Arylmethyl Halides Research Articles

Regioselective synthesis of 1-allyl- and 1-arylmethyl uracil and thymine derivatives

2,4-Bis(trimethylsiloxy) pyrimidines 1 with allyl halides and arylmethyl halides in 1,2-dichloroethane in the presence of I 2 regioselectively provide 1-allyl-/1-arylmethyl-uracil and thymine derivatives. The secondary aryl alkyl and diaryl methyl halides with 1 provide chiral 1-arylalkyl/1-(diarylmethyl) uracil/thymine derivatives. The procedure has been extended to the synthesis of fluorescent uracil/thymine derivatives.

Selective Photosubstitution Reactions of Tertiary 1-Alkyl-1,1-diarylmethyl Chloride: Simultaneous Formation of Radicals and Carbocations from the Excited State of 1-Alkyl-1,1-diarylmethyl Chloride

Department of Chemistry, Kyungpook National University, Daegu 702-701, KoreaReceived May 6, 2003Key Words : Excited state partition, Heterolysis, Homolysis, Selective photosubstitution, 2,2,2-Trifluoro-1,1-diarylethyl chloridePhotochemical reactions of arylmethyl halides are inter-esting and invaluable in synthetic methods because of apossible complement for thermal reactions and in their ownrights. In 1963, Zimmerman and Sandel

Preparation of novel 3,7-, 7,9- and 1,7-disubstituted guanines

Treatment of guanosine with arylmethyl halides in N, N-dimethylacetamide results in a series of 3,7-bis(arylmethyl) guanines and 7,9-bis(arylmethyl)guaninium halides. The same reaction on 7-arylmethyl guanines yields 3,7- and 7,9- differently disubstituted guanines. When 7-arylmethyl guanines are reacted with (hetero)arylmethyl halides in the presence of sodium hydride in N, N-dimethylformamide, 3,7- and 1,7-disubstituted guanines are obtained. All of these compounds, but one, are new and the preparation of 3,7-bis(substituted) guanines from guanosine as well as of 3,7- and 1,7-di(hetero)arylmethyl guanines from 7-substituted guanine is unprecedented.

Application of cationic polymerization to grafting and coating of silica particles

AbstractThe cationic polymerization of electron rich monomers such as vinyl ethers, vinyl furane, and cyclopentadiene on silica surfaces can be initiated by aryl methyl halides. The reactions yield always soluble polymers (by heterogeneous catalysis) and novel polymer/silica hybrid materials. The link between polymer and solid is caused by covalent Si‐O‐C bonds, by network formation of the polymers during the chain growth, or by a combination of both of them. The analysis of the polymer structures on the surface by 1H MAS NMR spectroscopy in suspension and by solid state 13C CP MAS NMR spectroscopy is described. Proof of Si‐O‐C bonds via DRIFT spectroscopy and 13C CP MAS NMR spectroscopy is given. The most effective method of irreversibly linking the polymer to the silica surface is the network formation. Polyvinyl ethers are bound strongly to the surface, as can be shown by FTIR measurements, but the linkage is not stable due to the Si‐O‐C bonds' susceptibility to hydrolysis.Poly‐cyclopentadienes (PCPD) are linked to the surface by Si‐O‐C bonds, which show an extraordinary high resistance to acids and bases. Si‐O‐C bond formation of poly‐2‐vinyl furane could not yet be detected by 13C CP MAS NMR spectroscopy and DRIFT spectroscopy. In this case the high degree of coating derives from the bifunctionality of 2‐vinyl furane: it may undergo Friedel‐Crafts‐alkylation at the 5‐position of the furane ring as well as chain polymerization via the vinyl group at the 2‐position.

Cationic Initiation of Vinyl Ether Polymerization Induced by (4-RC6H4)(4-RC6H4)RCX in Conjunction with Silica: Producing Highly Head Group Functionalized Polymers

Addition of vinyl ethers to arylmethyl halides and silica at 0 and −78 °C results in the formation of polymers. The average molecular weight, the molecular weight distribution (MWD), and the head group functionality are strongly dependent on the structure of the arylmethyl halide and on the olefin/arylmethyl halide ratio. The heterogeneous induced polymerization depends not only on the temperature but also on the kind of silica used, e.g. Aerosil (Degussa) and Kieselgel 60 (KG 60) (Merck). We found that initiation with carbocations of the type (4-R1C6H4)(4-R2C6H4)R3C+ (R1, R2 = H, CH3, OCH3; R3 = H, C6H5) with an electrophilicity in the range of −5 > pKR+ > −9 bearing a chloride counterion yields highly head group functionalized polymers. General mechanisms for the initiation and propagation step of the surface-mediated cationic vinyl ether polymerization considering the influence of the counterion and the initiating carbocation are discussed.

Estimation of bond energy in radical anions of arylmethyl halides as the controlling factor of stepwise versus concerted reductive cleavage

The ionic component of the bond energy in a series of the title radical anions was calculated on the basis of absolute electronegativity and hardness. A linear correlation of the estimated bond-dissociation energy D(RX ·-) in radical anions versus the energy E LUMO in parent halides was found, with separate areas for reactants giving the stepwise and concerted reductive cleavage. The higher D(RX ·- energy corresponds to the larger preference for the stepwise mechanism, in agreement with thermodynamic as well as kinetic considerations.

ChemInform Abstract: Electron Transfer and Bond Breaking. Examples of Passage from a Sequential to a Concerted Mechanism in the Electrochemical Reductive Cleavage of Arylmethyl Halides

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Electron transfer and bond breaking. Examples of passage from a sequential to a concerted mechanism in the electrochemical reductive cleavage of arylmethyl halides

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron transfer and bond breaking. Examples of passage from a sequential to a concerted mechanism in the electrochemical reductive cleavage of arylmethyl halidesClaude P. Andrieux, Annie Le Gorande, and Jean Michel SaveantCite this: J. Am. Chem. Soc. 1992, 114, 17, 6892–6904Publication Date (Print):August 1, 1992Publication History Published online1 May 2002Published inissue 1 August 1992https://doi.org/10.1021/ja00043a039RIGHTS & PERMISSIONSArticle Views1136Altmetric-Citations240LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

ChemInform Abstract: Single Electron Transfer Initiated Thermal Reactions of Arylmethyl Halides. Part 16. The Reaction of Triphenylmethyl Halides with Triphenylphosphine in Cumene and tert‐Butylbenzene.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Calixarenes. 29. Aroylation and arylmethylation of calix[6]arenes

Aroylations and arylmethylations of p-tert-butylcalix6arene have been carried out using a variety of parasubstituted aroyl chlorides and arylmethyl halides to determine the effect of para substituents on the structural and/or conformational outcome of the reactions. When an excess of derivatizing agent is used with NaH as the base the products in all cases are the 1,2,4,5-tetrasubstituted compounds in the 1,2,3-alternate conformation

Theoretical models for the reduction of arylmethyl halides by triorganotin hydrides

Two mechanistic pathways have been proposed for halogen atom transfer from the benzylic positions of halomethylarenes to triorganotin radicals. These are direct atom abstraction, which might involve an extremely polar transition state, and single electron transfer followed by bond cleavage. AM1 semi-empirical calculations have been utilized to model the rate-determining step of these processes. A wide range of related families of compounds have been studied, including substituted halomethylbenzes, selected halomethyl-substituted polycyclic aromatic hydrocarbons and oxygen- and nitrogen-containing chloromethyl-substituted heteroaromatic systems. Although these calculations are relatively simple, the present results corroborate the view that chlorine and bromine atom transfer from the benzylic position to triorganotin radicals involves a direct atom abstraction in the rate-determining step whereas reduction of the corresponding iodides proceeds via an electron-transfer mechanism.

ChemInform Abstract: Single Electron Transfer Initiated Thermal Reactions of Arylmethyl Halides. Part 14. The Reaction of Triphenylmethyl Halides with Tributylphosphine and Tributylamine in Apolar Solvents.

AbstractPh3CBr (I) (and similarly, but much slower, Ph3CCl (V)) reacts with Bu3P (II) (and analogously with Bu3N) in aromatic hydrocarbons by single electron transfer.

ChemInform Abstract: Single Electron Transfer Initiated Thermal Reactions of Arylmethyl Halides. Part 13. Reactions of Some p‐Substituted Triphenylmethyl Chlorides with Alcohols, Alkali‐Metal Alcoholates, and Tributylamine.

AbstractThe triarylmethyl chlorides (I) react with methanol (II) to give the products (III) (via hydride transfer to the corresponding triarylmethylium cations) and (IV) (via polar substitution).

Synthesis of 3-(3-pyridyl)- and 3-(3-benzo[b]thienyl)-D-alanine.

The DL-arylamino acid ethyl ester derivatives of beta-(3-pyridyl)-DL-alanine, and beta-(3-benzo[b]thienyl)-DL-alanine were synthesized by diethyl acetamidomalonate condensation with the respective arylmethyl halides followed by partial hydrolysis to the monoethyl ester and decarboxylation. Each derivative was enzymatically resolved to a separable mixture of the corresponding N-acetyl-L-amino acid and the unchanged D amino acid derivative. Acidic hydrolysis of the latter gave the corresponding D-amino acid, the optical purity of which was established by HPLC analysis of the 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC) derivative. The free D amino acids were converted to D-BOC derivatives by reaction with di-tert-butyldicarbonate in tert-butyl alcohol, water and sodium hydroxide.

ChemInform Abstract: SINGLE‐ELECTRON‐TRANSFER‐INITIATED THERMAL REACTIONS OF ARYLMETHYL HALIDES. PART 11. THE REACTION OF TRITYL HALIDES WITH SODIUM METHOXIDE IN 2,2‐DIMETHOXYPROPANE

Chemischer InformationsdienstVolume 16, Issue 52 Preparative Organic Chemistry ChemInform Abstract: SINGLE-ELECTRON-TRANSFER-INITIATED THERMAL REACTIONS OF ARYLMETHYL HALIDES. PART 11. THE REACTION OF TRITYL HALIDES WITH SODIUM METHOXIDE IN 2,2-DIMETHOXYPROPANE P. HUSZTHY, P. HUSZTHYSearch for more papers by this authorK. LEMPERT, K. LEMPERTSearch for more papers by this authorG. SIMIG, G. SIMIGSearch for more papers by this author P. HUSZTHY, P. HUSZTHYSearch for more papers by this authorK. LEMPERT, K. LEMPERTSearch for more papers by this authorG. SIMIG, G. SIMIGSearch for more papers by this author First published: December 31, 1985 https://doi.org/10.1002/chin.198552095Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue52December 31, 1985 RelatedInformation

Single‐electron Transfer‐initiated Thermal Reactions of Arylmethyl Halides, IX. The Reaction of 2‐Bromo‐ N , N ‐dimethyl‐2,2‐diphenylacetamide with Triethylamine in Benzene

Durch Ein-Elektronen-Übergang ausgelöste thermische Reaktionen von Arylmethylhalogeniden, IX. Die Reaktion von 2-Brom-N,N-dimethyl-2,2-diphenylacetamid mit Triethylamin in Benzol Das Halogenamid 1a liefert mit Triethylamin in siedendem Benzol 41 – 48% des Dimeren 3 als Hauptprodukt. Andererseits führt die Thermolyse von 1f in Benzol in Gegenwart von Triethylamin zu 1c und 8a. Die Bildung von 3 erfolgt über die Radikale 4, die ihrerseits das Produkt einer Ein-Elektronen-Übergangs-Reaktion mit Triethylamin als Elektron-Donor [Gl. (1)] sind. Der Übergang der Radikale 4 in das Dimere 3 verläuft entsprechend der Reaktionsfolge (2) + (4) + (5) (carbanionischer Mechanismus der Dimeren-Bildung).

Single-electron-transfer-initiated thermal reactions of arylmethyl halides. Part 11. The reaction of trityl halides with sodium methoxide in 2,2-dimethoxypropane

Trityl chloride (1a) and bromide (1b) furnish with sodium methoxide in 2,2-dimethoxypropane, in addition to several minor products, mixtures of the substitution products methyl trityl ether (1c) and p-methoxytriphenylmethane (2a), and of the reduction products triphenylmethane (1f) and p-diphenylmethyltritylbenzene (3a) which are the products of competing SN and single-electron-transfer-initiated processes. Compound (1c) is suggested to be formed via two successive SN′ processes rather than by either the SN1 or SN2 mechanisms which are both disfavoured under the experimental conditions applied.

Single-electron transfer-initiated thermal reactions of arylmethyl halides. Part 8. The reaction of 2-halogeno-NN-dimethyl-2,2-diphenylacetamides with sodium methoxide in 2,2-dimethoxypropane. The effects of added acetone, temperature elevation, and of the nature of the halogen. Refinement of the reaction mechanism

In addition to the previously isolated products (1c) and (2a), trimeric (2b) and oligomeric products (2c) were shown to result from the title reaction. The reactions leading to all these products are initiated by single-electron transfer (SET) to the halogenoacetamides (1a and b). The operation of chain processes is established (Scheme 4). Acetone enolate is shown to be a more effective single-electron donor towards compound (1a) than methoxide. In the absence of acetone enolate SN reactions with methoxide compete with SET-initiated reactions of compound (1a) at room temperature. Temperature elevation favours SET over SN reactions. The mechanism of trimer (2b) and oligomer (2c) formation is discussed and, in addition to the radical recombination mechanism, the carbanionic mechanism of dimer (2a) formation is established. The chloro derivative (1b) is shown to be less reactive in the title reaction than the bromo analogue (1a).

ChemInform Abstract: STUDIES ON 1,2,3,4‐TETRAHYDROISOQUINOLINES. II. A ONE‐POT SYNTHESIS OF 1‐ARYLMETHYL‐1,2,3,4‐TETRAHYDROISOQUINOLINES FROM AN ISOQUINOLINIUM SALT

AbstractIn einem Eintopfverfahren läßt sich das Benzylisochinoliniumbromid (I) zu den Tetrahydroisochinolinen (III) umsetzen.

Synthesis of aryltrifluoromethylacetylenes

Aryltrifluoromethylacetylenes were synthesized by an intramolecular Wittig reaction of trifluoroacetylarylidenephosphoranes, which were synthesized from arylmethyl halides.