81867-37-0Relevant articles and documents
Methyl Radical Initiated Kharasch and Related Reactions
Tappin, Nicholas D. C.,Renaud, Philippe
supporting information, p. 275 - 282 (2020/12/07)
An improved procedure to run halogen atom and related chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di-tert-butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methyl radicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating greatly product purification by either flash column chromatography or distillation. In addition, remarkably simple and mild reaction conditions (refluxing EtOAc during 30 minutes under normal atmosphere) and a low excess of the radical precursor reagent (2 equivalents) make this protocol particularly attractive for preparative synthetic applications. This initiation procedure has been demonstrated with a broad scope since it works efficiently to add a range of electrophilic radicals generated from iodides, bromides, selenides and xanthates over a range of unactivated terminal alkenes. A diverse set of radical trap substrates exemplifies a broad functional group tolerance. Finally, di-tert-butyl peroxyoxalate (DTBPO) is also demonstrated as alternative source of tert-butoxyl radicals to initiate these reactions under identical conditions which gives gaseous by-products (CO2). (Figure presented.).
Direct Trifluoromethoxylation without OCF3-Carrier through In Situ Generation of Fluorophosgene
Donnard, Morgan,Guérin, Thomas,Hanquet, Gilles,Leroux, Frédéric R.,Panossian, Armen,Saiter, Jérémy
supporting information, p. 3139 - 3147 (2021/06/26)
Owing to the high interest in the OCF3 group for pharmaceutical and agrochemical applications, trifluoromethoxylation received great attention in the last years with several new methods for this approach towards OCF3-comprising compounds. Yet, it most often requires the beforehand preparation of specific F3CO? transfer reagents, which can be toxic, expensive, unstable, and/or generate undesired side-products upon consumption. To circumvent this, the in-situ generation of gaseous fluorophosgene from triphosgene, its conversion by fluoride into the OCF3 anion, and the direct use of the latter in nucleophilic substitutions is an appealing strategy, which, although recently approached, has not been fully exploited. We disclose herein our efforts towards this aim.
COATING FOR METAL NANOPARTICLES
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Paragraph 000153, (2017/08/01)
The invention relates to a ligand compound having a structure A-B-C, wherein (a) A represents a mono- or polyphosphorylated amino acid linked to part B by its amino group to form an amide bond; B represents (i) a carboxylic acid, and (ii) an amino acid or peptidyl group of 2-10 amino acids, an alkyl or alkenyl group comprising 1 -26 carbon atoms, a polyethylene glycol group comprising 1 -26 carbon atoms or a combination thereof covalently linked to the carboxylic acid; and C represents a hydrophilic group covalently linked to the group of B (ii) or (b) A represents a mono-or polyphosphorylated amino acid linked to B by its carboxylic acid to form an amide bond; B represents an amino acid or peptidyl group of 2-10 amino acids, an amino substituted alkyl or alkenyl group comprising 1 -26 carbon atoms, an amino substituted polyethylene glycol group comprising 1 -26 carbon atoms or a combination thereof covalently linked to A by their amino group; C represents a hydrophilic group covalently linked to the group of B. The invention further relates to a coated metal nanoparticle such as super paramagnetic iron oxide nanoparticle (SPIONs) coated with a plurality of the aforementioned ligands and a method of producing thereof.
Tuning the interactions between electron spins in fullerene-based triad systems
Lebedeva, Maria A.,Chamberlain, Thomas W.,Davies, E. Stephen,Thomas, Bradley E.,Schroeder, Martin,Khlobystov, Andrei N.
, p. 332 - 343 (2014/03/21)
A series of six fullerene-linker-fullerene triads have been prepared by the stepwise addition of the fullerene cages to bridging moieties thus allowing the systematic variation of fullerene cage (C60 or C70) and linker (oxalate, acetate or terephthalate) and enabling precise control over the inter-fullerene separation. The fullerene triads exhibit good solubility in common organic solvents, have linear geometries and are diastereomerically pure. Cyclic voltammetric measurements demonstrate the excellent electron accepting capacity of all triads, with up to 6 electrons taken up per molecule in the potential range between -2.3 and 0.2 V (vs Fc+/Fc). No significant electronic interactions between fullerene cages are observed in the ground state indicating that the individual properties of each C60 or C 70 cage are retained within the triads. The electron-electron interactions in the electrochemically generated dianions of these triads, with one electron per fullerene cage were studied by EPR spectroscopy. The nature of electron-electron coupling observed at 77 K can be described as an equilibrium between doublet and triplet state biradicals which depends on the inter-fullerene spacing. The shorter oxalate-bridged triads exhibit stronger spin-spin coupling with triplet character, while in the longer terephthalate-bridged triads the intramolecular spin-spin coupling is significantly reduced.
Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 15. Generation of alkoxycarbonyl(sulfenyl)carbenes and their intramolecular insertion to give alkenyl sulfides
Aitken, R. Alan,Armstrong, Jill M.,Drysdale, Martin J.,Ross, Fiona C.,Ryan, Bruce M.
, p. 593 - 604 (2007/10/03)
A range of 18 alkoxycarbonyl sulfinyl phosphorus ylides 9 have been prepared and their behaviour upon flash vacuum pyrolysis (FVP) at 600 deg C examined. For R1 = H, Me and Et they lose Ph3PO and in some cases Ph3P to give mixtures of products including the alkenyl sulfides 10, the sulfides 11, the disulfides 12 and the thioesters 14. The alkenyl sulfides 10 most likely arise from intramolecular insertion of the alkoxycarbonyl sulfenyl carbenes resulting from loss off Ph3PO to produce β-lactones which then lose CO2 and this is supported by the results from 13C labelled ylides. Possible mechanisms for the formation of 11 and 14 are also presented and the feasibility of various steps has been examined by preparation and pyrolysis of the proposed intermediates. In contrast, pyrolysis of the ylides 9 where R1 = Ph and the tert-butoxycarbonyl ylides 30 leads mainly to complete fragmentation with loss of Ph3PO and benzyl alcohol or 2-methylpropan-2-ol and does not give any useful sulfur-containing products. Four alkoxy-carbonyl sulfonyl diazo compounds 33 have been prepared and in three cases they give the alkenyl sulfones 34 upon FVP at 400 deg C, probably by an intramolecular insertion and decarboxylation process analogous to the formation of 10 from 9. On the other hand the alkoxycarbonyl carbenes produced by FVP of the amino acid-derived diazo compounds 35 undergo alternative proocesses with no sign of β-lactone formation. Fully assigned 13C NMR data are presented for 13 of the ylides.
32-Ascomycinyloxyacetic acid derived immunosuppressants. Independence of immunophilin binding and immunosuppressive potency
Wagner, Rolf,Rhoades, Teresa A.,Or, Yat Sun,Lane, Benjamin C.,Hsieh, Gin,Mollison, Karl W.,Luly, Jay R.
, p. 1764 - 1776 (2007/10/03)
The potent immunosuppressant ascomycin (1b) was selectively alkylated at the C-32 carbinol, thus providing esters and amides of 32- ascomycinyloxyacetic acid (4, AOAA). These compounds present structural variation at the FKBP/calcineurin interface. While the native carboxylic acid 4 shows no activity in vitro, esters and simple amides of 4 exhibit potent immunosuppression in the human MLR assay. Moreover, amides show inhibitory activity in the rat popliteal lymph node hyperplasia assay. Surprisingly, FKBP binding was weakened by several orders of magnitude when secondary hydrophobic aryl amides of 4 were tested, while maintaining potent immunosuppressive efficacy in vitro.
Acridinium compounds as chemiluminogenic label
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, (2008/06/13)
New acridinium compounds are provided which comply with formula 1, wherein A is a divalent organic moiety, such as an alkylene chain, X is a group which can be transformed together with C-9 of the acridine into a dioxetane by reaction with hydrogen peroxide, such as an aryloxy group, Y is a counter ion, and Z is a functional group, such as a carboxyl derivative. These acridinium compounds are useful as chemiluminogenic labels for both heterogeneous and homogeneous immunoassays.
