Transfer Cyclization Reactions Research Articles

Design and synthesis of novel cyclopeptide p53-MDM2 inhibitors with isoindolinone as antitumor agent

In this paper, two kinds of novel p53 cyclopeptides containing 1-Phe, 2-Trp, 3-Leu, 4-Leu/Pro residues and isoindolinone were synthesized by intramolecular photoinduced single electron transfer cyclization reactions, and their structures were confirmed by 1H NMR, 13C NMR and HR-MS. Comparison of bioactivity of compound 1 and 2 against HeLa, HepG-2, MDA-MB, MCF-7 and 4T1 cell lines by MTT assay, indicated moderate antiproliferative activity of compound 2 (4-Pro). Moreover, compound 1 (4-Leu) with isoindolinone fragments exhibited the strongest antiproliferative activity against HepG-2 cell line with an IC50 of 9.54 μg/mL. The effect of compound 1 on mitochondrial membrane potential and intracellular Ca2+ concentration have been studied to evaluate the antitumor potential. The decrease of mitochondrial membrane potential and the increase of intracellular Ca2+ concentration indicated compound 1 had the excellent antitumor activity. Especially for compound 1, the molecular docking suggested that 4-Leu residue and isoindolinone fragments presented stronger binding with MDM2 oncoprotein of liver cancer cells, which plays an important role in the stability of MDM2 ligands.

Photoinduced Single Electron Transfer Cyclization Reactions ofN-(Trimethylstannyl terminated substituent group)imide

合成了两种新的分子内给受电子体系N-[2-（2-三丁基锡甲硫基）乙基KB苯二甲酰亚胺（1a）和N-（3-三丁基锡丙基）马来酰亚胺（1b），并在甲醇、乙腈-30％水、乙腈中进行了光诱导单电子转移反应．化合物1a在光诱导下发生分子内单电子转移反应，以很高的产率和区域选择性生成环胺醇2．化合物1b在光诱导下发生分子内单电子转移反应生成环胺醇3，同时有[2-1-2]}环加成副反应产物4生成．以上所有新化合物的结构经质谱和核磁共振谱验证．

Atom transfer radical cyclization reactions (ATRC): synthetic applications

Atom transfer cyclization reactions (ATRC) provide rapid access to functionalized γ-butyrolactones.

Electrochemistry of copper complexes with macrocyclic polyamines containing pyrazole units

The voltammetric behaviour of bi- and mono-nuclear complexes formed in solution by Cu(2+) with three polyazacyclophanes containing pyrazole units in aqueous solution is described. Cyclic and square wave voltammetric responses at glassy carbon electrodes indicate that the reduction of copper-macrocycle complexes in solution takes place in two successive one-electron per Cu transfer processes coupled with preorganization and protonation reactions that mimic the behaviour of superoxide dismutase. The electrochemistry of ternary Cu(2+)-receptor-dopamine complexes exhibits significant differences with respect to the protection of the neurotransmitter from post-electron transfer cyclization reactions.

Dithiocarbamate Group Transfer Cyclization Reactions of Carbamoyl Radicals under “Tin‐Free” Conditions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Dithiocarbamate group transfer cyclization reactions of carbamoyl radicals under "tin-free" conditions.

Dithiocarbamate group transfer cyclization reactions of carbamoyl radicals under "tin-free" conditions.

Dithiocarbamate Group Transfer Cyclization Reactions of Carbamoyl Radicals under “Tin‐Free” Conditions

Dithiocarbamate Group Transfer Cyclization Reactions of Carbamoyl Radicals under “Tin‐Free” Conditions

On the 6-exo atom transfer radical cyclization reactions of 3-butenyl 2-iodoalkanoates.

Bis(tributyltin)-initiated atom transfer cyclization reactions of 3-butenyl iodoalkanoates in the presence of BF3.OEt2 as the catalyst afforded the 6-exo cyclization products as a mixture of 3,4-cis- and trans-substituted tetrahydro-2H-pyran-2-ones in 53-71% yield with the major isomers being the cis ones. Ab initio calculations at the B3LYP/6-31G level on the transition states of the radical cyclization and on the cyclized products revealed that the reactions are kinetically controlled and the transition states for the 6-exo radical cyclization are in boat conformations. Moreover, the cis-oriented transition states are of lower energy than the corresponding trans-oriented ones, which are in excellent agreement with experimental results.

Investigation of bis(tributyltin)-initiated free radical cyclization reactions of 4-pentenyl iodoacetates.

Bis(tributyltin)-initiated atom transfer cyclization reactions of 4-pentenyl iodoacetates (1) at 80 degrees C led to the formations of 5-(3-iodopropyl)-substituted dihydro-2(3H)-furanones (3) in high yield. With BF3*Et2O as the catalyst, the reactions were run at room temperature to afford the corresponding gamma-iodoheptanolactones (2), which could be further transformed into 3-(tetrahydro-2-furyl)propanoic acids (6) upon treatment with aqueous NaHCO3. The reaction mechanism was postulated to be the 8-endo free radical cyclization to generate gamma-iodoheptanolactones which easily underwent intramolecular nucleophilic substitution to form bicyclic acylium species (7) as the key intermediate. Subsequent attack by iodide ion furnished gamma-lactones while attack by hydroxide ion gave the tetrahydrofuran derivatives.

ChemInform Abstract: Novel Group Transfer Cyclization Reactions of Organotellurium Compounds.

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Novel group transfer cyclization reactions of organotellurium compounds

When irradiated in the presence of hexabutylditin, readily available O-allylated and O-prop-2-ynylated 2-hydroxyalkyl aryl tellurides undergo group transfer cyclization to afford 2, 4-disubstituted tetrahydrofuran derivatives.

Effects of temperature on atom transfer cyclization reactions of allylic .alpha.-iodo esters and amides

Atom-transfer cyclizations of allyl iodoacetates and N-alyl-N-methyliodoacetamides are much more efficient at 80°C than at 25°C. At 80°C, β-(iodomethyl) lactones and lactams are formed rapidly and in good yield under standard atom-transfer conditions (sunlamp irradiation of iodide and 10% hexabutylditin in benzene for 10−60 min). It is proposed that this temperature effect is responsible for some unusual observations by Jolly and Livinghouse in the cyclization of N-cyclohexenyl-N-methyliodoacetamide. The results suggest that the beneficial effect of temperature arises because an increase in the rate of rotation of the OC−O or OC−N bond in the intermediate radicals begins to convert syn radicals (which cannot cyclize) to anti radicals (which can cyclize)

ChemInform Abstract: Atom Transfer Cyclization Reactions of Hex‐5‐ynyl Iodides: Synthetic and Mechanistic Studies.

AbstractThree useful sets of reaction conditions (portionwise or syringe pump addition of catalytic Bu3SnH and photolysis with catalytic hexabutyltin) are given for the cyclization of hex‐5‐ynyl iodides such as (I) to (iodomethylene)cyclopentanes such as (II).

Atom transfer cyclization reactions of hex-5-ynyl iodides: synthetic and mechanistic studies

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAtom transfer cyclization reactions of hex-5-ynyl iodides: synthetic and mechanistic studiesDennis P. Curran, Meng Hsin Chen, and Dooseop KimCite this: J. Am. Chem. Soc. 1989, 111, 16, 6265–6276Publication Date (Print):August 1, 1989Publication History Published online1 May 2002Published inissue 1 August 1989https://doi.org/10.1021/ja00198a043RIGHTS & PERMISSIONSArticle Views1091Altmetric-Citations118LEARN 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-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Atom transfer cyclization reactions of .alpha.-iodo esters, ketones, and malonates: examples of selective 5-exo, 6-endo, 6-exo, and 7-endo ring closures

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAtom transfer cyclization reactions of .alpha.-iodo esters, ketones, and malonates: examples of selective 5-exo, 6-endo, 6-exo, and 7-endo ring closuresDennis P. Curran and Chi Tai ChangCite this: J. Org. Chem. 1989, 54, 13, 3140–3157Publication Date (Print):June 1, 1989Publication History Published online1 May 2002Published inissue 1 June 1989https://doi.org/10.1021/jo00274a034RIGHTS & PERMISSIONSArticle Views4637Altmetric-Citations386LEARN 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 (3 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Atom transfer cyclization reactions of α-iodo carbonyls

The free radical isomerization of unsaturated α-iodo carbonyls to cyclic γ-iodo carbonyls is described. Iodine atom abstraction from the starting iodide by the cyclic radical is the key chain transfer step.