149182-41-2Relevant academic research and scientific papers
Phosphorus-Based Organocatalysis for the Dehydrative Cyclization of N-(2-Hydroxyethyl)amides into 2-Oxazolines
Soleymani Movahed, Farzaneh,Foo, Siong Wan,Mori, Shogo,Ogawa, Saeko,Saito, Susumu
, p. 243 - 257 (2021/12/17)
A metal-free, biomimetic catalytic protocol for the cyclization of N-(2-hydroxyethyl)amides to the corresponding 2-oxazolines (4,5-dihydrooxazoles), promoted by the 1,3,5,2,4,6-triazatriphosphorine (TAP)-derived organocatalyst tris(o-phenylenedioxy)cyclotriphosphazene (TAP-1) has been developed. This approach requires less precatalyst compared to the reported relevant systems, with respect to the phosphorus atom (the maximum turnover number (TON) ～30), and exhibits a broader substrate scope and higher functional-group tolerance, providing the functionalized 2-oxazolines with retention of the configuration at the C(4) stereogenic center of the 2-oxazolines. Widely accessible β-amino alcohols can be used in this approach, and the cyclization of N-(2-hydroxyethyl)amides provides the desired 2-oxazolines in up to 99% yield. The mechanism of the reaction was studied by monitoring the reaction using spectral and analytical methods, whereby an 18O-labeling experiment furnished valuable insights. The initial step involves a stoichiometric reaction between the substrate and TAP-1, which leads to the in situ generation of the catalyst, a catechol cyclic phosphate, as well as to a pyrocatechol phosphate and two possible active intermediates. The dehydrative cyclization was also successfully conducted on the gram scale.
Insights into the antiproliferative mechanism of (C^N)-chelated half-sandwich iridium complexes
Ramos, Robin,Zimbron, Jérémy M.,Thorimbert, Serge,Chamoreau, Lise-Marie,Munier, Annie,Botuha, Candice,Karaiskou, Anthi,Salmain, Michèle,Sobczak-Thépot, Jo?lle
supporting information, p. 17635 - 17641 (2020/12/30)
Transition metal-based anticancer compounds, as an alternative to platinum derivatives, are raising scientific interest as they may present distinct although poorly understood mechanisms of action. We used a structure-activity relationship-based methodology to investigate the chemical and biological features of a series of ten (C^N)-chelated half-sandwich iridiumIII complexes of the general formula [IrCp?(phox)Cl], where (phox) is a 2-phenyloxazoline ligand forming a 5-membered metallacycle. This series of compounds undergoes a fast exchange of their chlorido ligand once solubilised in DMSO. They were cytotoxic to HeLa cells with IC50 values in the micromolar range and induced a rapid activation of caspase-3, an apoptosis marker. In vitro, the oxidative power of all the complexes towards NADH was highlighted but only the complexes bearing substituents on the oxazoline ring were able to produce H2O2 at the micromolar range. However, we demonstrated using a powerful HyPer protein redox sensor-based flow cytometry assay that most complexes rapidly raised intracellular levels of H2O2. Hence, this study shows that oxidative stress can partly explain the cytotoxicity of these complexes on the HeLa cell line and gives a first entry to their mechanism of action. This journal is
Chemoselective Synthesis of α-Amino-α-cyanophosphonates by Reductive Gem-Cyanation-Phosphonylation of Secondary Amides
Chen, Ting-Ting,Wang, Ai-E,Huang, Pei-Qiang
supporting information, p. 3808 - 3812 (2019/05/24)
A novel approach to α-amino-α-cyanophosphonates has been developed. The method features a Tf2O-mediated reductive geminal cyanation/phosphonylation of secondary amides. Mild reaction conditions, high bond-forming efficiency, inexpensive readily available starting materials, and good to excellent yields with wide functional group compatibility constitute the main advantages of this method. The protocol can be run on a gram scale.
Iron(iii)-catalyzed selective N-O bond cleavage to prepare tetrasubstituted pyridines and 3,5-disubstituted isoxazolines from: N -vinyl-α,β-unsaturated ketonitrones
Chen, Chun-Hua,Wu, Qing-Yan,Wei, Cui,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
, p. 2722 - 2729 (2018/06/29)
An iron(iii)-catalyst controlled cyclization and selective N-O bond cleavage of N-vinyl-α,β-unsaturated nitrones has been achieved under mild conditions to access tetrasubstituted pyridines and 3,5-disubstituted isoxazolines in moderate to good yields. The tetrasubstituted pyridines were afforded with FeCl3 as a catalyst while using FeCl3·6H2O combined with 1,10-phenanthroline delivered isoxazolines. The regioselectivity for cyclization of styrenyl groups in N-vinyl-α,β-unsaturated nitrones was completely different during the formation of pyridines and isoxazolines. A rational mechanism for the formation of pyridines and isoxazolines was proposed based on the further control experimental studies. The isoxazolines can be converted to a novel bidentate N-ligand over four steps and an epoxypyridine scaffold was obtained from N-vinyl nitrone when copper(ii) acetate in combination with the prepared bidentate N-ligand was used.
A [3+3] cyclization strategy for asymmetric synthesis of alkyl substituted piperidine-2-ones using 1,2-cyclic sulfamidates: A formal synthesis of (S)-coniine from l-norvaline
Karanfil, Abdullah,Balta, Berrin,Eskici, Mustafa
, p. 10218 - 10229,12 (2020/09/02)
Regioselective ring-opening reactions of a set of representative 1,2-cyclic sulfamidates with lithium triethylorthopropiolate proceeded efficiently to deliver the corresponding δ-amino-α,β-unsaturated esters after acidic hydrolysis. Hydrogenation of the unsaturated esters and subsequent thermal cyclization afforded the related alkyl substituted piperidine-2-ones. This approach represents a novel [3+3] cyclization strategy for the asymmetric synthesis of alkyl substituted piperidin-2-ones. Efficiency of the cyclization process is illustrated by a formal asymmetric synthesis of (S)-coniine from l-norvaline.
New chiral ionic liquids based on imidazolinium salts
Winkel, Andreas,Wilhelm, Rene
experimental part, p. 2344 - 2350 (2010/03/04)
The preparation and application of a new series of chiral ionic liquids are described. The salts are based on imidazolinium cations. Some of the cations also incorporated an axial chirality at the C(2) position next to the central chirality. These cations
Enzyme-like chemoselective acylation of alcohols in the presence of amines catalyzed by a tetranuclear zinc cluster
Ohshima, Takashi,Iwasaki, Takanori,Maegawa, Yusuke,Yoshiyama, Asako,Mashima, Kazushi
, p. 2944 - 2945 (2008/09/20)
Acylation of alcohols and amines is one of the most fundamental reactions. Due to the greater nucleophilicity of the amino group compared to the hydroxyl group, complete N-acylation occurs. Only an enzymatic reaction can promote a highly selective O-acyla
A simple method removing 2-oxazolidinone and 2-hydroxyethylamine auxiliaries in methoxide-carbonate systems for synthesis of planar-chiral nicotinate
Kanomata, Nobuhiro,Maruyama, Satoshi,Tomono, Katsuhito,Anada, Shinnosuke
, p. 3599 - 3603 (2007/10/03)
A facile and practical removal of 2-oxazolidinone and 2-hydroxyethylamine auxiliaries was accomplished by treating the corresponding N-acyl-2-oxazolidinone and N-(2-hydroxyethyl)amide derivatives in simple methoxide-carbonate systems. The presence of excess DMC (dimethyl carbonate) accelerates the N-acyl bond cleavage for those substrates under mild reaction conditions, and the present method was found to be useful especially for the synthesis of planar-chiral nicotinate.
Synthesis and Application of Chiral Phosphino-Imidazoline Ligands: Ir-Catalyzed Enantioselective Hydrogenation
Menges, Frederik,Neuburger, Markus,Pfaltz, Andreas
, p. 4713 - 4716 (2007/10/03)
(Matrix Presented) A series of chiral phosphino-imidazolines (PHIM ligands) 1a-j with different substituents at the stereogenic center, the nitrogen atom of the imidazoline ring, and at the phosphorus atom were synthesized. Iridium complexes derived from
