1592-38-7Relevant articles and documents
Tritium and deuterium labelling studies of alkali metal borohydrides and their application to simple reductions
Than,Morimoto,Andres,Williams
, p. 693 - 711 (1996)
Simple and facile syntheses of highly deuterated and tritiated LiBH4, NaBH4 and KBH4 were achieved by hydrogen Isotope exchange with deuterium or tritium gas at elevated temperatures. The exchange products were characterized by boron, proton and deuterium or tritium NMR spectroscopy. The extent of isotope (2H or 3H) incorporation was calculated from the patterns of 11B NMR spectra. Several samples of tritiated NaBH4 were treated with BF3-Et2O to produce tritiated borane-THF complex, which is an electrophilic reducing agent. The utility of both the borohydride reagents and borane-THF complex in labelling reactions was confirmed by exemplary reductions leading to specifically labelled products. The extent and orientation of labelling in the reduction products was assessed by a combination of radio-HPLC analysis, 1H, 2H or 3H NMR and mass spectrometry.
Elucidation of a Sequential Iminium Ion Cascade Reaction Triggered by a Silica Gel-Promoted Aza-Peterson Reaction
Jones, Elizabeth V.,Chen, Doris,Wright, Stephen W.,Trujillo, John I.,France, Stefan
, p. 15660 - 15666 (2020)
In a recent methodological study investigating the synthesis of N-alkoxyazomethine ylides, an unexpected aminal byproduct was generated during our attempt to isolate O-benzyl-N-((trimethylsilyl)methyl)hydroxylamine. After a strategic investigation, silica
Discovery of inhibitors and substrates of brassinin hydrolase: Probing selectivity with dithiocarbamate bioisosteres
Pedras, M. Soledade C.,Minic, Zoran,Hossain, Sajjad
, p. 225 - 233 (2012)
Brassinin hydrolase (BHAb), an inducible enzyme produced by the plant pathogen Alternaria brassicicola under stress conditions, catalyzes the hydrolysis of the methyl dithiocarbamate group of the phytoalexin brassinin, to indolyl-3-methanamine, methane thiol and carbonyl sulfide. Thirty four substrate inspired compounds, bioisosteres of brassinin and a range of related compounds, were evaluated as potential substrates and inhibitors of BHAb for the first time. While six compounds containing thiocarbamate, carbamate and carbonate groups displayed inhibitory activity against BHAb, only two were found to be substrates (thionecarbamate and dithiocarbamate). Methyl naphthalen-1-yl-methyl carbamate, the most potent inhibitor of the six, and methyl N′-(1-methyl- 3-indolylmethyl)carbamate inhibited BHAb through a reversible noncompetitive mechanism (Ki = 89 ± 9 and 695 ± 60 μM, respectively). Importantly, these carbamate inhibitors were resistant to degradation by A. brassicicola. Carbonates were also inhibitory of BHAb, but a quick degradation by A. brassicicola makes their potential use as crop protectants less likely. Overall, these results indicate that indolyl and naphthalenyl carbamates are excellent lead structures to design new paldoxins that could inhibit the detoxification of brassinin by A. brassicicola.
Mechanistic Insights on Reduction of Carboxamides by Diisobutylaluminum Hydride and Sodium Hydride?Iodide Composite
Ong, Derek Yiren,Watanabe, Kohei,Takita, Ryo,Chiba, Shunsuke
, (2019)
The reaction mechanisms on reduction of tertiary carboxamides by diisobutylaluminum hydride (DIBAL) and sodium hydride (NaH)-sodium iodide (NaI) composite were elucidated by the computational and experimental approaches. Reduction of N,N-dimethyl carboxamides with DIBAL provides the corresponding amines, whereas that with the NaH?NaI composite exclusively forms aldehyde even at high reaction temperature. DFT calculations revealed that dimeric structural nature of DIBAL and Lewis acidity on its Al center play crucial role to decompose the tetrahedral anionic carbinol amine intermediate through C?O bond cleavage. On the other hand, in the reduction with the NaH?NaI composite, the resulting tetrahedral anionic carbinol amine intermediate could be kept stable, thus providing aldehydes as a sole product by the aqueous workup.
New [4]helicene derivatives: Synthesis, characterization and photophysical properties
Hafedh, Nesrine,Aloui, Faouzi,Raouafi, Sondes,Dorcet, Vincent,Hassine, Béchir Ben
, p. 310 - 316 (2018)
The design and synthesis of new [4]helicene derivatives were carried out by incorporating well-defined electron donor and acceptor groups at selected positions of the aromatic nuclei, aiming to use them in optical applications. Helicenes have been obtained in good overall yields through a five-step sequence involving mild experimental conditions and easy purification. Photophysical properties of these tetracyclic systems have been evaluated by UV–visible absorption and fluorescence spectroscopies and an emission in the visible region was observed.
Design, synthesis, and antitumor activity of new bis-aminomethylnaphthalenes
Bollini, Mariela,Casal, Juan Jose,Bruno, Ana Maria
, p. 8003 - 8010 (2008)
A new series of bis-aminomethylnaphthalenes were synthesized in satisfactory overall yield, through a simple synthetic strategy using reductive amination. The DNA binding properties of these compounds have been examined and compared to those of reference drugs using an UV spectroscopy method. The compounds were evaluated for their in vitro anticancer activity and some of them were studied in vivo. Compound 15 exhibited remarkable antitumor activity and represents a novel template for anticancer chemotherapy and can serve as a new lead compound.
Application of bis(phosphinite) pincer nickel complexes to the catalytic hydrosilylation of aldehydes
Chang, Jiarui,Fang, Fei,Tu, Chenhao,Zhang, Jie,Ma, Nana,Chen, Xuenian
, (2021)
A series of bis(phosphinite) (POCOP) pincer ligated nickel complexes, [2,6-(tBu2PO)2C6H3]NiX (X = SH, 1; SCH2Ph, 2; SPh, 3; NCS, 4; N3, 5), were used to catalyse the hydrosilylation of aldehydes. It was found that both complexes 1 and 2 are active in catalysing the hydrosilylation of aldehydes with phenylsilane and complex 1 is comparatively more active. The expected alcohols were isolated in good to excellent yields after basic hydrolysis of the resultant hydrosilylation products. However, no reaction was observed when complex 3 or 4 or 5 was used as the catalyst. The results are consistent with complexes 1 and 2 serving as catalyst precursors, which generate the corresponding nickel hydride complex [2,6-(tBu2PO)2C6H3]NiH in situ, and the nickel hydride complex is the active species that catalyses this hydrosilylation process. The in situ generation of the nickel hydride species was supported by both experimental results and DFT calculation.
Amino-polystyrene supported hexaethylene glycol-bridged ionic liquid as an efficient heterogeneous catalyst for water-mediated nucleophilic hydroxylation
Reddy, Mudumala Veeranarayana,Kang, Seok Min,Yoo, Suah,Woo, Sang Sik,Kim, Dong Wook
, p. 9435 - 9442 (2019)
We report a simple and eco-friendly method for producing an amino-polystyrene supported hexaethylene glycol-bridged ionic liquid (APS-HEGBIL) based on the copolymerization of amino-styrene with 1-vinyl imidazolium ionic liquid bearing hexaethylene glycol moieties, and its characterization by several analytical techniques. The resulting APS-HEGBIL catalyst was found to be remarkably efficient at catalyzing the selective nucleophilic hydroxylation of alkyl halides to produce the corresponding alcohols in water, which acted as a solvent and a nucleophilic hydroxide source. The catalyst was easily recycled and maintained its catalytic activity and stability after ten cycles with excellent yields. The main attributes of the catalyst were that it significantly enhanced the nucleophilicity of water during reactions and promoted the rapid conversions of polar and base-sensitive alkyl halide reactants to alcohols in excellent yields. The combination of ionic liquids and polymeric materials afforded quasi-homogeneous catalysts that were recycled by simple filtration and provided environmentally benign means for conducted catalytic procedures.
One-Shot Double Amination of Sondheimer-Wong Diynes: Synthesis of Photoluminescent Dinaphthopentalenes
Xu, Feng,Peng, Lifen,Shinohara, Kenta,Nishida, Takanori,Wakamatsu, Kan,Uejima, Motoyuki,Sato, Tohru,Tanaka, Kazuyoshi,Machida, Norihiko,Akashi, Haruo,Orita, Akihiro,Otera, Junzo
, p. 3014 - 3017 (2015)
Photoluminescent diamino-substituted dinaphthopentalenes were synthesized successfully by the treatment of in situ prepared dinaphthocyclooctadiyne with lithium amide. This reaction involves a series of transformations including the nucleophilic addition
The Asymmetric Ullmann Coupling Reaction of (S)-2,2'-Bis(1-bromo-2-naphthoyloxy)-1,1'-binaphtyl Revisited. Formation of 24-Membered Optically Pure Cyclic Dimer as Well as 12-Membered Cyclic Monomer
Miyano, Sotaro,Handa, Shigeru,Tobita, Masayuki,Hashimoto, Harukichi
, p. 235 - 238 (1986)
The copper-promoted Ullmann reaction of the title diester proceeded with high stereoselectivity to give 24-membered optically pure cyclic dimer of (S,S,S,S)-configuration as well as 12-membered monomeric cycle of (S,S)-configuration.The reaction also gave reduced, open-chain dimer enriched in (S,R,S)-diastereomer(S,S,S)-counterpart (17percent d.e.).Stereochemical course to the cyclic dimer was discussed considering the result that the intermolecular Ullmann coupling of chiral alcohol esters of 1-bromo-2-naphthoic acid poorly induced axial chirality in the joining of the two naphthyl units.
