Cleavage Of Carbon-carbon Double Bond Research Articles

O-Alkynylaryl 2-Cyanoacrylates: A Synthon for the Construction of Diverse Isoquinolones/Napthyridinones.

o-Alkynylaryl 2-cyanoacrylates have been disclosed as a new synthon for the regioselective synthesis of isoquinolones and naphthyridinones under mild reaction conditions. The attractive feature of this investigation includes carbon-carbon double bond cleavage under metal-free conditions by an intramolecular SN2 reaction. Incorporating two distinct C-I bonds in the resulting products provides facile opportunity for structural elaboration. The viability of the present protocol was unveiled by postfunctionalization with drug analogues and gram-scale synthesis.

Visible Light-Induced Carboxylation of Alkenes via Cleavage of Carbon-Carbon Double Bond

Visible Light-Induced Carboxylation of Alkenes via Cleavage of Carbon-Carbon Double Bond

Highly selective turn-on fluorescent probe for hypochlorite and viscosity detection

Due to the important role of hypochlorous acid (HOCl) in immune prevention of bacteria towards living organisms and its variations may be related to the change of intracellular viscosity, it is significant to design fluorescent probe to accurately analyze changes for detecting HOCl and viscosity simultaneously. In this paper, water-soluble, very fast-responsive fluorescent probes PTZ-TPP and PTZ-MP based on phenothiazine moiety were developed. The sensing mechanism of the probe with HOCl was elucidated by emission spectra at long and short excited wavelength 480 and 380 nm, and the oxidation structure OPTZ-TPP, sulfur peroxide structure O3PTZ-TPP as well as carbon-carbon double bond cleavage structure OCy-TPP were confirmed by ESI-MS analysis. The detection limit (LOD) of probe PTZ-TPP and PTZ-MP was evaluated to be 14.7 and 19.4 nM respectively. Moreover, the probe PTZ-MP was further used for the detection of viscosity. Furthermore, cell imaging of PTZ-TPP towards HOCl was conducted. And it is expected to be used in simultaneous determination of HOCl and viscosity in intracellular.

The catalytic cleavage of carbon-carbon double bond in polychloroprene induced by Schwartz's reagent via chlorine self-assisted β-alkyl elimination mechanism

The carbon-carbon double bonds (CC) in polychloroprene (PCP) was broken down by Schwartz's reagent ([Cp2ZrClH]n) under mild conditions. The reaction mechanism for cleaving CC bonds in PCP was studied in detail. It was found that the cleavage pathway was chlorine self-assisted β-alkyl elimination reaction, namely, β-alkyl elimination was promoted while chlorine in PCP was eliminated by releasing Cp2ZrCl2. The molecular weights of chain-scission products were controlled ranging from starting molecular weights of PCP to 0.2 kg mol−1; at the same time, microstructures of chain-scission products were similar to chain structures of original PCP. In addition, chain-scission products could be chain-end functionalized by electrophiles quenching chain scission reaction. More importantly, efficient catalytic chain cleavage was achieved under the synergistic effect of [Cp2ZrClH]n with both LiH and H2.

A reaction based one- and two-photon fluorescent probe for selective imaging H2O2 in living cells and tissues

Hydrogen peroxide (H2O2) exists extensively in mammalian cells as an active and significant by-products in bio-metabolism and plays vital roles in normal physiological activities and the occurrence of many diseases. Thus, development of fluorescence probes for monitoring H2O2 is profound for the diagnosis and treatment of these diseases. Other than previous reported fluorescence probes for H2O2, we proposed a two-photon fluorescence probe GC-2 possessing an original response enamine group, which can undergo the cleavage of carbon-carbon double bond by H2O2 and result in the appearance of blue fluorescence due to Intramolecular Electron Transfer (ICT). The probe GC-2 exhibited satisfactory sensitivity to H2O2 with the limitation of detection (LOD) of 2.1×10−7M, and displayed good selectivity to H2O2 from other ROS and amine acids under physiological pH conditions. Remarkably, our probe GC-2 showed admirable one- and two- photon fluorescence imaging capability in living cells and tissues with low cytotoxicity. In a word, the rational designed probe has tremendous potential for monitoring H2O2 in living systems utilizing the one- and two- photon fluorescence imaging.

Carotenoid Cleavage Oxygenases from Microbes and Photosynthetic Organisms: Features and Functions.

Apocarotenoids are carotenoid-derived compounds widespread in all major taxonomic groups, where they play important roles in different physiological processes. In addition, apocarotenoids include compounds with high economic value in food and cosmetics industries. Apocarotenoid biosynthesis starts with the action of carotenoid cleavage dioxygenases (CCDs), a family of non-heme iron enzymes that catalyze the oxidative cleavage of carbon–carbon double bonds in carotenoid backbones through a similar molecular mechanism, generating aldehyde or ketone groups in the cleaving ends. From the identification of the first CCD enzyme in plants, an increasing number of CCDs have been identified in many other species, including microorganisms, proving to be a ubiquitously distributed and evolutionarily conserved enzymatic family. This review focuses on CCDs from plants, algae, fungi, and bacteria, describing recent progress in their functions and regulatory mechanisms in relation to the different roles played by the apocarotenoids in these organisms.

Oxidation of Cyclohexanediol Derivatives with 12-Tungstophosphoric Acid-Hydrogen Peroxide System

Oxidation of cyclohexanediol derivatives with 12-tungstophospholic acid-hydrogen peroxide system was investigated focusing on a reaction mechanism in the preparation of dicarboxylic acids from olefin because oxidative cleavage of vicinal diols would be a rate-determining step in oxidative cleavage of carbon-carbon double bonds. trans-1,2-Cyclohexanediol (DHC) was converted to adipic acid almost quantatively, while 1-hydroxy-2-methoxycyclohexane (HMC) gave a mixture of adipic acid, glutaric acid and monomethyl adipate. In the case of 1,4-cyclohexanediol, 4-hydroxy-cyclohexanone and many hyperoxidated products were obtained. Based on results for HMC, it is concluded that following route would be also reasonable in oxidative cleavage of vicinal diol with 12-tungstophospholic acid-hydrogen peroxide system: (1) first oxidation of vicinal diol to alpha-hydroxyketone, (2) nucleophilic attack of hydrogen peroxide attacks to carbonyl carbon, (3) Baiyer-Villiger rearrangement of dihydroxy-hydroperoxide to a cyclic ester, (4) hydrolysis and final oxidation to dicarboxylic acid.

Clay-supported ceric ammonium nitrate as an effective, viable catalyst in the oxidation of olefins, chalcones and sulfides by molecular oxygen

A highly efficient and selective carbon-carbon double bond cleavage of olefins, chalcones and also oxidation of sulfides involving molecular oxygen is achieved using K10-montmorillonite clay-supported ceric ammonium nitrate (CAN) in methanol medium. The catalyst is recycled without any loss in activity and selectivity. A suitable mechanism wherein all the three species are assembled within the clay interlayer is proposed.

Oxidative Cleavage with Hydrogen Peroxide: Preparation of Polycarboxylic Acids from Cyclic Olefins

Oxidative cleavage of carbon-carbon double bonds of cyclic olefins with hydrogen peroxide in the presence of heteropolyacids has been investigated as a clean and environmentally friendly preparation of polycarboxylic acids. In the presence of 12-tungstophospholic acid (H(3)PW(12)O(40)), adipic acid was obtained in 95% yield from cyclohexene in lipophilic phase and hydrogen peroxide in aqueous phase. In addition, 1,2,3,4-butanetetracarboxylic acid was also obtained in 87% yield from 1,2,3,6-tetrahydrophtharic acid anhydride, while endic acid anhydride did not afford corresponding 2,3,6-cyclopentanetetracarboxylic acid but only lactone compound was obtained. In this oxidation process, oxidative cleavage of carbon-carbon double bonds would proceed as the sequential reactions in which the rate determining step is oxidative cleavage of vicinal-diol compounds.

Focus on Molecules: RPE65, the visual cycle retinol isomerase

The RPE65 gene (UniProtKB/Swiss-Prot: Q16518 (RPE65_Human); OMIM: 180069; http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=180069) is localized to human chromosome 1p31 and to distal mouse chromosome 3 and is a single copy gene, except in zebrafish where there are 2 copies, a consequence of the genome duplication in the teleost ancestry. RPE65 protein is highly preferentially expressed in retinal pigment epithelium (RPE) of all vertebrates (Fig. 1A), and may be expressed at low level in cone photoreceptors of some species. All RPE65 proteins are 533 amino acid residues in length, except in zebrafish where RPE65a gene product has 531 and RPE65b gene product 532 residues, respectively. RPE65 belongs to the evolutionarily diverse carotenoid oxygenase superfamily. The basic reaction catalyzed by these enzymes is oxidative cleavage of carbon-carbon double bonds in the polyene backbone of carotenoids and related molecules. One of RPE65’s 2 mammalian relatives is βcarotene monooxygenase, which cleaves β-carotene into all-trans retinal, the first step in animal vitamin A metabolism. The crystal structure of cyanobacterial Synechocystis apocarotenal oxygenase, a carotenoid oxygenase, predicts that these proteins share a common seven-bladed propeller structure containing non-heme ferrous iron coordinated by four histidines, three of which are fixed by glutamate residues. Each blade of the propeller, consisting of 4 or 5 anti-parallel beta-sheets, contributes one part of the iron coordination apparatus (Fig. 1B). The locations of these beta sheets are conserved and these contribute to a rigid structure. Inter-strand and inter-blade loops are less conserved and are predicted to contribute to specificity of substrate binding in the different family members. RPE65 is predicted to share the overall secondary structure required to support this tertiary structure and mutagenesis studies support the requirement of the coordinating histidines in RPE65 activity (Redmond et al., 2005).

An Efficient Transformation of Cyclic Ene-carbamates into .OMEGA.-(N-Formylamino)carboxylic Acids by Ruthenium Tetroxide Oxidation

The ruthenium tetroxide (RuO(4)) oxidation of cyclic ene-carbamates resulted in the endo-cyclic carbon-carbon double bond cleavage to afford the corresponding omega-(N-formylamino)carboxylic acids in good yields. Substituted cyclic ene-carbamates derived from (3R)-3-hydroxypiperidine hydrochloride were converted into the N-Boc 4-aminobutyric acids by utilization of the RuO(4) oxidation as the key step, which were further transformed into (3R)-4-amino-3-hydroxybutyric acid, an important key intermediate for the synthesis of L-carnitine.

Carbon—Carbon Bond Cleavage Reaction and Its Application Using Transition Metals

For Abstract see ChemInform Abstract in Full Text.

遷移金属を用いた炭素−炭素結合切断とその応用

Carbon-carbon bond cleavage reactions of organic compounds using transition metal complexes are reviewed. The reactions are first classified by the bond order; (i) carbon-carbon single bond cleavage, (ii) carbon-carbon double bond cleavage, and (iii) carbon-carbon triple bond cleavage. For the carbon-carbon single bond cleavage reactions, reactions are classified by the functional groups of the organic compounds. It is shown that in many cases the β, γ-carbon-carbon bond of the organic molecules on metals tends to be cleaved formally. In the case of the carbon-carbon double bond, there are only some examples of the direct cleavage by metals such as a ketene which produces a carbonyl-carbene complex. The direct cleavage of the double bond by metals, which formally affords bis-carbene, is not favorable. In contrast, the carbon-carbon cleavage of the triple bond is achieved by the multi-metal systems which stabilize the cleaved fragments.

Influence of the solvent on the titanium beta catalyzed oxidation of phenylethylenes without carbon-carbon double bond cleavage

Phenylethylenes can be oxidized in methanol by hydrogen peroxide in the presence of zeolite beta containing titanium (Ti-β) to give predominantly glycol monomethyl ethers (arising from the acidcatalyzed opening up of the primary epoxide) accompanied by lower amounts of carbonyl compounds (derived from the oxidative C—C bond cleavage). These results contrast with those obtained using the same Ti-β catalyst in acetonitrile or acetone as solvent or with those previously reported using titanium silicalite, where C—C bond rupture was the main process.

Heterogeneous permanganate oxidations. 5. The preparation of aldehydes by oxidative cleavage of carbon-carbon double bonds

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeterogeneous permanganate oxidations. 5. The preparation of aldehydes by oxidative cleavage of carbon-carbon double bondsDonald G. Lee, Tao Chen, and Zhao WangCite this: J. Org. Chem. 1993, 58, 10, 2918–2919Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1 May 1993https://doi.org/10.1021/jo00062a046RIGHTS & PERMISSIONSArticle Views1114Altmetric-Citations42LEARN 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 (204 KB) Get e-Alerts Get e-Alerts

Carbon-carbon double bond cleavage with a hard lewis acid and ethanethiol

Double bonds activated by the electron withdrawing group(s) are cleaved with the reagent system consisting of a hard Lewis acid and ethanethiol to give dithioacetals.

Investigation of the oxidative cleavage of butyl rubber by selective catalysis

Selective oxidizing cleavage of carbon-carbon double bonds of unsaturated polymers leads to bifunctional oligomers. It is shown, using ruthenium tetroxide in catalytic amount in conjunction with a peracid as co-oxidizing agent, that efficient cleavage of butyl rubber double bonds can be obtained without side reaction. The procedure can be used for analytical as well as for synthetic purpose.

Synthesis of w-Cyanoaldehydes through Carbon-Carbon Double Bond Cleavage of Cycloolefins

Synthesis of w-Cyanoaldehydes through Carbon-Carbon Double Bond Cleavage of Cycloolefins