29726-60-1Relevant academic research and scientific papers
Gold Particles Supported on Amino-Functionalized Silica Catalyze Transfer Hydrogenation of N-Heterocyclic Compounds
Vilhanová, Beáta,van Bokhoven, Jeroen A.,Ranocchiari, Marco
supporting information, p. 677 - 686 (2017/02/23)
In this work we demonstrate that exceptionally small gold particles (d=0.6±0.2 nm) supported on amino-functionalized mesoporous silicate SBA-15 are highly active in transfer hydrogenation of structurally diverse unsaturated N-heterocyclic compounds. The heterocyclic ring is reduced selectively. The gold particles aggregate to a diameter of 4–5 nm in the presence of formic acid/triethylamine (hydrogen donor) during the first catalytic run. In subsequent cycles the nanoparticles maintain their size, yielding a very stable catalytic system that was recycled more than five times. In contrast, analogous SBA catalysts featuring larger (～5–35 nm) gold particles are not active. Excess formic acid also leads to the formation of formamide derivatives of the products of hydrogenation, which can be deformylated quantitatively. Fifteen structurally different substrates, including the scaffolds of quinoline, isoquinoline, quinoxaline, acridine, phenanthroline, quinazoline, and phenanthridine are hydrogenated and deformylated to give the amine products in >90% overall yield. Deuterium labeling experiments indicate that 1,2-addition with subsequent disproportionation of the formed intermediate is the preferred reaction path over the 1,4-addition one, suggesting the participation of a gold hydride species. (Figure presented.).
Strong Br?nsted acid promoted asymmetric hydrogenation of isoquinolines and quinolines catalyzed by a Rh-thiourea chiral phosphine complex: Via anion binding
Wen, Jialin,Tan, Renchang,Liu, Shaodong,Zhao, Qingyang,Zhang, Xumu
, p. 3047 - 3051 (2016/05/19)
Rhodium catalyzed asymmetric hydrogenation of both isoquinolines and quinolines provides a new method to synthesize chiral tetrahydroisoquinolines and tetrahydroquinolines. By introducing strong Br?nsted acid HCl, anion binding between the substrate and t
NEW ISOINDOLINE OR ISOQUINOLINE COMPOUNDS, A PROCESS FOR THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
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Page/Page column 36, (2015/02/19)
Compounds of formula (I): (I) wherein Het, R3, R4, R5, R7, R8, R9, T, p, p', q, and q' are as defined in the description are pro-apoptotic agents useful in the treatment of cancers and of a
The remarkable effect of a simple ion: Iodide-promoted transfer hydrogenation of heteroaromatics
Wu, Jianjun,Wang, Chao,Tang, Weijun,Pettman, Alan,Xiao, Jianliang
supporting information; experimental part, p. 9525 - 9529 (2012/08/28)
I can do it! Accelerated by simple iodide ions, rhodium-catalysed transfer hydrogenation can be readily performed on quinolines, isoquinolines and quinoxalines, affording the tetrahydro products in high yields with low catalyst loading (see scheme). Copyright
Rare-earth-metal complexes supported by new chiral tetra-azane chelating ligands: Synthesis, characterization, and catalytic properties for intramolecular asymmetric hydroamination
Zhang, Yanyu,Yao, Wei,Li, He,Mu, Ying
experimental part, p. 4670 - 4679 (2012/10/08)
A number of new chiral tetra-azane proligands (1R,2R)-N,N′-bis(o- arylamino-benzylidene)-1,2-diaminocyclohexane ((1R,2R)-[(ArHN)C 6H4CH=N]2C6H10, Ar = 2,6-Me2C6H3 (L1H2), 2,6-Et2C6H3 (L2H2), 2,6-iPr2C6H3 (L3H 2)) have been synthesized via a nucleophilic displacement of the two fluorine atoms in (o-C6H4FCH=N)2C 6H10 with the lithium salt of the corresponding aniline derivative. Their rare-earth-metal complexes L1ScCl 2Li(THF)3 (1), L1YCl2Li(THF) 3 (2), L2YCl2Li(THF)3 (3), and L3YCl2Li(THF)2 (4) were synthesized in good yields via the salt metathesis of MCl3 (M = Sc, Y) with the dilithium salts of the ligands L1Li2(THF)4, L 2Li2(THF),4, and L3Li 2(THF)4, respectively. Further more, the two diethylamido complexes L1Y(NEt2)ClLi(THF)3 (5) and L 3Y(NEt2)ClLi(THF)2 (6) were also synthesized from reactions of the corresponding chloride complexes 2 and 4 with diethylamidolithium. The new proligands L1H2-L 3H2 and their rare-earth-metal complexes 1-6 have been characterized by elemental analyses and 1H and 13C NMR spectroscopy. The structures of complexes 1, 2, and 4 have been further confirmed by single-crystal X-ray diffraction analysis. The molecular structural analysis reveals that the metal centers in complexes 1, 2, and 4 acquire a distorted-octahedral coordination environment in their solid-state structures by sharing the chloride with a LiCl(THF)n moiety. After in situ treatment with nBuLi or Me3SiCH2Li, complexes 1-4 show reasonable catalytic activity and good enantioselectivity (up to 90%) for intramolecular asymmetric hydroamination reactions of terminal aminoalkenes. The amido complexes 5 and 6 can catalyze the intramolecular hydroamination reaction directly and show catalytic activities and enantioselectivities similar to those of the in situ formed alkyl complexes.
Impact of distinct chemical structures for the development of a methamphetamine vaccine
Moreno, Amira Y.,Mayorov, Alexander V.,Janda, Kim D.
supporting information; experimental part, p. 6587 - 6595 (2011/06/27)
(+)-Methamphetamine (METH) use and addiction has grown at alarming rates over the past two decades, while no approved pharmacotherapy exists for its treatment. Immunopharmacotherapy has the potential to offer relief through producing highly specific antibodies that prevent drug penetration across the blood-brain barrier thus decreasing reinforcement of the behavior. Current immunotherapy efforts against methamphetamine have focused on a single hapten structure, namely linker attachment at the aromatic ring of the METH molecule. Hapten design is largely responsible for immune recognition, as it affects presentation of the target antigen and thus the quality of the response. In the current paper we report the systematic generation of a series of haptens designed to target the most stable conformations of methamphetamine as determined by molecular modeling. On the basis of our previous studies with nicotine, we show that introduction of strategic molecular constraint is able to maximize immune recognition of the target structure as evidenced by higher antibody affinity. Vaccination of GIX+ mice with six unique METH immunoconjugates resulted in high antibody titers for three particularly promising formulations (45-108 μg/mL, after the second immunization) and high affinity (82, 130, and 169 nM for MH2, MH6, and MH7 hapten-based vaccines, respectively). These findings represent a unique approach to the design of new vaccines against methamphetamine abuse.
Intramolecular hydroamination of unbiased and functionalized primary aminoalkenes catalyzed by a rhodium aminophosphine complex
Julian, Lisa D.,Hartwig, John F.
supporting information; experimental part, p. 13813 - 13822 (2010/11/17)
We report a rhodium catalyst that exhibits high reactivity for the hydroamination of primary aminoalkenes that are unbiased toward cyclization and that possess functional groups incompatible with more electrophilic hydroamination catalysts. The rhodium catalyst contains an unusual diaminophosphine ligand (L1) that binds to rhodium in a K3-P,O,P mode. The reactions catalyzed by this complex typically proceed at mild temperatures (room temperature to 70 °C) and occur with primary aminoalkenes lacking substituents on the alkyl chain that bias the system toward cyclization, with primary aminoalkenes containing chloride, ester, ether, enolizable ketone, nitrile, and unprotected alcohol functionality, and with primary aminoalkenes containing internal olefins. Mechanistic data imply that these reactions occur with a turnover-limiting step that is different from that of reactions catalyzed by late-transition-metal complexes of Pd, Pt, and Ir. This change in the turnover-limiting step and resulting high activity of the catalyst stem from favorable relative rates for protonolysis of the M-C bond to release the hydroamination product versus reversion of the aminoalkyl intermediate to regenerate the acyclic precursor. Probes of the origin of the reactivity of the rhodium complex of L1 imply that the aminophosphine groups lead to these favorable rates by effects beyond steric demands and simple electron donation to the metal center.
Gold(I)-catalyzed intramolecular hydroamination of unactivated C=C bonds with alkyl ammonium salts
Bender, Christopher F.,Widenhoefer, Ross A.
supporting information; scheme or table, p. 2741 - 2743 (2009/02/04)
A mixture of (5)AuCl {5 = PCy2[2-(2,6-C6H 3(OMe)2)C6H4]} and AgOTf catalyzes the intramolecular hydroamination of unactivated C=C bonds with primary and secondary ammonium salts. The Royal
Indium metal as a reducing agent in organic synthesis
Pitts,Harrison,Moody
, p. 955 - 977 (2007/10/03)
The low first ionisation potential (5.8 eV) of indium coupled with its stability towards air and water, suggest that this metallic element should be a useful reducing agent for organic substrates. The use of indium metal for the reduction of C=N bonds in imines, the heterocyclic ring in benzo-fused nitrogen heterocycles, of oximes, nitro compounds and conjugated alkenes and the removal of 4-nitrobenzyl protecting groups is described. Thus the heterocyclic ring in quinolines, isoquinolines and quinoxalines is selectively reduced using indium metal in aqueous ethanolic ammonium chloride. Treatment of a range of aromatic nitro compounds under similar conditions results in selective reduction of the nitro groups; ester, nitrile, amide and halide substituents are unaffected. Likewise indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters. Indium is also an effective reducing agent under non-aqueous conditions and α-oximino carbonyl compounds can be selectively reduced to the corresponding N-protected amine with indium powder, acetic acid in THF in the presence of acetic anhydride or di-tert-butyl dicarbonate. Conjugated alkenes are also reduced by indium in THF-acetic acid.
A Chiral Synthesis of Four Stereoisomers of 1,3-Dimethyl-1,2,3,4-tetrahydroisoquinoline, an Inducer of Parkinson-like Syndrome
Toda, Jun,Matsumoto, Shinobu,Saitoh, Toshiaki,Sano, Takehiro
, p. 91 - 98 (2007/10/03)
Four stereoisomers of 1,3-dimethyl-1,2,3,4-tetrahydroisoquinoline, an inducer of Parkinson-like syndrome, were synthesized by applying a new method of 1,2,3,4-tetrahydroisoquinoline (TIQ) synthesis utilizing the Pummerer reaction as a key step. The chiral centers at C-1 and C-3 were constructed by two routes starting from alaninol (3) and 1-phenylethylamine (4) as a chiral source. Enantiomerically pure 1,3-dimethyl-TIQs (1R,3S)-(1), (1S,3R)-(ent-1), (1S,3S)-(2), and (1R,3R)-(ent-2) were prepared in a stereochemically unambiguous manner from 3 in 11 steps (route I) and from 4 in 6 steps (route II). The conformations of tetrahydroisoquinoline ring in 1-methyl, 3-methyl, and 1,3-dimethyl-TIQs were discussed on the basis of their CD, 1H-NMR spectra, and steric energies.
