20135-15-3Relevant articles and documents
NOVEL BIS-INDOLIC DERIVATIVES, A PROCESS FOR PREPARING THE SAME AND THEIR USES AS A DRUG
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Paragraph 0294; 0295, (2013/03/26)
The present invention relates to novel bis-indolic derivatives, processes for their preparation, and their potential use as new antibacterial drugs.
Novel bis-indolic derivatives, their uses in particular as antibacterials
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Paragraph 0232-0233, (2013/03/26)
The present invention relates to novel bis-indolic derivatives, processes for their preparation, and their potential use as new antibacterial drugs.
BIS-INDOLIC DERIVATIVES, A PROCESS FOR PREPARING THE SAME AND THEIR USES AS A DRUG
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Page/Page column 59, (2013/03/26)
The present invention relates to novel bis-indolic derivatives, processes for their preparation, and their potential use as new antibacterial drugs.
Molybdenum oxide/bipyridine hybrid material {[MoO3(bipy)] [MoO3(H2O)]}n as catalyst for the oxidation of secondary amines to nitrones
Abrantes, Marta,Gonalves, Isabel S.,Pillinger, Martyn,Vurchio, Carolina,Cordero, Franca M.,Brandi, Alberto
experimental part, p. 7079 - 7082 (2012/01/30)
The inorganic-organic hybrid material {[MoO3(bipy)][MoO 3(H2O)]}n (bipy = 2,2′-bipyridine) can be used as a water-tolerant catalyst for the oxidation of secondary amines under mild conditions using either urea hydrogen peroxide (UHP) or tert-butylhydroperoxide (TBHP) as the oxidant. Under optimized reaction conditions (2 mol % catalyst, 3-4 equiv TBHP, CH2Cl2 as the solvent, 40 °C), the corresponding nitrones were obtained with different efficiency depending on the nature of the cyclic or acyclic amine used.
Reduction of 2,3-dihydroisoxazoles to β-amino ketones and β-amino alcohols
Aschwanden, Patrick,Kvaerno, Lisbet,Geisser, Roger W.,Kleinbeck, Florian,Carreira, Erick M.
, p. 5741 - 5742 (2007/10/03)
(Chemical Equation Presented) We report the reduction of 2,3-dihydroisoxazoles to β-amino ketones and β-amino alcohols. The latter are obtained in high diastereoselectivity with preference for the syn isomer.
Asymmetric synthesis of β-amino acids by addition of chiral enolates to nitrones via N-acyloxyiminium ions
Kawakami,Ohtake,Arakawa,Okachi,Imada,Murahashi
, p. 2423 - 2444 (2007/10/03)
N-Acyloxyiminium ions, generated by the reaction of nitrones with acyl halides, are highly reactive species and undergo facile reaction with a wide range of nucleophiles, such as ketene silyl acetals, titanium(IV) and boron enolates, hydrido- and allyltin(IV) reagents, and alkynyltitanium(IV) reagents, to give α-substituted amine derivatives. Optically active β-amino acids can be prepared by the reaction of N-acyloxyiminium ions with both boron and titanium(IV) enolates bearing chiral auxiliaries. Reversal of diastereoselectivity was observed by the reactions of the boron and titanium(IV) enolates. Using these reactions, all of the four stereoisomers of α-methyl-β-phenylalanines, for example, can be prepared highly diastereoselectively. Cyclic N-acyloxyiminium ions are useful for the asymmetric synthesis of pyrrolidine and piperidine alkaloids; (5R,8R,8aS)-5-cyano-8-methylindolizidine, which is a common key intermediate for synthesis of 5-substituted 8-methylindolizidines, was prepared selectively.
Regiochemistry and mechanism of oxidation of N-benzyl-N-alkylhydroxylamines to nitrones
Hassan, Azfar,Wazeer, Mohammed I. M.,Saeed, Mohammed T.,Siddiqui, Mohammad N.,Ali, Sk. Asrof
, p. 443 - 451 (2007/10/03)
The oxidation of various N-(o-, m-, p-substituted benzyl)-N-alkylhydroxylamines and their dideuteriobenzyl (PhCD2) counterparts was carried out using mercury(II) oxide and p-benzoquinone (p-BQ) as oxidants. An overwhelming preference for the formation of conjugated nitrones is observed in the oxidation of N-benzyl-N-isopropylhydroxylamines. Considerable intra- and intermolecular kinetic isotope effects and negative ρ values in the Hammet plots point towards a mechanistic pathway that involves electron transfer from nitrogen to the oxidant followed by hydrogen abstraction. The conformation of unstable (E)-nitrones, which readily isomerize to the more stable (Z)-nitrones, is deduced from 1H NMR data. The E ? Z isomerization was found to be a bimolecular process. Copyright
Regioselective synthesis of nitrones by decarboxylative oxidation of N- alkyl-α-amino acids and application to the synthesis of 1-azabicyclic alkaloids
Ohtake, Hiroaki,Imada, Yasushi,Murahashi, Shun-Ichi
, p. 2737 - 2754 (2007/10/03)
Tungstate-catalyzed oxidation of N-alkyl-2a-amino acids with 30% H2O2 solution under phase-transfer conditions gives nitrones regioselectively in good yields: Using this method, stereodivergent synthesis of (R)- and (S)-4- (t-butyldimethylsilyloxy)-1-pyrroline N-oxides ((R)-17a and (S)-17a) was achieved. In addition, (R)- and (S)-3-(t-butyldimethylsilyloxy)-1-pyrroline N-oxides ((R)-45 and (S)-45) were prepared by catalytic oxidation of the corresponding chiral pyrrolidines in a regioselective manner. These chiral cyclic nitrones, 17 and 45 are versatile intermediates for the synthesis of optically active nitrogen heterocycles, since stereoselective additions of carbon nucleophiles to these chiral nitrones can be readily performed. Typically, ZnI2-mediated addition of ketene t-butyldimethylsilyi methyl acetal (29a): to (R)-17a gave the' cis-adduct, methyl (2R,4R)-[1,4-bis(t- butyldimethylsilyloxy)pyrrolidin-2-yl]acetate (cis-30). In contrast, the addition of lithium acetylides 34 to the nitrone (R)-17a gave the trans- adducts, (2S,4R)-2-(1-alkynyl)-4-(t-butyldimethylsilyloxy)-1- hydroxypyrrolidines trans-35. These adducts are useful intermediates for syntheses of the nitrogen heterocycles (3R,5R)-1-aza-3- hydroxybicyclo[3.3.0]octane (37) and (6R,8R)-1-aza-8- hydroxybicyclo[4.30]nonane (38), respectively. The ZnI2-mediated addition of ketene silyl acetal 29a to the nitrone (R)-45 gave methyl (2S, 3R)-[1,3- bis(t-butyldimethylsilyloxy)pyrrolidin-2-yl]acetate (trans-50a), which was used for asymmetric synthesis of the Geissman-Waiss lactone ((-)-49).
Methyltrioxorhenium-Catalyzed Oxidation of Secondary and Primary Amines with Hydrogen Peroxide
Yamazaki, Shigekazu
, p. 877 - 883 (2007/10/03)
The methyltrioxorhenium-catalyzed oxidation of secondary amines and primary amines with hydrogen peroxide has been carried out. The oxidation of secondary amines afforded nitrones in good-to-excellent yield. Benzylamines were selectively oxidized to oximes, while general primary alkylamines possessing the α-C -H bond gave mixtures of oximes, nitroso dimers, and azoxy compounds.
Tungstate-Catalyzed Decarboxylative Oxidation of N-Alkyl-α-amino Acids: An Efficient Method for Regioselective Synthesis of Nitrones
Murahashi, Shun-Ichi,Imada, Yasushi,Ohtake, Hiroaki
, p. 6170 - 6172 (2007/10/02)
The tungstate-catalyzed oxidation of N-alkyl-α-amino acids with hydrogen peroxide under phase-transfer conditions gives the corresponding nitrones in satisfactory yield.
