5745-75-5Relevant academic research and scientific papers
Allylic C-H acetoxylation with a 4,5-diazafluorenone-ligated palladium catalyst: A ligand-based strategy to achieve aerobic catalytic turnover
Campbell, Alison N.,White, Paul B.,Guzei, Ilia A.,Stahl, Shannon S.
supporting information; experimental part, p. 15116 - 15119 (2011/01/06)
Pd-catalyzed C-H oxidation reactions often require the use of oxidants other than O2. Here we demonstrate a ligand-based strategy to replace benzoquinone with O2 as the stoichiometric oxidant in Pd-catalyzed allylic C-H acetoxylation. Use of 4,5-diazafluorenone (1) as an ancillary ligand for Pd(OAc)2 enables terminal alkenes to be converted to linear allylic acetoxylation products in good yields and selectivity under 1 atm O 2. Mechanistic studies have revealed that 1 facilitates C-O reductive elimination from a π-allyl-PdII intermediate, thereby eliminating the requirement for benzoquinone in this key catalytic step.
αvβ3 integrin-targeting Arg-Gly-Asp (RGD) peptidomimetics containing oligoethylene glycol (OEG) spacers
Rerat, Vincent,Dive, Georges,Cordi, Alex A.,Tucker, Gordon C.,Bareille, Reine,Amédée, Jo?lle,Bordenave, Laurence,Marchand-Brynaert, Jacqueline
supporting information; experimental part, p. 7029 - 7043 (2010/07/05)
RGD peptides are used in biomaterials science for surface modifications with a view to elicit selective cellular responses. Our objective is to replace peptides by small peptidomimetics acting similarly. We designed novel molecules targeting αvβ3 integrin and featuring spacer-arms (for surface grafting), which do not disturb the biological activity, from (L) N-(3-(trifluoromethyl)benzenesulfonyl) tyrosine used as scaffold. Various Arg-mimics were fixed on the phenol function, and the ortho position was used for the coupling of OEG spacers. All peptidomimetics were active in the nM range in a binding test toward human αvβ 3 integrin (IC50 = 0.1 to 1.7 nM) and selective versus platelet integrin αIIbβ3. Selected compounds revealed excellent ability to inhibit bone cells adhesion on vitronectin. Modeling and docking studies were performed for comparing the most active RGD peptidomimetic to cilengitide, i.e., cyclo-[RGDfN(Me)V]-. Lastly, the adhesion of endothelial cells on a cultivation support grafted with RGD peptidomimetics was significantly improved. 2009 American Chemical Society.
STEROID ANALOGUES FOR NEUROPROTECTION
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Page/Page column 132, (2009/10/21)
Provided are steroid analogues functionalized with polar substituents at the C3 and/or C20 positions of the steroid ring system that exhibit improved water solubility. Also provided are pharmaceutical compositions comprising the steroid analogues and methods using the novel steroid analogues for the treatment and prevention of neurodegeneration in a patient following injury to the central nervous system.
Stereoselective synthesis of the monomeric unit of SCH 351448
Backes, J. Rene,Koert, Ulrich
, p. 2777 - 2785 (2007/10/03)
The monomeric unit of the macrodiolide SCH 351448 has been synthesized from three building blocks. Strategic disconnections were chosen between C21-C22 (Wittig) and C10-C11 (stereoselective aldol). The cis configuration of both 2,6-disubstituted tetrahydropyran rings was established by a stereoselective cationic reduction. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
The DDQ mediated cyclization products of some 2-hydroxy-3(1′-alkenyl)-1,4-naphthoquinones
Ameer, Farouk,Giles, Robin G.F.,Green, Ivan R.,Nagabhushana, Kyatanahalli S.
, p. 369 - 380 (2007/10/03)
The DDQ mediated cyclisation products derived from 2-hydroxy-3-(1′-alkenyl)-1,4-napthoquinones viz. 17 were found to be temperature dependent. At 60°C the naphthofuranquinone 19 was the predominant isomer whereas at 8°C the naphthopyranquinone 18 was exclusively formed.
The First Tandem [2 + 2] Cycloaddition-Michael Reaction Using Ynolates: Facile Construction of Substituted Carbocycles
Shindo, Mitsuru,Matsumoto, Kenji,Sato, Yusuke,Shishido, Kozo
, p. 2029 - 2030 (2007/10/03)
(matrix presented) A tandem [2 + 2] cycloaddition-Michael reaction using ynolate anions followed by decarboxylation produced polysubstituted five-, six-, and seven-membered cycloalkenes.
Potentiation of cADPR-induced Ca2+-release by methylxanthine analogues
Cavallaro, Rosaria A.,Filocamo, Luigi,Galuppi, Annamaria,Galione, Antony,Brufani, Mario,Genazzani, Armando A.
, p. 2527 - 2534 (2007/10/03)
Caffeine and other methylxanthines are known to induce Ca2+-release from intracellular stores via the ryanodine receptor. In the present work, a range of caffeine analogues, in which methyl groups at the 1 and 7 positions were replaced with alkyl chains containing different functional groups (oxo, hydroxyl, propargyl, ester, and acids), were synthesized. These compounds were then screened for their ability to potentiate Ca2+-release induced by cADPR (an endogenous modulator of ryanodine receptors) in sea urchin egg homogenates. Two of the synthesized methylxanthines, 1,3-dimethyl-7-(7- hydroxyoctyl)xanthine (37) and 3-methyl-7-(7-oxooctyl)-1-propargylxanthine (66), were shown to be more potent than caffeine in potentiating cADPR- induced Ca2+-release, while 1,3-dimethyl-7-(5-ethylcarboxypentyl)xanthine (14) was shown to be more efficacious. The development of new methylxanthine analogues may lead to a better understanding of ryanodine receptor function and could possibly provide novel therapeutic agents.
Catalytic asymmetric intramolecular cyclopropanation of enol silyl ether. Synthesis of the phorbol CD-ring skeleton
Tokunoh, Ryosuke,Tomiyama, Hiroshi,Sodeoka, Mikiko,Shibasaki, Masakatsu
, p. 2449 - 2452 (2007/10/03)
The optically active phorbol CD-ring skeleton was constructed using the catalytic asymmetric intramolecular cyclopropanation of enol silyl ether as a key step. Up to 92% ee was achieved using a newly modified bisoxazoline ligand.
Two convenient syntheses of brevicomin
Dandge, Chitra N,Naik, D G,Kapadi, A H
, p. 617 - 619 (2007/10/02)
Synthesis of brevicomin, 7-ethyl-7-methyl-6,8-dioxabicyclooctane (1), the aggregation pheromone of Western pine beetle, Dendroctonus brevicomis, by simple routes is described.
Synthesis of ent-Cholesterol, the Unnatural Enantiomer
Rychnovsky, Scott D.,Mickus, Daniel E.
, p. 2732 - 2736 (2007/10/02)
Cholesterol is ubiquitious in mammals and plays an important role in human health.The unique relationship between enantiomers make ent-cholesterol, the unnatural enantiomer of cholesterol, a valuable new probe of cholesterol function in biochemical systems.We report the first enantioselective total synthesis of ent-cholesterol.
