25639-25-2Relevant academic research and scientific papers
Synthesis of a putative advanced intermediate en route to elisabethin A
Steiner, Sebastian,G?rtner, Peter,Enev, Valentin S.
, p. 4536 - 4542 (2016)
The first generation synthesis of an advanced intermediate en route to elisabethin A is described.
Titanium cis-1,2-Diaminocyclohexane Salalen Catalysts of Outstanding Activity and Enantioselectivity for the Asymmetric Epoxidation of Nonconjugated Terminal Olefins with Hydrogen Peroxide
Lansing, Markus,Engler, Hauke,Leuther, Tobias M.,Neud?rfl, J?rg-M.,Berkessel, Albrecht
, p. 3706 - 3709 (2016)
We report a new and readily accessible class of titanium salalen complexes derived from cis-1,2-diaminocyclohexane (cis-DACH) and fluorinated salicylic aldehyde derivatives. With aqueous hydrogen peroxide as the oxidant, these complexes catalyze the epoxidation of terminal, nonconjugated olefins in high yields with high enantioselectivities. We furthermore discovered that the addition of certain acidic or basic co-catalysts significantly accelerated the epoxidation. For example, in the presence of 1 mol % Ti catalyst and 1 mol % pentafluorobenzoic acid, 1-octene epoxidation (95 % ee) was completed at room temperature within 8 h. The catalytic process was compatible with many functional groups (e.g., ethers, esters, halides, nitriles, and nitro groups), whereas free hydroxy groups appeared to slow down the reaction to some extent. Catalyst recycling was possible.
Rational design 2-hydroxypropylphosphonium salts as cancer cell mitochondria-targeted vectors: Synthesis, structure, and biological properties
Amerhanova, Syumbelya K.,Dimukhametov, Mudaris N.,Gubaidullin, Aidar T.,Islamov, Daut R.,Litvinov, Igor A.,Lyubina, Anna P.,Mironov, Vladimir F.,Nemtarev, Andrey V.,Pashirova, Tatiana N.,Titov, Eugenii A.,Tsepaeva, Olga V.,Voloshina, Alexandra D.
, (2021/11/01)
It has been shown for a wide range of epoxy compounds that their interaction with triphenylphosphonium triflate occurs with a high chemoselectivity and leads to the formation of (2-hydroxypropyl)triphenylphosphonium triflates 3 substituted in the 3-position with an alkoxy, alkylcarboxyl group, or halogen, which were isolated in a high yield. Using the methodology for the disclosure of epichlorohydrin with alcohols in the presence of boron trifluoride ether-ate, followed by the substitution of iodine for chlorine and treatment with triphenylphosphine, 2-hydroxypropyltriphenylphosphonium iodides 4 were also obtained. The molecular and supramolec-ular structure of the obtained phosphonium salts was established, and their high antitumor activity was revealed in relation to duodenal adenocarcinoma. The formation of liposomal systems based on phosphonium salt 3 and L-α-phosphatidylcholine (PC) was employed for improving the bioavailabil-ity and reducing the toxicity. They were produced by the thin film rehydration method and exhibited cytotoxic properties. This rational design of phosphonium salts 3 and 4 has promising potential of new vectors for targeted delivery into mitochondria of tumor cells.
Synthesis and characterization of a new poly α-amino acid Co(II)-complex supported on magnetite graphene oxide as an efficient heterogeneous magnetically recyclable catalyst for efficient free-coreductant gram-scale epoxidation of olefins with molecular oxygen
Kazemnejadi, Milad,Mahmoudi, Boshra,Sharafi, Zeinab,Nasseri, Mohammad Ali,Allahresani, Ali,Esmaeilpour, Mohsen
, p. 59 - 69 (2019/06/13)
A novel magnetic nanocomposite was prepared by immobilization of a cobalt complex of a synthetic poly α-amino acid on Fe3O4-doped graphene oxide (GO/Fe3O4@PAA Co(II)) and was demonstrated to be a highly efficient catalyst for the epoxidation of olefins in mild conditions. PAA was synthesized through a multi-step synthesis, first by a poly condensation reaction of salicylaldehyde followed by the Strecker synthesis. The synthesized nanocomposite was characterized by various analytical and spectroscopic methods including FTIR, ICP, XRD, EDX, XPS, FE-SEM, TEM, TGA, VSM and DLS analyses. A wide variety of olefins could be tolerated toward epoxidation in the presence of molecular oxygen without the need for any co-reductant. The magnetic nanocomposite could be readily separated by a magnet from the mixture and reused for several times without any significant reactivity loss, which represents its potential for practical and industrial application. Also, the scalability of the process was investigated in this work.
Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
supporting information, p. 513 - 518 (2019/01/14)
Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
Calix[8]arene as New Platform for Cobalt-Salen Complexes Immobilization and Use in Hydrolytic Kinetic Resolution of Epoxides
Abdellah, Ibrahim,Martini, Cyril,Dos Santos, Amandine,Dragoe, Diana,Guérineau, Vincent,Huc, Vincent,Schulz, Emmanuelle
, p. 4761 - 4767 (2018/10/02)
Eight cobalt-salen complexes have been covalently attached to a calix[8]arene platform through a flexible linker by a procedure employing Click chemistry. The corresponding well-defined catalyst proved its efficiency in the hydrolytic kinetic resolution (HKR) of various epoxides through an operative bimetallic cooperative activation, demonstrating highly enhanced activity when compared to its monomeric analogue. As an insoluble complex, this multisite cobalt-salen catalyst could be easily recovered and reused in successive catalytic runs. Products were isolated by a simple filtration with virtually no cobalt traces and without requiring a prior purification by flash chromatography.
Synthesis of Vicinal Dichlorides via Activation of Aliphatic Terminal Epoxides with Triphosgene and Pyridine
Cleveland, Alexander H.,Fronczek, Frank R.,Kartika, Rendy
, p. 3367 - 3377 (2018/03/26)
Herein we report a novel synthetic reaction to convert unactivated terminal aliphatic epoxide to alkyl vicinal dichloride based on triphosgene-pyridine activation. Our methodology is operationally simple and readily tolerated by a broad of scope of substrates as well as protecting groups. Furthermore, these mild conditions generally yield clean reaction mixtures that are free of byproducts upon aqueous workup.
Co(II) Schiff base complex decorated on polysalicylaldehyde as an efficient, selective, heterogeneous and reusable catalyst for epoxidation of olefins in mild and self-coreductant conditions
Kazemnejadi, Milad,Shakeri, Alireza,Nikookar, Mahsa,Mohammadi, Mohammad,Esmaeilpour, Mohsen
, p. 6889 - 6910 (2017/10/05)
Abstract: A new Co(II)-Schiff base complex was decorated on a polysalicylaldehyde (PSA) framework and used as a selective and efficient catalyst for the epoxidation of alkenes in the presence of O2 as a green source of oxygen without aco-reductant. The catalyst was characterized step by step by FTIR, UV–Vis, 1H NMR, TGA, CHN, XPS and EDX analyses. Loading an amount of Co ions in the catalyst as well as its leaching amount were studied by an ICP-OES instrument. The catalyst demonstrated excellent activity for the of a variety of alkenes in a mild, inexpensive and efficient protocol. Also, the catalyst can be simply recovered from the reaction mixture and reused for several times without any noteiceable loss in its activity. Reaction parameters including temperature, oxygen flow volume, catalyst amount and solvent were screened by reaction time. Catalytic studies including XPS spectroscopy and some blank experiments were performed to obtain an initial insight into the reaction mechanism. Also, the reactivity of the novel catalyst was evaluated as the turnover frequency. Graphical Abstract: A new and efficient protocol have been developed for the selective epoxidation of olefins using a heterogeneous recyclable Co(II)-Schiff base complex of polysalicylaldehyde in mild and self-coreductant conditions by molecular oxygen.
Flexible tetrahydropyran synthesis from homopropargylic alcohols using sequential Pd-Au catalysis
Kim, Jungjoon,Jeong, Wook,Rhee, Young Ho
supporting information, p. 242 - 245 (2017/11/27)
A flexible synthetic method toward highly substituted tetrahydropyran is reported. The key transformation involves atom-efficient sequential metal catalysis consisting of Pd-catalyzed addition of homopropargylic alcohols to alkoxyallene and the subsequent
Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
supporting information, p. 3990 - 4001 (2017/11/22)
New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
