- A General Approach to Deboronative Radical Chain Reactions with Pinacol Alkylboronic Esters
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The generation of carbon-centered radicals from air-sensitive organoboron compounds through nucleohomolytic substitution at boron is a general method to generate non-functionalized and functionalized radicals. Due to their reduced Lewis acidity, alkylboronic pinacol esters are not suitable substrates. We report their in situ conversion into alkylboronic catechol esters by boron-transesterification with a substoichiometric amount of catechol methyl borate combined with an array of radical chain processes. This simple one-pot radical-chain deboronative method enables the conversion of pinacol boronic esters into iodides, bromides, chlorides, and thioethers. The process is also suitable the formation of nitriles and allylated compounds through C?C bond formation using sulfonyl radical traps. The power of combining radical and classical boron chemistry is illustrated with a modular 5-membered ring formation using a combination of three-component coupling and protodeboronative cyclization.
- André-Joyaux, Emy,Kuzovlev, Andrey,Renaud, Philippe,Tappin, Nicholas D. C.
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p. 13859 - 13864
(2020/06/10)
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- Synthesis and biological evaluation of new quinoxaline derivatives of ICF01012 as melanoma-targeting probes
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The aim of this study was the synthesis and pharmacokinetic selection of a best melanin-targeting ligand for addressing anticancer agents to pigmented melanoma. Seven quinoxaline carboxamide derivatives were synthesized and radiolabeled with iodine-125. Biodistribution studies of compounds [ 125I]1a-g performed in melanoma-bearing mice tumor showed significant tumor uptake (range 2.43-5.68%ID/g) within 1 h after i.v. injection. Fast clearance of the radioactivity from the nontarget organs mainly via the urinary system gave high tumor-to-blood and tumor-to-muscle ratios. Given its favorable clearance and high tumor-melanoma uptake at 72 h, amide 1d was the most promising melanoma-targeting ligand in this series. Compound 1d will be used as building block for the design of new melanoma-selective drug delivery systems.
- El Aissi, Radhia,Liu, Jianrong,Besse, Sophie,Canitrot, Damien,Chavignon, Olivier,Chezal, Jean-Michel,Miot-Noirault, Elisabeth,Moreau, Emmanuel
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supporting information
p. 468 - 473
(2014/06/09)
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- PYRAZOLYL DERIVATIVES AS SYK INHIBITORS
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The present invention provides novel pyrazole derivatives of formula I which are potent inhibitors of spleen tyrosine kinase, and are useful in the treatment and prevention of diseases mediated by said enzyme, such as asthma, COPD, rheumatoid arthritis, and cancer.
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Page/Page column 134
(2014/01/09)
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- Easy and selective method for the synthesis of various mono-O- functionalized Calix[4]arenes: De-O-functionalization using TiCl4
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An efficient and selective method for the monofunctionalization of p-tert-butylcalix[4]arene is described. A mono-de-O-functionalization of disubstituted p-tert-butylcalix[4]arenes using titanium tetrachloride was developed to synthesize a series of monosubstituted p-tert-butylcalix[4]arenes with the pendant functions being ethoxycarbonylmethyloxy, 3- ethoxycarbonylpropyloxy, cyanomethyloxy, 3-cyanopropyloxy, 4-bromobutyloxy, 3-hydroxypropyloxy, propyloxy, 2-methylpropyloxy, 3-butynyloxy, and 3-cyanopropyloxy groups. The reaction mechanism of the formation of 5,11,17,23-tetra-tert-butyl-26,27,28-trihydroxy-25-(3-ethoxycarbonylpropyloxy) calix[4]arene was studied by 1H NMR and GC/mass spectroscopy monitoring. Reaction of TiCl4 with the disubstituted p-tert-butylcalix[4]arene produced the corresponding dioxocalix[4]arene titanium dichloride complex, which undergoes elimination of ethyl 4-chlorobutyrate, leading to a trioxocalix[4]arene titanium dichloride complex and to monosubstituted calix[4]arene after hydrolysis. These two complexes were also synthesized, isolated, and fully characterized.
- Bois, Joackim,Espinas, Jeff,Darbost, Ulrich,Felix, Caroline,Duchamp, Christian,Bouchu, Denis,Taoufik, Mostafa,Bonnamour, Isabelle
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experimental part
p. 7550 - 7558
(2011/02/25)
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- Novel annelation methodology for the rapid and efficient construction of bicyclo [4.n.0] alkanols and alkenones
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The efficient assembly of a range of fused bicyclic alcohols and enones can be readily performed using a novel, orthoester-based, annelation methodology.
- Markó, István E.,Ates, Ali
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p. 1033 - 1036
(2007/10/03)
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- Process for the production of gamma-butyrobetaine
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Process, which is feasible on a commercial scale, for the production of gamma-butyrobetaine. For this purpose, butyrolactone with hydrogen chloride and an alcohol is converted to the chlorobutyric acid ester, the trimethylammonium butyric acid salt is formed with trimethylamine and then saponified to the end product.
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- Process for the production of even series ω-amino acids
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The invention relates to a process for the production of even-series ω-amino acids of the general empirical formula NH2 (CH2 CH2)n CH2 COOH /I/, where N = 1 or 2. The process of the invention comprises telomerizing ethylene with methyl esters of halogen acetic acids of the general empirical formula Xm CH3-m COOCH3 /II/, where X = Br and m = 1 or X = Cl and m = 2 or 3, at a temperature of from 100 to 145° C. and under ethylene pressure of from 25 to 40 gage atmospheres in the presence of initiators of free-radical reactions. The telomerization procedure gives telomers of the general empirical formula CH3 OOCCH3-m Xm-1 (CH2 CH2)n X /III/, where X, n and m are as in formulas /I/ and /II/. In case X = Br and m = 1, the telomers described by formula /III/ are subjected to ammonolysis with ammonia at a temperature of about 100° C to yield ammonolysis products; whereas, in case X = Cl and m = 2 or 3, the telomers described by formula /III/ are reduced to telomers of the same general formula, where X = Cl and m = 1, and the latter are subjected to ammonolysis with ammonia at a temperature from 135° to 140° C to yield ammonolysis products. Then the ammonolysis products are hydrolyzed with hydrochloric acid at a temperature of from 80° to 90° C., and the desired product is recovered from the resultant hydrolyzate by use of a styrene-divinylbenzene sulfocationite resin in the H form. The foregoing process uses widely available industrial raw materials, proceeds by a straightforward route and requires simple equipment; it is further characterized by high yields at all steps; all unreacted feedstocks can be completely recycled; and no non-utilizable wastes are produced.
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