17236-58-7Relevant articles and documents
o-directed lithiation of acylated hydroxythiophenes
Vendina, Ineta,Parkova, Anete,Trapencieris, Peteris
, p. 1565 - 1572 (2014)
O-Carbamates derived from 2-hydroxy- and 3-hydroxy-thiophenes generated o-directed carbanions, which were transformed to the corresponding methyl sulfides and methyl and trimethylsilyl substituted thiophenes.
Hemicucurbit[6]uril-induced aerobic oxidation of heterocyclic compounds
Cong, Hang,Yamato, Takehiko,Tao, Zhu
, p. 287 - 293 (2013)
The aerobic oxidation of furan in aqueous solution in the presence of HemiQ[6] has been investigated, and the product furan-2,5-diol is stabilized by encapsulation of HemiQ[6], which could be transformed to the dione confirmation in acidic solution and escape from the macrocyclic compound. The 1H NMR titration experiments of the host-guest interaction at different pH values suggest protonation should improve the encapsulation, and therefore an unique property that HemiQ[6] can be protonated has been revealed. The oxidizing kinetics suggests that the procedure is a consecutive reaction with a series of constants k1 = 2.9 × 10-2 min-1, k 2 = 2.7 × 10-2 min-1, and k3 = 5.7 × 10-3 min-1, respectively. The kinetic investigation at pD = 2.0 indicates the HemiQ[6]-catalytic oxidation of furan could be accelerated by acidification. As a consequence, a plausible mechanism has been established on the above evidences. 2-Methylfuran is employed to give the product 2-methylfuran-5-ol exhibiting a satisfied activity in this aerobic oxidation with the supramolecular catalysis of HemiQ[6], but the oxidation of thiophene is very slow in either neutral or acidic condition.
BIARYL HYDROXYTHIOPHENE GROUP IV TRANSITION METAL POLYMERIZATION CATALYSTS WITH CHAIN TRANSFER CAPABILITY
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, (2022/02/05)
Catalyst systems that include a chain transfer agent and a metal-ligand complex according to formula (I).
An efficient base and H2O2 free protocol for the synthesis of phenols in water and oxygen using spinel CuFe2O4 magnetic nanoparticles
Chutia, Rituparna,Chetia, Bolin
, p. 1925 - 1936 (2020/08/13)
An efficient base and H2O2 free protocol was used for the synthesis of phenols from boronic acids using biogenic CuFe2O4 magnetic nanoparticles as catalyst at room temperature in water and oxygen. The catalyst was prepared using the flowers of Lantana camara. The size of the nanoparticles was 4.27 nm. Base free and ligand free protocol, less time, excellent yields, room temperature, biogenic synthesis of the catalyst, use of O2 as an environmentally friendly oxidant are the advantages of the present protocol. The recyclability of the catalyst was for 5 cycles without loss of magnetic property or catalytic activity.
Trinuclear Mn2+/Zn2+based microporous coordination polymers as efficient catalysts foripso-hydroxylation of boronic acids
Bora, Sanchay J.,Dutta, Anurag,Goswami, Shyam,Guha, Ankur K.,Paul, Rima,Thakur, Ashim J.
, p. 5454 - 5462 (2020/05/16)
Two microporous coordination polymers based on hourglass trinuclear building units, [Mn3(bpdc)3(bpy)]·2DMF and [Zn3(bpdc)3(bpy)]·2DMF·4H2O (bpdc = 4,4′-biphenyl dicarboxylic acid, bpy = 4,4′-bipyridine), have been synthesized under solvothermal conditions employing DMF as the solvent. Each structure consists of two crystallographically distinct M2+(M1 and M2) centers that are connectedviacarboxylate bridges from six bpdc ligands, generating a trinuclear metal cluster, [M3(bpdc)3(bpy)]. Cluster representation of the structure resulted in an interpenetrated net of rarehextopological type. Catalytic activities of the CPs have been assessed for the oxidative hydroxylation of phenylboronic acids (PBAs) using aqueous hydrogen peroxide (H2O2). Various substituted aryl/hetero-arylboronic acids RB(OH)2[R = phenyl, 2,4-difluorophenyl, 4-aminophenyl, 2-thiopheneetc.] underwentipso-hydroxylation smoothly at room temperature to generate the corresponding phenols in excellent yields. The main advantages of this protocol are the aqueous medium reaction, heterogeneous catalytic system, and short reaction time with excellent yield.
BIARYL PHENOXY GROUP IV TRANSITION METAL CATALYSTS FOR OLEFIN POLYMERIZATION
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, (2020/05/14)
Embodiments are directed to catalyst systems comprising at least one metal ligand complex and to processes for polyolefin polymerization incorporating the catalyst systems. The metal ligand complexes have the following structures:
A simple, fast and excellent protocol for the synthesis of phenols using CuFe 2O 4 magnetic nanoparticles
Chutia, Rituparna,Chetia, Bolin
, (2019/06/27)
Abstract: This paper describes a very mild, quick and simple protocol for the synthesis of phenols using CuFe 2O 4 magnetic nanoparticles as a catalyst. The nanosized catalyst has an average diameter of 17.63 nm. The magnetic nanoparticles were characterized by SEM, EDX, VSM, XRD and TEM analysis. The synthesis of phenols from phenylboronic acids using H 2O 2 as an oxidant proceeded very well with excellent yields. Heterogeneous catalyst, easy recyclability, mild reaction conditions, short reaction time added as an advantage for the present protocol. Graphical Abstract: A very mild, quick and efficient protocol has been designed for the preparation of phenols from phenyl boronic acids using CuFe 2O 4 Magnetic Nanoparticles (MNPs) as a catalyst. Heterogeneous catalyst, easy recyclability added as an advantage for the protocol.[Figure not available: see fulltext.].
Cellulose as recyclable organocatalyst for ipso-hydroxylation of arylboronic acids
Laskar, Khairujjaman,Paul, Subham,Bora, Utpal
, (2019/08/26)
Cellulose catalyzed oxidative hydroxylation of aryl and hetero-arylboronic acids to the corresponding phenols under metal and base free strategy has been demonstrated. The sustainable ipso-hydroxylation takes place using hydrogen peroxide as an oxidant in water under mild condition in shorter period of time. Interestingly, easy recovery and reusability of heterogeneous catalyst without significant loss in catalytic yield makes the protocol environmentally benign.
Heterogeneous Palladium–Chitosan–CNT Core–Shell Nanohybrid Composite for Ipso-hydroxylation of Arylboronic Acids
Shin, Eun-Jae,Kim, Han-Sem,Joo, Seong-Ryu,Shin, Ueon Sang,Kim, Seung-Hoi
, (2019/03/19)
Abstract: A novel palladium-nanohybrid (Pd–Chitosan–CNT) catalytic composite has been developed using CNT–chitosan nanocomposite and palladium nitrate. The prepared catalytic platform displays excellent catalytic reactivity for the ipso-hydroxylation of various arylboronic acids with a mild oxidant aqueous H2O2 at room temperature, affording the corresponding phenols in excellent yields. Significantly, the easy recovery and reusability by simple manipulation demonstrate the green credentials of this catalytic platform. Graphical Abstract: [Figure not available: see fulltext.]
Size-tunable ZnO nanotapes as an efficient catalyst for oxidative chemoselective C–B bond cleavage of arylboronic acids
Phukan, Shreemoyee,Mahanta, Abhijit,Rashid, Md. Harunar
, p. 58 - 66 (2018/06/07)
Herein, we report a simple but effective chemical approach for the synthesis of size-tunable ZnO nanotapes by precipitation method in the presence of phytochemicals present in the flower extract of Lantana camara plant. The electron microscopic study confirmed that the size of ZnO nanotapes can be systematically controlled by varying the concentration of either flower extract or metal ions and the flower extract played the key role in controlling the growth of ZnO nanotapes. The phase and crystalline analysis was carried out by X-ray diffraction method which indicated that ZnO nanostructures are highly crystalline in nature and are free from any impurities. The synthesized ZnO nanostructures exhibited interesting optical properties as investigated by UV–vis absorption and photoluminescence spectroscopy. Further the surface functionalities affect the optical properties of ZnO nanostructures which possess relatively strong UV emissions; a blue emission and a green emission. The synthesized ZnO nanostructures showed excellent catalytic properties in the ipso-hydroxylation of different aryl/ hetero-arylboronic acid to phenol in a relatively greener reaction conditions. These catalysts are highly stable and are re-usable upto six cycles of ipso-hydroxylation without losing its catalytic properties.
