxides3.2 The Hirao Reaction without Added P-Ligands4 Conclusions

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35

Xu, Di, Lena Frank, Tina Nguyen, Andreas Stumpf, David Russell, Remy Angelaud e Francis Gosselin. "Magnesium-Catalyzed N2-Regioselective Alkylation of 3-Substituted Pyrazoles". Synlett 31, n. 06 (9 agosto 2019): 595–99. http://dx.doi.org/10.1055/s-0039-1690160.

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Abstract (sommario):

A highly regioselective Mg-catalyzed alkylation of 3-substituted pyrazoles has been developed to provide N2-alkylated regioisomers. Using α-bromoacetates and acetamides as alkylating agents, this new method was applied to a variety of 3-substituted and 3,4-disubstituted pyrazoles to produce the N2-alkylated products with high regioselectivities ranging from 76:24 to 99:1 and 44–90% yields.

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36

Mijin, Dusan, Milica Misic-Vukovic e Slobodan Petrovic. "Alkylation of N-substituted-2-phenylacetamides". Journal of the Serbian Chemical Society 69, n. 10 (2004): 711–36. http://dx.doi.org/10.2298/jsc0410711m.

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Abstract (sommario):

Various N-substituted phenylacetamides were alkylated using different alkylating agents under neutral and basic conditions. Reactions were performed at different reaction temperatures and in various solvents. Also, a number of various catalysts were used including phase-transfer catalysts. Reactions were followed using GC or GC-MS technique and the presence as well as the yields of the alkylation products were established. Generally, the best yield and high selectivity in the studied reactions were achieved under basic conditions where in the certain cases some products, mostly N-product were obtained solely in quantitative yields.

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37

Gogoi, Dipanta, Lalmalsawm tluangi e Zodinpuia Pachuau. "Theoretical Study on the Mechanism of Alkylation At 0-6 Position of Guanine by Temozolomide and Bitc-Temozolomide". Science & Technology Journal 6, n. 2 (1 luglio 2018): 68–74. http://dx.doi.org/10.22232/stj.2018.06.02.12.

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Abstract (sommario):

Temozolomide, an alkylating prodrug mainly used in the treatment of malignant glioblastoma(brain cancer). However, after giving dose of TMZ, there is a chance of reappearance of cancer cell after few days. The purpose of this study is to shade more light on mechanism of alkylation at O-6 position of guanine by TMZ and BITC-TMZ through computationally. This study will lead to gain of useful information of drug design and development. Along with the geometrical optimization using density functional theory, MEP and FMO parameters are also calculated. As the alkylation takes place at the O-6 of guanine of DNA. Therefore, this study mainly focus on the guanine sructures. The physiological properties of BITC-TMZ is found to be similar with the TMZ.

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38

Onizuka, Kazumitsu, Madoka E. Hazemi, Norihiro Sato, Gen-ichiro Tsuji, Shunya Ishikawa, Mamiko Ozawa, Kousuke Tanno, Ken Yamada e Fumi Nagatsugi. "Reactive OFF-ON type alkylating agents for higher-ordered structures of nucleic acids". Nucleic Acids Research 47, n. 13 (12 giugno 2019): 6578–89. http://dx.doi.org/10.1093/nar/gkz512.

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Abstract (sommario):

Abstract Higher-ordered structure motifs of nucleic acids, such as the G-quadruplex (G-4), mismatched and bulge structures, are significant research targets because these structures are involved in genetic control and diseases. Selective alkylation of these higher-order structures is challenging due to the chemical instability of the alkylating agent and side-reactions with the single- or double-strand DNA and RNA. We now report the reactive OFF-ON type alkylating agents, vinyl-quinazolinone (VQ) precursors with a sulfoxide, thiophenyl or thiomethyl group for the OFF-ON control of the vinyl reactivity. The stable VQ precursors conjugated with aminoacridine, which bind to the G-4 DNA, selectively reacted with a T base on the G-4 DNA in contrast to the single- and double-strand DNA. Additionally, the VQ precursor reacted with the T or U base in the AP-site, G-4 RNA and T-T mismatch structures. These VQ precursors would be a new candidate for the T or U specific alkylation in the higher-ordered structures of nucleic acids.

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39

Khlebnikova, Elena, Irena Dolganova, Elena Ivashkina e Stanislav Koshkin. "Modeling of Benzene with Ethylene Alkylation". International Journal of Chemical Engineering and Applications 8, n. 1 (febbraio 2017): 61–66. http://dx.doi.org/10.18178/ijcea.2017.8.1.631.

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40

Yudovin-Farber, Ira, Jacob Golenser, Nurit Beyth, Ervin I. Weiss e Abraham J. Domb. "Quaternary Ammonium Polyethyleneimine: Antibacterial Activity". Journal of Nanomaterials 2010 (2010): 1–11. http://dx.doi.org/10.1155/2010/826343.

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Abstract (sommario):

Quaternary ammonium polyethyleneimine- (QA-PEI-) based nanoparticles were synthesized using two synthetic methods, reductive amination and N-alkylation. According to the first method, QA-PEI nanoparticles were synthesized by cross-linking with glutaraldehyde followed by reductive amination with octanal and further N-methylation with methyl iodide. The second method is based on crosslinking with dialkyl halide followed by N-alkylation with octyl halide and further N-methylation with methyl iodide. QA-PEI nanoparticles completely inhibited bacterial growth (>106bacteria), including both Gram-positive, that is,Staphylococcus aureusat 80 g/mL, and Gram-negative, that is,Escherichia coliat 320 g/mL. Activity analysis revealed that the degree of alkylation and N-methylation of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl alkylated QA-PEI alkylated at 1 : 1 mole ratio (primary amine of PEI monomer units/alkylating agent). Also, cytotoxicity studies on MAT-LyLu and MBT cell lines were performed with QA-PEI nanoparticles. These findings confirm previous reports that polycations bearing quaternary ammonium moieties inhibit bacterial growthin vitroand have a potential use as additives in medical devices which need antibacterial properties.

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41

Morales-Ríos, Martha S., Ernesto Rivera-Becerril, Daphne E. González-Juárez, Juan Benjamín García-Vázquez, Joel J. Trujillo-Serrato, Angelina Hernández-Barragán e Pedro Joseph-Nathan. "Synthesis of Pyrrolidinoindolines from 2-(2-Oxo-3-indolyl)acetates: Scope and Limitations". Natural Product Communications 6, n. 4 (aprile 2011): 1934578X1100600. http://dx.doi.org/10.1177/1934578x1100600406.

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Abstract (sommario):

A series of 1,3a,8-alkylpyrrolidinoindolines have been synthesized. The scope and limitations of the alkylation of starting methyl oxindol-3-acetates are explored employing electron-rich and electron-poor alkylating agents. Hydrolysis and reductive lactonization of the resulting carboxylic γ-oxindolic acid derivatives proceeds with good yields to afford 2-oxofuroindolines providing ready access to the pyrrolidinoindoline derivatives.

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42

Zhao, Zhensheng, Islam Jameel e Graham K. Murphy. "Vicinal Dichlorination of o-Vinylbiphenyls and the Synthesis of 9-(Arylmethyl)fluorenes via Tandem Friedel–Crafts Alkylations". Synthesis 51, n. 13 (28 maggio 2019): 2648–59. http://dx.doi.org/10.1055/s-0037-1611562.

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Abstract (sommario):

Reacting ortho-vinylbiphenyls with (dichloroiodo)benzene (PhICl2) gives vicinal dichlorides, rapidly, and in excellent yield at room temperature. Treating the vic-dichlorides with 50 mol% AlCl3 in the presence of arene nucleophiles results in sequential intramolecular and intermolecular Friedel–Crafts alkylations to generate 9-(arylmethyl)fluorene derivatives. The dichlorination and alkylation reactions are operationally simple and tolerant of a variety of functional groups and substitution patterns, and give the products in moderate to excellent yield.

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43

Liu, Tinglan, Yu Zhou, Junhong Tang e Chengming Wang. "Recent advancements in iodide/phosphine-mediated photoredox radical reactions". Beilstein Journal of Organic Chemistry 19 (22 novembre 2023): 1785–803. http://dx.doi.org/10.3762/bjoc.19.131.

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Abstract (sommario):

Photoredox catalysis plays a crucial role in contemporary synthetic organic chemistry. Since the groundbreaking work of Shang and Fu on photocatalytic decarboxylative alkylations in 2019, a wide range of organic transformations, such as alkylation, alkenylation, cyclization, amination, iodination, and monofluoromethylation, have been progressively achieved using a combination of iodide and PPh3. In this review, we primarily focus on summarizing the recent advancements in inexpensive and readily available iodide/phosphine-mediated photoredox radical transformations.

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44

Araujo-Lima, Carlos F., Larissa S. A. Christoni, Graça Justo, Maria N. C. Soeiro, Claudia A. F. Aiub e Israel Felzenszwalb. "Atorvastatin Downregulates In Vitro Methyl Methanesulfonate and Cyclophosphamide Alkylation-Mediated Cellular and DNA Injuries". Oxidative Medicine and Cellular Longevity 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/7820890.

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Abstract (sommario):

Statins are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, and this class of drugs has been studied as protective agents against DNA damages. Alkylating agents (AAs) are able to induce alkylation in macromolecules, causing DNA damage, as DNA methylation. Our objective was to evaluate atorvastatin (AVA) antimutagenic, cytoprotective, and antigenotoxic potentials against DNA lesions caused by AA. AVA chemopreventive ability was evaluated using antimutagenicity assays (Salmonella/microsome assay), cytotoxicity, cell cycle, and genotoxicity assays in HepG2 cells. The cells were cotreated with AVA and the AA methyl methanesulfonate (MMS) or cyclophosphamide (CPA). Our datum showed that AVA reduces the alkylation-mediated DNA damage in different in vitro experimental models. Cytoprotection of AVA at low doses (0.1–1.0 μM) was observed after 24 h of cotreatment with MMS or CPA at their LC50, causing an increase in HepG2 survival rates. After all, AVA at 10 μM and 25 μM had decreased effect in micronucleus formation in HepG2 cells and restored cell cycle alterations induced by MMS and CPA. This study supports the hypothesis that statins can be chemopreventive agents, acting as antimutagenic, antigenotoxic, and cytoprotective components, specifically against alkylating agents of DNA.

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45

Shunkevich, A. A., A. P. Polikarpov, G. V. Medyak, S. D. Filippovich e Z. I. Akulich. "Synthesis and properties of new strongly basic fibrous anion exchangers". Proceedings of the National Academy of Sciences of Belarus, Chemical Series 58, n. 3 (7 settembre 2022): 286–93. http://dx.doi.org/10.29235/1561-8331-2022-58-3-286-293.

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Abstract (sommario):

A synthesis method of new fibrous anion exchangers with strong base groups has been developed. The synthesis was carried out by alkylation of weakly basic anion exchangers based on polyacrylonitrile fiber using two alkylating agents: epichlorohydrin and ethylene chlorohydrin. The influence of the reaction conditions on the physicochemical properties of new anion exchangers was investigated. The synthesis parameters were determined: the molar ratio of “amino groups: alkylating agent”, the concentration of the alkylating agent, the reaction time and temperature – to obtain anion exchangers with maximum exchange capacity for strong base groups. New strongly basic fibers possess satisfactory mechanical properties allowing their processing into various textile forms.

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46

Allocca, Mariacarmela, Joshua J. Corrigan, Aprotim Mazumder, Kimberly R. Fake e Leona D. Samson. "Inflammation, necrosis, and the kinase RIP3 are key mediators of AAG-dependent alkylation-induced retinal degeneration". Science Signaling 12, n. 568 (12 febbraio 2019): eaau9216. http://dx.doi.org/10.1126/scisignal.aau9216.

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Abstract (sommario):

DNA-alkylating agents are commonly used to kill cancer cells, but the base excision repair (BER) pathway they trigger can also produce toxic intermediates that cause tissue damage, such as retinal degeneration (RD). Apoptosis, a process of programmed cell death, is assumed to be the main mechanism of this alkylation-induced photoreceptor (PR) cell death in RD. Here, we studied the involvement of necroptosis (another programmed cell death process) and inflammation in alkylation-induced RD. Male mice exposed to a methylating agent exhibited a reduced number of PR cell rows, active gliosis, and cytokine induction and macrophage infiltration in the retina. Dying PRs exhibited a necrotic morphology, increased 8-hydroxyguanosine abundance (an oxidative damage marker), and overexpression of the necroptosis-associated genes Rip1 and Rip3. The activity of PARP1, which mediates BER, cell death, and inflammation, was increased in PR cells and associated with the release of proinflammatory chemokine HMGB1 from PR nuclei. Mice lacking the anti-inflammatory cytokine IL-10 exhibited more severe RD, whereas deficiency of RIP3 (also known as RIPK3) conferred partial protection. Female mice were partially protected from alkylation-induced RD, showing reduced necroptosis and inflammation compared to males. PRs in mice lacking the BER-initiating DNA glycosylase AAG did not exhibit alkylation-induced necroptosis or inflammation. Our findings show that AAG-initiated BER at alkylated DNA bases induces sex-dependent RD primarily by triggering necroptosis and activating an inflammatory response that amplifies the original damage and, furthermore, reveal new potential targets to prevent this side effect of chemotherapy.

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47

Posnick, Lauren M., e Leona D. Samson. "Influence of S-Adenosylmethionine Pool Size on Spontaneous Mutation, Dam Methylation, and Cell Growth ofEscherichia coli". Journal of Bacteriology 181, n. 21 (1 novembre 1999): 6756–62. http://dx.doi.org/10.1128/jb.181.21.6756-6762.1999.

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Abstract (sommario):

ABSTRACT Escherichia coli strains that are deficient in the Ada and Ogt DNA repair methyltransferases display an elevated spontaneous G:C-to-A:T transition mutation rate, and this increase has been attributed to mutagenic O 6-alkylguanine lesions being formed via the alkylation of DNA by endogenous metabolites. Here we test the frequently cited hypothesis thatS-adenosylmethionine (SAM) can act as a weak alkylating agent in vivo and that it contributes to endogenous DNA alkylation. By regulating the expression of the rat liver SAM synthetase and the bacteriophage T3 SAM hydrolase proteins in E. coli, a 100-fold range of SAM levels could be achieved. However, neither increasing nor decreasing SAM levels significantly affected spontaneous mutation rates, leading us to conclude that SAM is not a major contributor to the endogenous formation ofO 6-methylguanine lesions in E. coli.

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48

Aikawa, Haruo, Tetsuro Kaneko, Naoki Asao e Yoshinori Yamamoto. "Gold-catalyzed alkylation of silyl enol ethers with ortho-alkynylbenzoic acid esters". Beilstein Journal of Organic Chemistry 7 (20 maggio 2011): 648–52. http://dx.doi.org/10.3762/bjoc.7.76.

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Abstract (sommario):

Unprecedented alkylation of silyl enol ethers has been developed by the use of ortho-alkynylbenzoic acid alkyl esters as alkylating agents in the presence of a gold catalyst. The reaction probably proceeds through the gold-induced in situ construction of leaving groups and subsequent nucleophilic attack on the silyl enol ethers. The generated leaving compound abstracts a proton to regenerate the silyl enol ether structure.

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49

Sabo, T., e M. Onysko. "ALKYLATION OF 3-FORMYLQUINOLINE-2-ONE WITH ALKENYL(ALKYNYL) BROMIDES". Scientific Bulletin of the Uzhhorod University. Series «Chemistry» 51, n. 1 (12 luglio 2024): 76–81. http://dx.doi.org/10.24144/2414-0260.2024.1.76-81.

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Abstract (sommario):

Functional and condensed quinolin-2-one derivatives exhibit a wide range of biological activity. The presence of an aldehyde group and modification at position 1 or 2 of quinolin-2-one expand the searching for new biologically active compounds. One of the directions of such modification is the annulation of an additional azaheterocycle to quinoline. In this work, the interaction of unsaturated alkyl halides (4-bromobut-1-ene, 5-bromopent-1-ene, 5-bromopent-1-yne) with 3-formylquinolin-2-one was investigated. The reaction was carried out in the presence of dimethylformamide using sodium hydride at room temperature or heating to 80°C for 8 hours. It was shown that under the found conditions, non-regioselective alkylation occurs with the formation of a mixture of O- and N-alkylation isomers. According to spectral data, the ratio of alkylation products depends on the alkylating agent. Thus, in case of using 3-formylquinolin-2-one, 4-bromobut-1-ene or 5-bromopent-1-yne, a mixture of O- and N-alkyl quinolines is formed in a ratio of 1:1.5, and in case of 5-bromopent-1-ene - 2:1. N-butenyl-3-formylquinolin-2-one was isolated by fractional crystallization, and in other cases, mixtures with minor amounts of one of the isomers were isolated.

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50

Dong, Guangbin, Hee Lim e Dong Xing. "Transition-Metal-Catalyzed Ketone α-Alkylation and Alkenylation with Simple Alkenes and Alkynes through a Dual Activation Strategy". Synlett 30, n. 06 (21 novembre 2018): 674–84. http://dx.doi.org/10.1055/s-0037-1610315.

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Abstract (sommario):

In this personal account, we summarize our investigations on the α-alkylation and α-alkenylation reactions of ketones with nonactivated alkenes and alkynes, respectively. The serendipitous discovery of C–H alkylation/alkenylation of cyclic 1,2-diketones provided a proof of concept for a dual activation strategy. Extension to the α-alkylation and α-alkenylation of regular ketones was achieved by using 7-azaindoline as a bifunctional ligand. Subsequently, intramolecular coupling between ketones and olefins was achieved with Rh- and Ru-based systems, respectively. Finally, branched-selective α-alkylation was achieved through an Ir-catalyzed enamide-mediated C–H alkylation.1 Introduction2 Serendipitous Discovery of α-Alkylation and α-Alkenylation of 1,2-Diketones through Enamine-Mediated C–H Activation3 Intermolecular Ketone α-Alkylation of Regular Ketones with Nonactivated Olefins4 Intermolecular Ketone α-Alkenylation of Regular Ketones with Nonactivated Alkynes5 Intramolecular Ketone α-Alkylation of Regular Ketones with Nonactivated Olefins6 Branched-Selective α-Alkylation of Regular Ketones with Nonactivated Olefins7 Conclusions and Outlook

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