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Saini, Natalie, Joan F. Sterling, Cynthia J. Sakofsky, Camille K. Giacobone, Leszek J. Klimczak, Adam B. Burkholder, Ewa P. Malc, Piotr A. Mieczkowski und Dmitry A. Gordenin. „Mutation signatures specific to DNA alkylating agents in yeast and cancers“. Nucleic Acids Research 48, Nr. 7 (05.03.2020): 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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Garcia-Ramos, Yesica, Caroline Proulx und William D. Lubell. „Synthesis of hydrazine and azapeptide derivatives by alkylation of carbazates and semicarbazones“. Canadian Journal of Chemistry 90, Nr. 11 (November 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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Hadzic, Pavle, Mirjana Popsavin und Suncica Borozan. „Alkylating ability of carbohydrate oxetanes: Practical synthesis of bolaform skeleton derivative“. Journal of the Serbian Chemical Society 80, Nr. 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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McIntosh, John M., und Pratibha Mishra. „Alkylation of camphor imines of glycinates. Diastereoselectivity as a function of electronic factors in the alkylating agent“. Canadian Journal of Chemistry 64, Nr. 4 (01.04.1986): 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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Shimkin, Kirk W., und Donald A. Watson. „Recent developments in copper-catalyzed radical alkylations of electron-rich π-systems“. Beilstein Journal of Organic Chemistry 11 (23.11.2015): 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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Platzek, T., G. Bochert, U. Rahm und D. Neubert. „Embryotoxicity Induced by Alkylating Agents. Some Methodological Aspects of DNA Alkylation Studies in Murine Embryos Using Ethylmethanesulfonate“. Zeitschrift für Naturforschung C 42, Nr. 5 (01.05.1987): 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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Goryunova, Alexandra Konstantinovna, Nina Sergeevna Baklan, Galina Vladimirovna Timofeeva und 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, Nr. 3 (29.09.2023): 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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Kaliendina, S., M. Brynzei, M. Kut, S. M. Sukharev, Е. Ostapchuk und 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, Nr. 2 (22.01.2024): 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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Alagoz, Meryem, Owen S. Wells und 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, Nr. 5 (12.12.2013): 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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Yoshikai, Naohiko, und Ke Gao. „Cobalt-catalyzed directed alkylation of arenes with primary and secondary alkyl halides“. Pure and Applied Chemistry 86, Nr. 3 (20.03.2014): 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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The work described in this thesis has been directed at the development of a novel synthetic route to alkylsalicylic acids. Associated reactions have also been studied. The primary aim has been the synthesising of alkylsalicylic acids possessing an alkyl chain containing more than eight carbon atoms. In addition, a limited study has also been carried out into the sulfurisation of alkylphenols. Both the alkylsalicylic acids and the sulfurised aJkylphenols are used as oil additives. They both act as detergents, keeping an engine clean and neutralising any acids formed in the engine as a result of oxidation processes. Chapter Icontains a general introduction to oil additives, principally the overbased detergents, and an introduction to Friedel-Crafts chemistry, which is the basic reaction employed in the alkylation of salicylic acid. Chapter 2 introduces the alkylation of salicylic acid employing concentrated sulfuric acid as the catalyst, and using simple model compounds to demonstrate the feasibility of the approach. The effect of varying the alkylating substrate to produce an alkylsalicylic acid with an alkyl chain containing at least eight carbon atoms is explored in Chapter 3. Optimization of the alkylation reaction and the effect of altering a number of the reaction parameters (e.g. temperature, catalyst and reaction duration) on the yield and product distribution for a range of alkylating substrates is set out in Chapter 4. The work contained in Chapter 5 concentrates on the synthesis and rearrangement of the esters of salicylic acid and investigates the possibility that the esters are intermediates in the alkylation reaction. Chapter 6 is concerned with the industrial implications of the alkylation of salicylic acid. It concentrates in particular on the synthesis using industrially available alkenes and the scale-up of the reaction. An insight into the sulfurisation of alkylphenols, and the attempted identification of products formed in the industrial process, can be found in Chapter 7. Finally, the experimental details for Chapters 2 to 7 are contained in Chapter 8.
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A novel camphor-derived hydroxy ketal 138 has been developed as a crural auxiliary, and used to prepare a series of six carboxylic esters of increasing steric bulk. The α-benzylation of this series of esters was achieved with diastereoselectivities of 59 - 83％ d. e. and in 39 - 48％ material yield. These results compared very favourably with those obtained in earlier studies using a regioisomeric analogue as the chiral auxiliary. Computer.modelling studies of the putative enolate intermediate has provided some insight into the possible mode of electrophilic attack at the α-carbon and the roles of the ketal protecting group and the lithium cation in these asymmetric transformations. In a related investigation, based on earlier work, a camphor-derived imino lactone has provided convenient access to α-alkyl α-amino acids, the imino lactone serving as a masked glycine equivalent. Using straight chain primary alkyl iodides [RI; R = Me, Et, Pr, Bu, CH₃(CH₂)₄ and CH₃(CH₄)₅], alkylation of the potassium enolate of the camphor-derived imino lactone was effected with 54 - 89％ d.e. and in 54 - 87％ material yield. Four novel alkylated derivatives were synthesised using isopropyl iodide, sec-butyl iodide and allyl iodide, the latter reagent resulting in both the monoallylated and diallylated products. While very good diastereoselectivities were achieved (83 - 88％ d. e.) in these reactions, the material yields from reaction with the secondary alkyl iodides were low (31- 35％) due, presumably, to their decreased electrophilicity. Computer modelling studies of the enolate were carried out and support the hypothesis of endo attack by the electrophile on the enolate intermediate. These studies also indicate the possibility of coordination of the postassium cation to the endocyclic ester oxygen, thus effectively anchoring the bulky cation away from the reaction site.
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Bisnaire, Michel M. J. „Iron-mediated allylic alkylation reactions“. Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5797.
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In this work it will be shown that Fe(CO)$\sb2$(NO)$\sb2$ mediated allylic alkylation reactions proceed via an intermediate which is neither an $\eta\sp3$-allyliron complex nor an $\eta\sp2$-allyliron complex. Rather, (Fe(CO)(NO)$\sb2$DMM)$\sp-$Na$\sp+$ has been identified as the catalytic intermediate. This provides the first evidence of an interaction between the nucleophile and the metallic center in reactions involving iron nitrosyl complexes. The study of the Fe(CO)$\sb3$(NO)$\sp-$Na$\sp+$, geranyl acetate, and NaDMM system was studied in order to elucidate the catalytically active species. Although it was determined that Fe(CO)$\sb3$(NO)$\sp-$Na$\sp+$ served as the precursor of a catalytic species X, the nature of X remains unknown.
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Walsh, Kelly Ann. „The alkylation of aromatic amines“. Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7659.
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N-alkylated anilines can be obtained in moderate yields from aniline and methyl formate in the presence of Rh$\sb6$(CO)$\sb $ and KI after 72 hours at 180-200$\sp\circ$C. Ru$\sb3$(CO)$\sb $ gave similar results to the unpromoted rhodium carbonyl system. Formanilide and N-methylformanilide were also formed in the reaction. The (HCr(CO)$\sb5$) -anion in the form of its PPN$\sp+$ and Et$\sb4$N$\sp+$ salts also catalysed this reaction (under hydrogen) but was selective to the formanilide products. The presence of an electron donating group on the aromatic ring favoured the formation of alkylated products in the presence of bis(triphenylphosphine)iminium (PPN$\sp+$) hydridochromiumpenta-carbonyl. Several possible mechanisms were tested and the nature of the polynuclear catalysts investigated.
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El, Gihani Moharem Taha. „Aspects of some alkylation reactions“. Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/10420.
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Friedel-Crafts reactions of the (-)-8-phenylmenthyl and (+ )-trans-2-(acumyl) cycJohexyl aryl hydroxy acetates catalysed by trimethylsilyl triflate (TMSOTf) and equivalents in the presence of electron rich heterocycles gave the expected diarylacetates in high de 88%, via a planar cation. The interaction of trifluoromethanesulfonic (triflic) acid (TfOH) with either bistrimethylsilyl -acetamide (BSA) or -urea (BSU) can be used to generate stoichiometric amounts of trimethylsilyl triflate (TMSOTf) "in situ" , the system can be used efficiently to remove triflic acid from TMSOTf and to generate catalytic amounts of TMSOTf from TfOH for use in a range of trimethylsilyl triflate (TMSOTf) catalysed reactions. Similarly the interaction of fluorosulfonic acid (FSA) with either bis-trimethylsilyl -acetamide (BSA) or -urea (BSU) can be used to generate catalytic amounts of trimethylsilylfluorosulfonate (TMSOFs) "in situ" for use in a wide range of reactions as an alternative to trimethylsilyltriflate (TMSOTf) Scandium(III) trifluoromethanesulfonate and copper(II) trifluoromethanesulfonate can be used to catalyse aromatic alkylation with arylhydroxyacetates. Scandium(III) trifluoromethanesulfonate also proved to be a recyclable catalyst for these reactions. A number of Pictet-Spengler cyclisation reactions were also catalysed by Scandium(III) trifluoromethanesulfonate and copper(II) trifluoromethanesulfonate. Mannich reactions of a number of caJix[4jresorcinarene derivatives with (R)-(+)-amethylbenzylamine under alkaline conditions lead to the formation of single diastereomeric tetrakis(l,3-dihydrobenzoxazine) derivatives in high yields; the reactions using the (S)-(-)-a-methylbenzylamine afford the enantiomers. The products react with protic acids to afford equilibrium mixtures of diastereomers.
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Evans, Louise Anne. „Ion-pairing in allylic alkylation“. Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529850.
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Loaring, Huw W. „Alkylation studies on the gibberellins“. Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338439.
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La reaction d'alkylation isobutane/butene-1 a ete etudiee a basse temperature, en utilisant un catalyseur a base d'acide sulfurique concentre, depose sur silice. L'etude bibliographique de la reaction constitue le premier chapitre de cette these. La premiere partie est consacree aux aspects mecanistiques de la reaction, aux catalyseurs d'alkylation et aux procedes industriels. Les themes suivants sont developpes dans la deuxieme partie: activite catalytique, mise en evidence du role des sulfates de butyle et etudes cinetiques. Le second chapitre presente le systeme catalytique utilise et decrit les modes operatoires. Le chapitre iii propose un mecanisme pour l'etage d'initiation du catalyseur, a l'issue d'une etude sur le role des sulfates de butyle secondaires et tertiaires. Le chapitre iv demontre que la reaction cinetiquement limitante de l'alkylation est une reaction de volume pendant la periode d'initiation et une reaction interfaciale a l'etat de regime. Le chapitre v est consacre a l'effet de l'acidite sur la selectivite de l'alkylat. Une modelisation permettant de prevoir la selectivite en trimethylpentanes, a t = -5c, pour une large gamme de granulometries et de compositions de phase acide, est proposee. L'effet de l'acidite sur les reactions secondaires de degradation de l'alkylat a egalement ete evoque, dans le cadre d'une etude cinetique sur la degradation du trimethylpentane-2,2,4
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Chumbhale, V. R. „Alkylation reactions over synthetic zeolites“. Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1992. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5828.
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American Petroleum Institute. Refining Dept. Safe operation of hydrofluoric acid alkylation units. Washington, D.C. (1220 L St., N.W., Washington 20005): American Petroleum Institute, 1992.
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1887-1982, Challenger Frederick, Craig P. J. 1944-, Glockling F, Royal Society of Chemistry (Great Britain) und Biochemical Society (Great Britain), Hrsg. The Biological alkylation of heavy elements: The proceedings of a conference commemorating the centenary of the birth of Professor Frederick Challenger. London: Royal Society of Chemistry, 1988.
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J, Craig P., und Glockling F, Hrsg. The biological alkylation of heavy elements: The proceedings of a conference commemorating the centenary of the birth of Professor Frederick Challenger ... London 17th-18th September 1987. London: Royal Society of Chemistry, 1988.
Larock, Richard C. „Alkylation“. In Reactivity and Structure Concepts in Organic Chemistry, 249–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-70004-0_6.
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Gooch, Jan W. „Alkylation“. In Encyclopedic Dictionary of Polymers, 28. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_446.
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Matar, Sami, Manfred J. Mirbach und Hassan A. Tayim. „Alkylation Processes“. In Catalysis in Petrochemical Processes, 66–83. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-1177-2_4.
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Simakova, Olga A., Robert J. Davis und Dmitry Yu Murzin. „N-Alkylation“. In SpringerBriefs in Molecular Science, 35–37. Heidelberg: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-00906-3_4.
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Alkylation is the transfer of an alkyl group (CnH2n+1) from one molecule (alkylating agent) to another where it can attach typically to carbon (C-alkylation), but also to oxygen (O-alkylation), nitrogen (N-alkylation), sulfur (S-alkylation) and phosphorous (P-alkylation) depending on the reaction conditions. This chapter discusses the importance of alkylation reactions, then looks at green improvements made by using solid acid catalysts, ionic liquids in Friedel–Crafts reactions, the atom economic borrowing hydrogen strategy and directed alkylation of C–H bonds using alkenes.
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Frey, Perry A., und Adrian D. Hegeman. „Alkyltransferases“. In Enzymatic Reaction Mechanisms. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195122589.003.0019.
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A number of enzymes catalyze alkylation reactions, most of which are reactions of S-adenosyl-L-methionine (SAM) as a methylating agent in the biosynthesis of hormones, modification of DNA, and methyl esterification of proteins involved in signal transduction. Other examples of enzymatic alkylation include prenyl transfer reactions, adenosyltransfer from ATP to methionine in the biosynthesis of SAM, and adenosyltransfer from ATP to cob(I)alamin in the biosynthesis of adenosylcobalamin. Methyl group transfer is also the essential step in the reaction of methionine synthase, which uses 5-methyltetrahydrofolate as an alkylating agent. In an analogous reaction, an analog of 5-methyltetrahydrofolate is the methyl group donor in the methylation of coenzyme M to form methyl coenzyme M, the proximate precursor of methane in methanogenesis (see chap. 4). Glysosyl transfer is an alkylation reaction catalyzed by a large class of enzymes, the glycosyltransferases and glycosidases. The special nature of the glycosyl compounds and their potential for undergoing glycosyltransfer places them in their own class in biochemistry (see chap. 12). The reactivity of glycosyl compounds can be attributed to the contribution of the oxygen atom directly bonded to the glycosyl carbon, the locus of alkylation. In this chapter, we consider other enzymatic alkylations. Alkylation consists of the transfer of a carbon from a leaving group to a nucleophilic acceptor, as in eq.15-1, where R is H or an organic group. The rate is controlled by the reactivity of the nucleophile X:, the stability of the leaving group Y:, and the electrophilic reactivity of the central carbon atom. Alkylation may be regarded as one of the simplest organic chemical reactions because there are few complications in the mechanism. It is the reaction of a nucleophilic molecule with an electrophilic molecule to displace a leaving group. Enzymatic alkylations proceed by polar and not radical mechanisms. In organic chemistry, polar alkylation can occur either by an associative or one-step mechanism, as in fig. 15-1A, or by a dissociative or two-step mechanism through a carbocationic intermediate, as in fig. 15-1B. The chemical nature of the alkylating agent, the propensity of the leaving group to leave, and the polarity of the solvent determine the mechanism.
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Clayden, Jonathan, Nick Greeves und Stuart Warren. „Alkylation of enolates“. In Organic Chemistry. Oxford University Press, 2012. http://dx.doi.org/10.1093/hesc/9780199270293.003.0025.
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This chapter studies the alkylation of enolates. The alkylations in the chapter each consists of two steps. The first is the formation of a stabilized anion—usually (but not always) an enolate—by deprotonation with base. The second is a substitution reaction: attack of the nucleophilic anion on an electrophilic alkyl halide. All the factors controlling SN1 and SN2 reactions are applicable here. Problems that arise from the electrophilicity of the carbonyl group can be avoided by replacing C=O by functional groups that are much less electrophilic but are still able to stabilize an adjacent anion. The chapter then looks at the alkylation of nitriles and nitroalkanes.
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Fahim, Mohamed A., Taher A. Alsahhaf und Amal Elkilani. „Alkylation“. In Fundamentals of Petroleum Refining, 263–83. Elsevier, 2010. http://dx.doi.org/10.1016/b978-0-444-52785-1.00010-3.
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„Alkylation“. In Encyclopedia of Genetics, Genomics, Proteomics and Informatics, 58. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6754-9_494.
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Konferenzberichte zum Thema "Alkylation":
1
Matsushita, Yoshihisa, Mayuko Iwasawa, Nobuko Ohba, Shinji Kumada, Tadashi Suzuki und Teijro Ichimura. „Photocatalytic Oxidation and Alkylation Processes in Microreactors“. In 2007 2nd IEEE International Conference on Nano/Micro Engineered and Molecular Systems. IEEE, 2007. http://dx.doi.org/10.1109/nems.2007.352152.
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Chsherbakova, Yuliya, Irena Dolganova und Nalaliya Belinskaya. „Benzene alkylation with ethylene process mathematical modeling“. In 2012 7th International Forum on Strategic Technology (IFOST). IEEE, 2012. http://dx.doi.org/10.1109/ifost.2012.6357494.
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Hameed, Shymaa Ali, Amer T. Nawaf und Aysar T. Jarullah. „Optimal operation of an industrial alkylation reactor“. In 3RD INTERNATIONAL CONFERENCE ON ENERGY AND POWER, ICEP2021. AIP Publishing, 2022. http://dx.doi.org/10.1063/5.0107704.
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Simonton, Julie L., und Leon K. Barry. „Evolution of New Gasket Type Increases Reliability in HF Alkylation Unit“. In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93119.
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The evolution of a new gasket type for use in Hydrofluoric (HF) Alkylation Units from the standard HF alkylation spiral-wound type gasket, (Monel windings, PTFE filler, and outer carbon steel ring) to a more specialized and robust gasket type was driven by a need to minimize flange face corrosion, overcome handling limitations and improve sealing performance. Protecting the carbon steel flange face from aggressive HF acid corrosion and resulting iron fluoride scaling, while increasing both the reliability and sealability of an HF connection was achieved, preventing costly flange damage, potential leakage and associated unit shutdowns required for repairs. This paper highlights the journey taken by a major petrochemical company in determining the solution to improving gasket durability and leakage prevention, while significantly reducing flange face corrosion in their HF alkylation units.
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Stepin, S. N., T. A. u. Holmurodov und O. O. u. Mirzaev. „ОРГАНИЧЕСКИЙ СИНТЕЗ ВЫСОКОМОЛЕКУЛЯРНЫХ СОЕДИНЕНИЙ“. In Nauka. Issledovaniia. Praktika: sbornik izbrannyh statei po materialam Mezhdunarodnoi nauchnoi konferencii (Sankt-Peterburg, Fevral` 2020). ГНИИ "Нацразвитие", 2020. http://dx.doi.org/10.37539/srp289.2020.13.60.005.
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в данной работе приводятся результаты исследования реакции алкилирования 2-тиоксо-6-фенилпиримидин-4-она алкилгалогенидами C4-C9. Показано, что в зависимости от условий реакции и соотношения реагентов образуются продукты N-3 алкилированияthis article presents the results of the alkylation reaction of 2-thio-6- phenylpyrimidin-4-one with C4-C9 alkyl halides. The results show that, depending on the reaction conditions and the ratio of reagents, N-3 alkylation products are formed.
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Pogrebnoi, Vsevolod, Serghei Pogrebnoi und Fliur Macaev. „The alkylation of the amides of dehydroabietic acid“. In Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab08.
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In this abstract is being discussed the synthesis of new substituted amides of dehydroabietic acid with different bromides in system K2CO3/DMF. It is known fact that many compounds, such as famous isatine 1, have the amide group in its molecule. There is no point in talking about it, because everything is known regarding chemical properties. However, what if there are two amide groups in the molecule at once? Let us see… For our investigation, we used the model of well-known alkylation reaction [1]. As starting material, we used two types of bromide: aliphatic and aromatic – bromoacetone [2] and phenacyl bromide [3], respectively, which reacted with dioxalane 2 [4] in above described conditions [4].The first approach was started from slight excess of corresponding bromide (1.2-1.3 eq.) and the full conversion observed after 3 hours at 40-500C. According to NMR spectrum, the isolated white solids are monosubstituted products – 3 and 4, respectively [4]. Increasing the amount of bromide to 3-4 equivalents didn't change the situation – the TLC showed only monosubstituted compounds. And the last approach was in significantly increasing the amount of bromide (up to 10 equivalents) and heating the reaction mixture above 1000C for several days, resulting a significant drop in the yield of the desired products and the formation of by-products that could not be isolated and characterized. The formation of monosubstituted products can be explained by steric factors – the close location of methyl and carbonyl group to the reaction center at the nitrogen atom in dehydroabietic fragment.
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Ahmed, Duraid Fadhil, und Qahatan Adnan Mahmood. „Self-tuning control of alkylation in batch reactor“. In 2012 First National Conference for Engineering Sciences (FNCES). IEEE, 2012. http://dx.doi.org/10.1109/nces.2012.6740469.
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Poli, Giovanni, Giuliano Giambastiani und Barbara Pacini. „First Pd(0)-Catalyzed (Allylic Alkylation / Heck) Domino Sequence“. In The 4th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2000. http://dx.doi.org/10.3390/ecsoc-4-01840.
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Kawabata, Takeo, Hideo Suzuki, Yoshikazu Nagae, Thomas Wirth, Kyoshi Yahiro und Kaoru Fuji. „Memory of Chirality in Alkylation of a-Amino Acid Derivatives“. In The 4th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2000. http://dx.doi.org/10.3390/ecsoc-4-01872.
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Sapaev, B., I. B. Sapaev, F. E. Saitkulov, A. A. Tashniyazov und D. Nazaraliev. „Synthesis of 2-methylquinazoline-4-thione with the purpose of alkylation of 3-propyl 2-methylquinazoline-4-thione with alkylating agents“. In 2021 ASIA-PACIFIC CONFERENCE ON APPLIED MATHEMATICS AND STATISTICS. AIP Publishing, 2022. http://dx.doi.org/10.1063/5.0089924.
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Vicic, David A. Final Technical Report [Development of Catalytic Alkylation and Fluoroalkylation Methods]. Office of Scientific and Technical Information (OSTI), Mai 2014. http://dx.doi.org/10.2172/1130313.
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Uibel, Rory, H., Lee M. Smith und Robert, E. Benner. Raman Scattering Sensor for Control of the Acid Alkylation Process in Gasoline Production. Office of Scientific and Technical Information (OSTI), April 2006. http://dx.doi.org/10.2172/881280.
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Ray, Rahul. Alkylating Derivatives of Vitamin D Hormone for Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, Oktober 2010. http://dx.doi.org/10.21236/ada538552.
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Ray, Rahul. Alkylating Derivatives of Vitamin D Hormone for Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, Oktober 2008. http://dx.doi.org/10.21236/ada506555.
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Ray, Rahul. Alkylating Derivatives of Vitamin D Hormone for Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, Oktober 2009. http://dx.doi.org/10.21236/ada513335.
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Ray, Rahul. Alkylating Derivatives of Vitamin D Hormone for Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, Oktober 2006. http://dx.doi.org/10.21236/ada462093.
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Ray, Rahul. Alkylating Derivatives of Vitamin D Hormone for Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, Oktober 2007. http://dx.doi.org/10.21236/ada477181.
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Kuo, Shue-Ru, und Thomas Melendy. DNA Replication Arrest and DNA Damage Responses Induced by Alkylating Minor Groove Binders. Fort Belvoir, VA: Defense Technical Information Center, Mai 2001. http://dx.doi.org/10.21236/ada395141.
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Smulson, Mark E. The Molecular Biological Basis for the Response of Poly(ADP-RIB) Polymerase and NAD Metabolism to DNA Damage Caused by Mustard Alkylating Agents. Fort Belvoir, VA: Defense Technical Information Center, Juli 1996. http://dx.doi.org/10.21236/ada319494.
