26945-93-7Relevant academic research and scientific papers
Palladium-Catalyzed Oxidation of β-C(sp3)-H Bonds of Primary Alkylamines through a Rare Four-Membered Palladacycle Intermediate
Bunescu, Ala,Ernst, Martin,Hartwig, John F.,Qiu, Yehao,Su, Bo,Zuend, Stephan J.
supporting information, p. 7912 - 7919 (2020/05/22)
Site-selective functionalizations of C-H bonds are often achieved with a directing group that leads to five- or six-membered metallacyclic intermediates. Analogous reactions that occur through four-membered metallacycles are rare. We report a challenging palladium-catalyzed oxidation of primary C-H bonds β to nitrogen in an imine of an aliphatic amine, a process that occurs through a four-membered palladacyclc intermediate. The success of the reaction relies on the identification, by H/D exchange, of a simple directing group (salicylaldehyde) capable of inducing the formation of this small ring. To gain insight into the steps of the catalytic cycle of this unusual oxidation reaction, a series of mechanistic experiments and density functional theory (DFT) calculations were conducted. The experimental studies showed that cleavage of the C-H bond is rate-limiting and formation of the strained four-membered palladacycle is thermodynamically uphill. DFT calculations corroborated these conclusions and suggested that the presence of an intramolecular hydrogen bond between the oxygen of the directing group and hydroxyl group of the ligating acetic acid is crucial for stabilization of the palladacyclic intermediate.
PROCESS FOR PREPARATION OF AMINO ALCOHOLS
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Paragraph 0065, (2020/01/31)
A process for the preparation of amino alcohols includes condensing a compound of Formula (II), a stereoisomer, a tautomer, or a salt thereof with a compound of Formula (IlIa) or Formula (Illb), a stereoisomer, a tautomer, or a salt thereof to form a condensation product; hydroxylating or acyloxylating the condensation product in the presence of an oxidant to obtain a hydroxylation or acyloxylation product; and subjecting the hydroxylation or acyloxylation product to one or more subsequent reactions comprising a hydrolysis reaction, alcohol deprotection, an amino lysis reaction, or a combination of two or more thereof to obtain an amino alcohol of Formula (I).
Coumaraz-2-on-4-ylidene: Ambiphilic N-Heterocyclic Carbenes with a Tunable Electronic Structure
Song, Hayoung,Kim, Hyunho,Lee, Eunsung
supporting information, p. 8603 - 8607 (2018/07/14)
Herein, a coumaraz-2-on-4-ylidene (1) as a new example of an ambiphilic N-heterocyclic carbene, having electronic properties that can be fine-tuned, is reported. The N-carbamic and aryl groups on the carbene carbon center provide exceptionally high electrophilicity and nucleophilicity simultaneously to the carbene center, as evidenced by the 77Se NMR chemical shifts of their selenoketone derivatives and the CO stretching strengths of their rhodium carbonyl complexes. Since the precursors of 1 could be synthesized from various functionalized Schiff bases in a practical and scalable manner, the electronic properties of 1 can be fine-tuned in a quantitative and predictable way by using the Hammett σ constant of the functional groups on aryl ring. The facile electronic tuning capability of 1 may be applicable to eliciting novel properties in main-group and transition-metal chemistry.
Investigation of the dinuclear effect of aluminum complexes in the ring-opening polymerization of ε-caprolactone
Hsu, Chiao-Yin,Tseng, Hsi-Ching,Vandavasi, Jaya Kishore,Lu, Wei-Yi,Wang, Li-Fang,Chiang, Michael Y.,Lai, Yi-Chun,Chen, Hsing-Yin,Chen, Hsuan-Ying
, p. 18851 - 18860 (2017/04/10)
A series of aluminum (Al) complexes bearing hydrazine-bridging Schiff base and salen ligands were synthesized and investigated as catalysts for the ring-opening polymerization of ε-caprolactone (CL). The introduction of steric bulky groups increases the catalytic activity of the corresponding mononuclear aluminum complex. However, the opposite phenomenon was observed in dinuclear Al complexes bearing salen ligands because the steric repulsion reduced the cooperative activation mechanism in the dinuclear Al system. Among these Al complexes, LN2Bu-Al2Me4 bearing a hydrazine-bridging Schiff base ligand had the highest catalytic activity, approximately 3- to 11-fold higher than that of dinuclear Al complexes bearing salen ligands and mononuclear Al complexes bearing Schiff base ligands. Density functional theory calculations revealed that the mechanism of the coordination of CL to one Al center was initiated by the benzyl alkoxide of another Al center.
Oxazine Ring-Related Vibrational Modes of Benzoxazine Monomers Using Fully Aromatically Substituted, Deuterated, 15N Isotope Exchanged, and Oxazine-Ring-Substituted Compounds and Theoretical Calculations
Han, Lu,Iguchi, Daniela,Gil, Phwey,Heyl, Tyler R.,Sedwick, Victoria M.,Arza, Carlos R.,Ohashi, Seishi,Lacks, Daniel J.,Ishida, Hatsuo
, p. 6269 - 6282 (2017/09/01)
Polymerization of benzoxazine resins is indicated by the disappearance of a 960-900 cm-1 band in infrared spectroscopy (IR). Historically, this band was assigned to the C-H out-of-plane bending of the benzene to which the oxazine ring is attach
Cobalt(II), copper(II), zinc(II) and palladium(II) Schiff base complexes: Synthesis, characterization and catalytic performance in selective oxidation of sulfides using hydrogen peroxide under solvent-free conditions
Khorshidifard, Mahsa,Rudbari, Hadi Amiri,Askari, Banafshe,Sahihi, Mehdi,Farsani, Mostafa Riahi,Jalilian, Fariba,Bruno, Giuseppe
, p. 1 - 13 (2015/05/05)
An asymmetric bidentate Schiff-base ligand (HL: 2-tert-butyliminomethyl-phenol) was prepared from the reaction of salicylaldehyde and tert-butylamine. Cobalt(II), copper(II), zinc(II) and Pd(II) complexes, CoL2, CuL2, ZnL2 and PdL2, were synthesized from the reaction of CoCl2·6H2O, CuCl2·2H2O, Zn(NO3)2·6H2O and PdCl2 with the bidentate Schiff base ligand HL in methanol. The ligand and its metal complexes were characterized by elemental analysis (CHN), FT-IR and UV-Vis spectroscopy. In addition, 1H and 13C NMR techniques were employed for characterization of the ligand (HL) and the diamagnetic complexes (ZnL2 and PdL2). The molecular structures of all the complexes were determined by the single crystal X-ray diffraction technique. The crystallographic data reveal that in all the complexes the metal centers are four-coordinated by two phenolate oxygen and two imine nitrogen atoms of two Schiff base ligands. The geometry around the metal center in the CoL2, CuL2 and ZnL2 complexes is a distorted tetrahedral and for PdL2 it is square-planar. The catalytic activity of these complexes has been evaluated for the selective oxidation of sulfides with the green oxidant 35% aqueous H2O2 under solvent free conditions. For all the catalysts, using optimized reaction conditions, different sulfides were converted to the corresponding sulfones. ZnL2 showed a higher catalytic performance for the oxidation of the different sulfides to the corresponding sulfones.
Synthesis, characterization, and catalytic activity of titanium iminophenoxide complexes in relation to the ring-opening polymerization of L -lactide and ε-caprolactone
Chen, Hsuan-Ying,Lu, Wei-Yi,Chen, Yen-Jen,Hsu, Sodio C. N.,Ou, Siou-Wei,Peng, Wei-Te,Jheng, Nai-Yuan,Lai, Yi-Chun,Wu, Bo-Sheng,Chung, Hsuan,Chen, Yun,Huang, Ta-Chou
, p. 327 - 333 (2013/03/13)
This study synthesized a series of titanium iminophenoxide complexes and investigated their suitability as catalysts for the ring-opening polymerization of L-lactide (L-LA) and ε-caprolactone (CL). Complexes with bidentate ligands demonstrate higher catal
THERMAL DECOMPOSITION OF 2-HYDROXYBENZYLAMINES
Vinogradova, V. I.,Yunusov, M. S.
, p. 308 - 311 (2007/10/02)
The results are given of the preparation of a number of 2-hydroxybenzylamines and their thermal decomposition.The thermolysis reactions and the formation of the corresponding amines take place smoothly and with good yields.
Syntheses d'aminoalcools-1,3 ou d'aminophenols-1,3 par reduction d'enaminones ou d'iminophenols par les hydrures metalliques. Etude structurale par infrarouge et RMN des aminoalcools-1,3 bisecondaires diastereomeres
Maroni, Pierre,Cazaux, Louis,Tisnes, Pierre,Zambeti,Marianthie
, p. 179 - 186 (2007/10/02)
Enaminones, obtained by reaction of a primary amine with a β-diketone, can take three tautomeric forms: keto-enamine Ia, keto-imine Ib and imino-enol Ic.In general the keto-enamine form Ia is the most stable.Thi
N-Substituted Salicylaldimines Derivatives of Germanium(IV)
Singh, R. V.,Tandon, J. P.
, p. 1391 - 1398 (2007/10/02)
Hexa-coordinated Schiff base complexes of germanium of the general type Ge(OC2H5)2(SB)2 (SB(-) is the anion of the monofunctional bidentate Schiff base, SBH) have been synthesized by the reaction between ethyl-orthogermanate and the Schiff base in benzene
