24423-88-9Relevant articles and documents
New conformationally locked bicyclic N,O-nucleoside analogues of antiviral drugs
Procopio, Antonio,Alcaro, Stefano,De Nino, Antonio,Maiuolo, Loredana,Ortuso, Francesco,Sindona, Giovanni
, p. 545 - 550 (2005)
In order to obtain rigidity within the sugar moiety of nucleosides, the bicyclic pyrimidine derivatives of N,O-isoxazolidines were designed and synthesized by using 1,3-dipolar cycloaddition of Δ1- pyrrolidine-1-oxide and the appropriate vinyl-nucleobases.
A DFT-based exploration augmented by X-ray and NMR of the stereoselectivity in the 1,3-dipolar cycloaddition of 1-pyrroline-1-oxide to methyl cinnamate and benzylidene acetophenone
Acharjee, Nivedita,Das, Tapas Kumar,Banerji, Avijit,Banerjee, Manas,Prange, Theirry
, p. 1187 - 1195 (2010)
A B3LYP/6-31G* study was carried out for the reactions of 1-pyrroline-1-oxide (N1) with methyl cinnamate (E1) and benzylidene acetophenone (E2) for getting a quantitative rationalization of the experimental findings. The product ratios were determined by NMR studies of the crude reaction mixtures. The conformation and stereochemistry of the isolated cycloadducts were finally confirmed by 2D NMR and X-ray diffraction. The endo/exo-selectivities were predicted through the computation of activation parameters on the basis of assumed concerted mechanism. The regioselectivity and reactivity were amply predicted by local and global electrophilicity indices and were found to be in good agreement with the experimental findings which were supportive of polar character and of the direction of charge transfer (CT) accompanying the cycloaddition. It was found that the cycloaddition involving methyl cinnamate was endo-selective, while that with benzylidene acetophenone produced the exo-isomer as the major adduct. Copyright
PHOTOSENSITIZED SINGLE ELECTRON TRANSFER OXIDATION OF N-HYDROXYLAMINES: A CONVENIENT SYNTHESIS OF CYCLIC NITRONES
Pandey, G.,Kumaraswamy, G.,Krishna, A.
, p. 2649 - 2652 (1987)
Photolysis of N-hydroxylamines of type 1 in the presence of 1,4-dicyanonaphthalene (DCN) as an electron acceptor gave high yields of nitrones 2.Crude nitrones have been trapped by 1,3-dipolar cycloaddition reaction with dimethyl fumarate.Mechanistic pathways have also been discussed.
Total Synthesis of the Marine Natural Product Hemiasterlin by Organocatalyzed α-Hydrazination
Lang, Jan Hendrik,Jones, Peter G.,Lindel, Thomas
, p. 12714 - 12717 (2017)
An efficient synthesis of the potently cytotoxic marine peptide hemiasterlin is presented. The tetramethyltryptophan moiety is assembled by tert-prenylation of indole, followed by the high-yielding organocatalyzed α-hydrazination of a sterically congested aldehyde with excellent enantioselectivity. 2-Bromo-N-ethylpyridinium tetrafluoroborate (BEP)-mediated peptide coupling completes the synthesis, being the first approach that does not employ chiral auxiliaries. A novel phenonium-type rearrangement of the indole system occurred when subjecting dihydroxylated 3-tert-prenylindole to Mitsunobu conditions.
A 'waterproof' catalyst for the oxidation of secondary amines to nitrones with alkyl hydroperoxides
Forcato, Massimiliano,Nugent, William A.,Licini, Giulia
, p. 49 - 52 (2003)
Catalytic oxidation of secondary amines to nitrones using alkyl hydroperoxides as primary oxidant has been demonstrated for the first time. The titanium alkoxide catalyst is protected from co-product water by the combined use of a tightly binding trialkanolamine ligand and molecular sieves. Nitrones can be obtained in high yield (up to 98%) under homogeneous, anhydrous conditions and even in the absence of solvent. The reactions are fast (2-7 h) and good selectivity can be achieved with as little as 1% catalyst.
Oxidation of N,N-disubstituted hydroxylamines to nitrones with hydrogen peroxide catalyzed by polymer-supported methylrhenium trioxide systems
Saladino, Raffaele,Neri, Veronica,Cardona, Francesca,Goti, Andrea
, p. 639 - 647 (2004)
Poly(4-vinylpyridine)/methylrhenium trioxide (MTO) compounds I-III and microencapsulated polystyrene/MTO systems IV-V are efficient catalysts for the oxidation of secondary hydroxylamines to the corresponding nitrones with H 2O2. Com
Tungstate Catalysed Oxidation of Secondary Amines with Hydrogen Peroxide. A Novel Transformation of Secondary Amines into Nitrones
Mitsui, Hitoshi,Zenki, Sei-ichi,Shiota, Tatsuki,Murahashi, Shun-Ichi
, p. 874 - 875 (1984)
The sodium tungstate catalysed oxidation of secondary amines with hydrogen peroxide gives the corresponding nitrones, which are versatile synthetic intermediates and spin trapping reagents, in a single step.
BPh3-Catalyzed [2+3] Cycloaddition of Ph3PCCO with Aldonitrones: Access to 5-Isoxazolidinones with Exocyclic Phosphonium Ylide Moieties
Brar, Amandeep,Unruh, Daniel K.,Ling, Natalie,Krempner, Clemens
, p. 6305 - 6309 (2019/08/20)
A method for the generation of 5-isoxazolidinones with exocyclic phosphonium ylide functionalities via [2+3] cycloaddition of Ph3PCCO and aldonitrones has been developed and applied in the synthesis of 4-alkylidene-5-isoxazolidinones via Wittig olefination. The reaction proceeds by BPh3 catalysis under mild conditions and with a broad substrate scope. A reaction pathway involving the activation of the aldonitrone via interactions with the Lewis acid BPh3 is proposed.
SiCl4-catalyzed/PR3-mediated β-C(sp3)?H functionalization of nitrones to α,β-unsaturated imines and aromatic heterocycles
Zhu, De-Ping,Xu, Bao-Hua,Du, Yi-Ran,Zhang, Suo-Jiang
supporting information, p. 2230 - 2238 (2018/03/29)
A novel method of SiCl4-catalyzed/PR3-mediated β-C(sp3)?H functionalization of nitrones with aldehydes/ketones to α,β-unsaturated imines was developed. The synthesis of α,β-unsaturated imines mainly invovles deoxygenation and aldol condensation, each proceeding under a cooperation effect between Lewis acid and Lewis base. In addition, both the acidity and hydrolytic stability of the weak SiCl4 were supposed to be enhanced by coordination with phosphine oxide (R = Et) or phosphoric triamide (R = NMe2) that originated from deoxygenation of nitrones by PR3. In the case of 6-membered nitrone, a [1,3]-hydride shift within the resulted α,β-unsaturated imines renders the aromatization leading to 3,5-dialkylpyridines.
Direct and Co-catalytic Oxidation of Hydroxylamines to Nitrones Promoted by Rhodium Nanoparticles Supported on Carbon Nanotubes
Prakash, Praveen,Gravel, Edmond,Nguyen, Dinh-Vu,Namboothiri, Irishi N. N.,Doris, Eric
, p. 2091 - 2094 (2017/06/27)
Rhodium nanoparticles were assembled on carbon nanotubes, and the resulting nanohybrid was studied in the aerobic oxidation of hydroxylamines to nitrones. Two catalytic systems were developed (i.e., direct or co-catalytic) and both operated to provide high yields of the products, under mild conditions, but with their own specificity as regards the kinetics and regioselectivity of the transformation. In addition, the in situ cycloaddition of the produced nitrones with different alkynes was investigated.