Ligands amine derivatives

Helmchen and coworkers employed a,co-amino-1,3-dienes as substrates [51]. By using palladium complexes with chiral phosphino-oxazolines L as catalysts, an enantiomeric excess of up to 80 % was achieved. In a typical experiment, a suspension of Pd(OAc)2, the chiral ligand L, the aminodiene 6/1-90 and an aryltriflate in dimethylformamide (DMF) was heated at 100 °C for 10 days. Via the chiral palladium complex 6/1-91, the resulting cyclic amine derivative 6/1-92 was obtained in 47% yield and 80% ee (Scheme 6/1.23). Using aryliodides the reaction time is shorter, and the yield higher (61 %), but the enantiomeric excess is lower (67% ee). With BINAP as a chiral ligand for the Pd°-catalyzed transformation of 6/1-90 and aryliodide, an ee-value of only 12% was obtained. 

A variety of ligands were used to hydrogenate 73a, 74a-b, 75a-b, and 76a with moderate results. Steric interactions were magnified and that may explain why nearly all of the substrates in Scheme 15 give less than optimal results. A-methyl-A-phenyl-amine derived enamines 74a and 75a were resistant to hydrogenation where the analogous A-methyl-W-benzyl-amine-based enamines were completely converted with SimplePHOX ligand 77 with moderate enantioselectivity. 

BIS(TERT-BUTYLMETHYLPHOSPfflNO)QUINOXALINE (QuinoXP ) AS A LIGAND FOR RHODIUM-CATALYZED ASYMMETRIC HYDROGENATION OF PROCHIRAL AMINO ACID AND AMINE DERIVATIVES... 

The reaction of carbonyl sulfide with [M(02)(PPh3)2] (where M = Pd or Pt) has resulted in the first reported examples of transition metal complexes of the monothiocarbonate anion (47 R = O-). Bidentate S—O coordination was concluded from 3IP H NMR analyses of these compounds.184 A short structural review of metal complexes of monothiocarbamate ions (47 R = N(R )R") demonstrates their varied coordination chemistry.185 In complexes of the dialkyl forms the sulfur atom is seen to have considerable mercaptide character , whereas aromatic amine derivatives demonstrate C—S and M—S partial multiple bonding.185,251 A review on the coordination chemistry of these ligands has appeared.186 Additional detail is provided in Chapter 16.4 of this volume. 

Unlike ethylene glycol, a-hydroxycarboxylic acids, and p-mercaptoethanol, ligands such as ethanolamine, ethylenediamine, amino acids, and 2-aminoethanethiol do not form V2L2 complexes with vanadate [46], However, weakly formed products of VL stoichiometry (—546 ppm, —556 ppm) are observed with a number of a-amino acids [47], Because the amine functionality in amino acids is not suitable for formation of the cyclic [VN]2 core expected for a dimer, then one or the other of these VL compounds may correspond to the monomeric precursor to such a dimeric product. Certainly, with the a-hydroxycarboxylic acids, the monomeric complex can be a major component in solution. Similar VL complexes have not been reported for the amino alcohols. Perusal of the available reports suggests that the amine derivatives were studied under conditions where the nitrogen functionality was protonated, so the results may be somewhat misleading. 

Kinetics studies carried out in acetonitrile solutions provided a similar picture for the mechanism of peroxidation. Studies were carried out for three related tertiary amine-derived ligands /V,/V-bis(2-pyridylmcthyl)glycinc, /V-(2-pyridylmcthyl)imin-odiacetic acid, and AK2-amidomethyl [iminodiacetic acid [14], The kinetics studies... 

Complexes with aromatic amine derivative-type ligands 182... 

This class of ligands mostly consists of derivatives of pyridine, 2.2 -bipyridinc. 2,2, 2"-ter-pyridine, and 1,10-phenanthroline. Scheme 6 shows the structures of fourEu3+ chelates with aromatic amine derived ligands, that can be covalently bound to proteins, for time-resolved fluorometry, among which 4,7-bis(chlorosulfophenyl)-l,10-phenanthroline-2,9-dicarboxylic acid (BCPDA)-Eu3+ and trisbipyridine cryptate (TBP)-Eu3+ are widely used for europium fluorescence labels in TR-FIA. 

Markus Albrecht and co-workers synthesised three M4L4 tetrahedra based on different C3-symmetric imine type ligands. The ligands are shown in Fig. 16. For the formation of these ligands, 2,3-dihydroxybenzaldehyde was reacted with the product of the reduction of the corresponding trinitro derivative (L21) or with a tris-amine derivative (L22, L23) [30, 135-141]. 

Chiral Ligand of L1A1H4 for the Enantioselective Reduction of Alkyl Phenyl Ketones. Optically active alcohols are important synthetic intermediates. There are two major chemical methods for synthesizing optically active alcohols from carbonyl compounds. One is asymmetric (enantioselective) reduction of ketones. The other is asymmetric (enantioselective) alkylation of aldehydes. Extensive attempts have been reported to modify Lithium Aluminum Hydride with chiral ligands in order to achieve enantioselective reduction of ketones. However, most of the chiral ligands used for the modification of LiAlHq are unidentate or bidentate, such as alcohol, phenol, amino alcohol, or amine derivatives. 

After the demonstration of THC binding sites in the CNS (26), a search for an endogenous ligand produced the long-chain ethanol-amine derivative (17) of arachidonic acid, known as anandamide (27). Subsequently, the glycerol ester of arachidonic acid (18), known as 2-AG, was shown to be a more abundant endogenous ligand in the brain than anandamide (28). Further development has tended... 

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