3674-13-3Relevant academic research and scientific papers
A Metal-Free Domino Process for Regioselective Synthesis of 1,2,4-Trisubstituted Pyrroles: Application toward the Formal Synthesis of Ningalin B
Kumar, Virendra,Awasthi, Annapurna,Metya, Abhisek,Khan, Tabrez
, p. 11581 - 11595 (2019/10/02)
A new one-pot, transition-metal, acid/base-free domino process is developed for the regioselective synthesis of 1,2,4-trisubstituted pyrroles. The process involves 1,3-dipolar cycloaddition of unsymmetrical azomethine ylide resulting from the thermal C-C bond cleavage of unactivated aziridines with β-bromo-β-nitrostyrene, followed by a cascade of elimination and aromatization reaction sequence to preferentially furnish 1,2,4-trisubstituted pyrroles instead of the expected 1,2,3-trisubstituted pyrroles, in good to excellent yields. Further, the application of the methodology for the formal synthesis of ningalin B is delineated.
How Reaction Conditions May Influence the Regioselectivity in the Synthesis of 2,3-Dihydro-1,4-benzoxathiine Derivatives
Casiraghi, Andrea,Valoti, Ermanno,Suigo, Lorenzo,Artasensi, Angelica,Sorvillo, Erica,Straniero, Valentina
, p. 13217 - 13227 (2018/10/24)
The exploration of different reaction conditions aiming to obtain both 2,3-dihydro-1,4-benzoxathiine-2-yl derivatives and 2,3-dihydro-1,4-benzoxathiine-3-yl ones is reported. The treatment of 1,2-mercaptophenol with an organic base and a specific 2-bromo acrylate results in a solvent- and substrate-dependent exclusive solvation of O- and S-anions, thus managing the regioselectivity.
Diaziridyl Ether of Bisphenol A
Kang, Seohyun,Moon, Hyun Kyung,Yoon, Hyo Jae
, p. 4068 - 4076 (2018/06/19)
Increased complexities in applications involving curable materials virtually need new materials that can overcome the limitations of existing ones. Resins, the structure of which is based on bisphenol A backbone terminated with three membered N-heterocycles - aziridines - have been synthesized, and their thermal-curing performance in solution and solid state was evaluated by NMR and FT-IR spectroscopies, differential scanning calorimetry, and single lap shear strength test and compared with that of analogous epoxy resin (diglycidyl ether of bisphenol A; DGEBA). Results reveal that the chemical reactivity of the aziridine-based resins is fine-tunable by controlling the N-substituent of aziridine. These resins can undergo ring-opening polymerization in the presence of various curing agents under unprecedentedly mild conditions and show remarkably rapid curing rate, wide substrate scope, and excellent chemoselectivity as compared to the analogous epoxy resin. Our results demonstrate superb curing ability of aziridine, making it promising for applications in materials and polymer sciences.
Halogen bonding enhances activity in a series of dual 5-HT6/D2 ligands designed in a hybrid bioisostere generation/virtual screening protocol
Staroń, Jakub,Warszycki, Dawid,Kurczab, Rafa?,Sata?a, Grzegorz,Bugno, Ryszard,Hogendorf, Adam,Bojarski, Andrzej J.
, p. 54918 - 54925 (2016/07/06)
A novel hybrid bioisostere generation/virtual screening method combined with narrowing of chemical space through similarity to compounds that are active at the second target was successfully applied for the development of structurally new dual 5-HT6/D2 receptor ligands. Consequently, a series of derivatives of the found hit 1d (N-[2-(dimethylamino)ethyl]-N-(2-phenylethyl)aniline) was synthesized. The most active 5-HT6/D2 ligands also showed affinity for 5-HT7R and 5-HT2AR. The para-chloroaniline derivative was identified as a potent dual 5-HT6/5-HT7 receptor antagonist (Ki = 24 nM and Kb = 30 nM, Ki = 4 nM and Kb = 1.4 nM, respectively). In the case of halogen-containing compounds, interesting structure-activity relationships were observed at 5-HT6, D2 and 5-HT7 receptors, and the ligand-receptor complexes were subsequently examined using a molecular modelling approach that combined quantum-polarized ligand docking (QPLD) and Molecular-Mechanics-Generalized-Born/Surface Area (MM/GBSA) free-energy calculation, which permitted the identification of putative halogen binding pockets.
Mesoporous silica-supported copper-catalysts for homocoupling reaction of terminal alkynes at room-temperature
Li, Hongling,Yang, Min,Zhang, Xia,Yan, Liang,Li, Jing,Qi, Yanxing
, p. 1343 - 1349 (2013/05/21)
Amine-functionalized mesoporous silica-supported copper catalysts SBA-15@amine-Cu and SBA-15@Oamine-Cu were prepared and proved to be efficient and reusable for homocoupling of terminal alkynes at room temperature with air as the oxidant. SBA-15@amine-Cu exhibited better recyclability than SBA-15@Oamine-Cu. The differences in the catalytic performances of the catalysts could be ascribed to catalyst structure and the interaction between copper and the supports. The as-prepared catalysts were systematically characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), high resolution-transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen physical adsorption. The analysis indicated that the mesoporous structure of the materials was retained during the immobilization process. XPS results suggested that the as-prepared catalysts were not obtained by a simple physical adsorption of CuCl on the supports. It is noted that, for aliphatic alkynes, the catalytic activity of SBA-15@amine-Cu is even higher than that of the homogeneous copper catalytic system and that of some previously reported heterogeneous systems.
Nucleophilic trifluoromethylation of aziridinyl ketones: A convenient access to fluorinated aziridinyl alcohols
Mlostoń, Grzegorz,Obijalska, Emilia,Zi?bacz, Paulina,Matyszewski, Krzysztof,Urbaniak, Katarzyna,Linden, Anthony,Heimgartner, Heinz
, p. 192 - 197 (2013/11/19)
A convenient synthesis of α-(aziridin-2-yl)-α-(trifluoromethyl) alcohols starting with ethyl aziridine-2-carboxylates is reported. Grignard reaction with the corresponding Weinreb amides led to aziridin-2-yl ketones, and subsequent treatment with Ruppert-Prakash reagent gave the trimethylsilylated target compounds as mixtures of diastereoisomers, which were desilylated with TBAF. In the case of ethyl 1-((S)-1-phenylethyl)aziridine-2-carboxylate, (S,S)- and (S,R)-aziridin-2-yl ketones were obtained, separated chromatographically and transformed into the desired enantiomerically pure α-trifluoromethylated alcohols.
Direct sustainable bromination of alkenes in aqueous media and basic ionic liquids
Primerano, Patrizia,Cordaro, Massimiliano,Scala, Angela
, p. 4061 - 4063 (2013/07/25)
Electron-rich and electron-poor alkenes have been dibrominated using a rapid and sustainable procedure. The reactions were conducted in aqueous medium and basic ionic liquids which catalyzed the direct addition of bromine. The protocol leads to remarkable results, high yields under mild conditions, complete chemo- and stereo-selectivity and allows the recycling of ionic liquids, reducing costs, and environmental impact.
Chemoenzymatic synthesis of piperoxan, prosympal, dibozane, and doxazosin
Rouf, Abdul,Gupta, Pankaj,Aga, Mushtaq A.,Kumar, Brijesh,Chaubey, Asha,Parshad, Rajinder,Taneja, Subhash C.
, p. 1615 - 1623 (2013/02/22)
The synthesis of both enantiomers of 1,4-benzodioxan-2-carboxylic acid 1, a key synthetic intermediate for the therapeutic agents piperoxan, prosympal, dibozane, and doxazosin was achieved with good yields and high enantioselectivities via the Arthrobacter sp. lipase catalyzed kinetic resolution of ester (±)-17a. The influence of the co-solvents and the immobilization of the lipase upon kinetic resolution demonstrated that immobilized whole cells, in the presence of n-butanol as a co-solvent, resulted in the optimal resolution of the substrate (ee ～99%, E = 535) at 258 mmol (50 g/L) substrate concentration.
Anionic [4+3] heteroannulation of 2-azidoacrylates: A modular synthesis of 2-benzazepin-1-ones
Dinda, Bidyut Kumar,Jana, Amit Kumar,Mal, Dipakranjan
supporting information; experimental part, p. 3999 - 4001 (2012/06/01)
2-Azidoacrylates undergo [4+3] annulation with phthalides under anionic conditions at low temperatures to furnish 5-hydroxy-2-benzazepinones, the formation of which represents a new concept for the construction of azepines as well as a new reactivity of 2-azidoacrylates.
Robust eco-friendly protocol for the preparation of γ-hydroxy- α,β-acetylenic esters by sequential one-pot elimination-addition of 2-bromoacrylates to aldehydes promoted by LTMP in 2-MeTHF
Pace, Vittorio,Castoldi, Laura,Alcantara, Andres R.,Holzer, Wolfgang
supporting information; experimental part, p. 1859 - 1863 (2012/08/14)
An efficient and widely applicable preparation of γ-hydroxy-α, β-acetylenic esters is described by means of a one-pot dehydrobromination of a 2-bromoacrylate ester with LTMP followed by the electrophilic addition of the transient propiolate to different aldehydes in the eco-friendly solvent 2-MeTHF. The Royal Society of Chemistry 2012.
