- Synthesis of chiral salan ligands with bulky substituents and their application in Cu-catalyzed asymmetric Henry reaction
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Several new chiral N,N’-dimethylated salan ligands with bulky substituents were synthesized and their in-situ generated Cu(II) complexes were evaluated in the asymmetric Henry reaction. Substituents on the aryloxide moieties of these ligands were found to
- He, Jianghao,Mu, Ying,Wang, Zhou
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- Preparation method of (1R,2R)-(-)-N,N'-dimethyl-1,2-cyclohexanediamine
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The invention discloses a preparation method of (1R,2R)-(-)-N,N'-dimethyl-1,2-cyclohexanediamine. A methylation reaction of a cyclohexane compound represented by formula III and a methylation reagentis carried out in a solvent under the acation of an alkali to obtain a cyclohexane compound shown as a formula II. An amino group is protected through a benzoyl group, two methyl groups on the amino group can be avoided from being added at the same time, the methylation reaction condition is mild, benzoyl hydrolysis is easy, the danger that a large amount of lithium aluminum hydride is used is avoided, generation of solid waste is reduced, and environmental protection is facilitated. The method disclosed by the invention is low in cost, environment-friendly, high in reaction yield and suitablefor industrial safe mass production.
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Paragraph 0045-0046; 0049-0050
(2020/05/02)
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- Method for synthesizing trans-cyclohexanedimethanamine
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The invention discloses a method for synthesizing trans-cyclohexanedimethanamine, comprising steps of reacting cyclohexene oxide and methylamine aqueous solution under the catalysis of boric acid, and then adding sulfuric acid, dewatering to form an ester, ring-closing under alkaline conditions, adding methylamine aqueous solution and boric acid for hermetic reaction, and distilling to obtain trans-cyclohexanedimethanamine. The synthetic process is simple to perform, provides facilitated isolation and purification and high yield and product purity, and is suitable for batch production.
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Paragraph 0011; 0012; 0013; 0014; 0015; 0016; 0017; 0018
(2017/08/28)
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- An efficient synthesis of enantiomerically pure trans-N1,N 2-dimethylcyclohexane-1,2-diamine
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A new pathway is described to produce a highly optically pure isomer of trans-N1,N2-dimethylcyclohexane-1,2-diamine through four simple steps. Reaction of cyclohexene oxide with aqueous methylamine, followed by cyclisation with Mitsunobu reagent and ring-opening reactions gave rac-trans-N1,N2-dimethylcyclohexane-1,2-diamine, and the enantiomers were obtained via a kinetic resolution using tartaric acid.
- Shen, Yan-Hong,Ye, Qing,Hou, Shao-Gang,Wang, Qun
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p. 191 - 192
(2013/07/27)
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- Novel chiral bisformamide-promoted asymmetric allylation of benzaldehyde with allyltrichlorosilane
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Novel chiral bisformamides have been prepared from (R,R)-1,2- cyclohexanediamine and utilized as Lewis bases in the asymmetric allylation of benzaldehyde with allyltrichlorosilane. The reaction in the presence of Lewis base 1i gave an 83:17 enantiomeric r
- Ishimaru, Kaori,Ono, Kaori,Tanimura, Yuya,Kojima, Takakazu
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scheme or table
p. 3627 - 3634
(2011/10/09)
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- Synthesis and application of chiral N,N'-dialkylated cyclohexanediamine for asymmetric hydrogenation of aryl ketones
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Chiral N,N′-dialkylated cyclohexanediamine derived ligands have been synthesized and used in the asymmetric hydrogenation of aryl ketones. Optically active alcohols with up to 90% enantiomeric excess were obtained in high yields.
- Ma, Meng Lin,Ren, Chuan Hong,Lv, Ya Jing,Chen, Hua,Li, Xian Jun
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scheme or table
p. 155 - 158
(2012/01/03)
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- Chiral relay in NHC-mediated asymmetric β-lactam synthesis I; substituent effects in NHCs derived from (1R,2R)-cyclohexane-1,2-diamine
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The synthesis of a range of C2-symmetric imidazolinium salts from (1R,2R)-cyclohexane-1,2-diamine, and an evaluation of the reactivity and asymmetric induction of the derived NHCs as catalysts for the asymmetric synthesis of β-lactams, is reported. In this series, optimal enantioselectivity (up to 70% ee) is observed using N-benzyl or N-1-naphthylmethyl-substituted NHCs, consistent with a chiral relay effect operating to dictate the stereochemical outcome of this reaction.
- Duguet, Nicolas,Donaldson, Adele,Leckie, Stuart M.,Douglas, James,Shapland, Peter,Brown, Thomas B.,Churchill, Gwydion,Slawin, Alexandra M.Z.,Smith, Andrew D.
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experimental part
p. 582 - 600
(2010/08/19)
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- Enantioselective reduction of α-substituted ketones mediated by the boronate ester TarB-NO2
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A facile and mild reduction procedure is reported for the preparation of chiral secondary alcohols prepared from α-substituted ketones using sodium borohydride and the chiral boronate ester (l)-TarB-NO2. Direct reduction of substituted ketones bearing Lewis basic heteroatoms generally provided secondary alcohols of only modest enantiomeric excess likely due to either competition between the target carbonyl and the functionalized sidechains at the Lewis acidic boron atom in TarB-NO2 or the added steric bulk of the α-sidechain. As an alternative method, these substrates were synthesized using TarB-NO2 via a two-step procedure involving the reduction of an α-halo ketone to a chiral terminal epoxide, followed by regioselective/regiospecific epoxide opening by various nucleophiles. This procedure provides access to a variety of functionalized secondary alcohols including β-hydroxy ethers, thioethers, nitriles, and amines with enantiomeric excesses of 94% and yields up to 98%.
- Eagon, Scott,Ball-Jones, Nicholas,Haddenham, Dustin,Saavedra, Jaime,Delieto, Cassandra,Buckman, Matthew,Singaram, Bakthan
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supporting information; experimental part
p. 6418 - 6421
(2010/12/30)
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- On the two-ligand catalytic asymmetric deprotonation of N-Boc pyrrolidine: Probing the effect of the stoichiometric ligand
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(Chemical Equation Presented) To map out the stoichiometric ligand requirements in the two-ligand catalytic asymmetric deprotonation of N-Boc pyrrolidine, 24 different ligands have been evaluated; the highest enantioselectivity (90:10 er) was obtained by using s-BuLi in the presence of 0.3 equiv of (-)-sparteine and 1.3 equiv of a cyclohexanediamine-derived ligand.
- Bilke, Julia L.,O'Brien, Peter
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p. 6452 - 6454
(2008/12/21)
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- A new sparteine surrogate for asymmetric deprotonation of N-Boc pyrrolidine
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(Chemical Equation Presented) The s-BuLi complex of a cyclohexane-derived diamine is as efficient as s-BuLi/(-)-sparteine for the asymmetric deprotonation of N-Boc pyrrolidine. This is the first example of high enantioselectivity using a non-sparteine-like diamine in such reactions. The ( S, S)-diamine is a useful (+)-sparteine surrogate and was utilized in short syntheses of (-)-indolizidine 167B and an intermediate for the synthesis of the CCK antagonist (+)-RP 66803.
- Stead, Darren,O'Brien, Peter,Sanderson, Adam
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supporting information; experimental part
p. 1409 - 1412
(2009/04/12)
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- Spiroborate esters in the borane-mediated asymmetric synthesis of pyridyl and related heterocyclic alcohols
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The effectiveness of several spiroborate ester catalysts was investigated in the asymmetric borane reduction of 2-, 3-, and 4-acetylpyridines under different reaction conditions. Highly enantiomerically enriched 1-(2-, 3-, and 4-pyridyl)ethanols and 1-(heterocyclic)ethanols were obtained using 1-10% catalytic loads of the spiroborate 5 derived from diphenylprolinol and ethylene glycol.
- Stepanenko, Viatcheslav,De Jesus, Melvin,Correa, Wildeliz,Guzman, Irisbel,Vazquez, Cindybeth,Ortiz, Lymaris,Ortiz-Marciales, Margarita
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p. 2738 - 2745
(2008/03/27)
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- The role of chelating diamine ligands in the Goldberg reaction: A kinetic study on the copper-catalyzed amidation of aryl iodides
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The mechanistic details of the Cu-catalyzed amidation of aryl iodides are presented. The kinetic data suggest that the diamine ligand prevents multiple ligation of the amide. The formation of an amidocuprate species external to the catalytic cycle helped to rationalize the dependence on diamine concentration and the inverse dependence on amide concentration at low diamine concentrations. The intermediacy of a Cu(I) amidate was established through both its chemical and kinetic competency. Copyright
- Strieter, Eric R.,Blackmond, Donna G.,Buchwald, Stephen L.
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p. 4120 - 4121
(2007/10/03)
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- Asymmetric allyl- and crotylboration with the robust, versatile, and recyclable 10-TMS-9-borabicyclo[3.3.2]decanes
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The remarkable versatility and selectivity of the 10-(trimethylsilyl)-9- borabicyclo[3.3.2]decanes (10-TMS-9-BBDs) in the allyl- and crotylboration of representative aldehydes are reported. The new reagents are prepared through air-stable crystalline pseudoephedrine borinic ester complexes of the 10-TMS-9-BBDs (4), which are available in 63% overall yield from B-MeO-9-BBN through a simple two-step procedure. These complexes 4 are directly converted to the corresponding B-allyl-10-TMS-9-BBDs (1) with allylmagnesium bromide, which either can be isolated (98%) or used in situ for the allylations. The remarkable enantioselectivity (96 to ≥99% ee) of these reagents in the rapid (3 h), asymmetric allylboration process at -78 °C is only slightly diminished when it is conducted at 25 °C, a phenomenon attributable to its rigid bicyclic structure. In addition to providing the homoallylic alcohols 6 efficiently (68-80%), the procedure also permits the efficient recovery of 4 (68-84%) for the direct regeneration of 1. Alternatively, an oxidative workup procedure can be used for the preparation of 6. The reagent gives predictable stereochemistry and exhibits an extremely high level of reagent control in the allylboration of D-glyceraldehyde acetonide. A simple and efficient procedure has been developed for the preparation of all four geometric and enantiomeric isomers of the B-crotyl-10-TMS-9-BBDs (10) from optically pure enantiomers of B-MeO-10-TMS-9-BBD (3). These reagents 10 also add rapidly (3 h) and efficiently to representative aldehydes at -78 °C, providing ready access to all four of the possible stereoisomers of the β-methyl homoallylic alcohols 12-15 (69-92%) in high dr (≥98:2) and ee (94-99%).
- Burgos, Carlos H.,Canales, Eda,Matos, Karl,Soderquist, John A.
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p. 8044 - 8049
(2007/10/03)
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- An efficient synthesis of tetrasubstituted cyclohexyl-1,2-diamines
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The synthesis of symmetrically tetrasubstituted diamines derived from the (R,R)-cyclohexyl-1,2-diamine is reported. We comment on the efficiency of this sequential substitution approach as a method for the synthesis of tetrasubstituted diamines and discus
- Arjan, Hitesh,Boyd, Ewan,Coumbarides, Gregory S.,Eames, Jason,Jones, Ray V. H.,Stenson, Rachel A.,Suggate, Michael J.
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p. 1921 - 1925
(2007/10/03)
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- Synthesis, resolution, and application of 2,2′-bis(diphenylphosphino) -3,3′-binaphtho[b]furan (BINAPFu)
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(±)-2,2′-Bis(diphenylphosphino)-3,3′-binaphtho[2,1-b] furan (BINAPFu) was synthesized from 2-naphthoxyacetic acid in a five-step sequence in 62% overall yield. A variety of reported resolution procedures for biaryl bisphosphines did not work with (±)-BINAPFu; thus, a new resolution method was developed, involving the Staudinger reaction of the aforementioned racemate of BINAPFu with an enantiopure camphor sulfonyl azide derivative. The resulting diastereomeric phosphinimines were separated by flash chromatography. Subsequent hydrolysis to the corresponding bis-phosphine oxide and trichlorosilane reduction provided enantiopure BINAPFu. The absolute stereochemical configuration of BINAPFu was established by X-ray crystallography. BINAPFu was compared with commercially available 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (BINAP) in Pd(0)-catalyzed intermolecular Heck reactions. Investigation of the Heck arylation of 2,3-dihydrofuran showed BINAPFu to be more efficacious than BINAP in dioxane at 30°C. A variety of phosphorus selenides were prepared, and the 1JP-Se coupling constants measured, to obtain a comparative scale of parent phosphine basicity. The phosphorus atoms in BINAPFu were found to be electron deficient when compared with BINAP but slightly more electron rich than trifurylphosphine.
- Andersen, Nell G.,Parvez, Masood,McDonald, Robert,Keay, Brian A.
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p. 145 - 161
(2007/10/03)
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- New enantioselective chiral imidazolidine ligands for Pd-catalyzed asymmetric allylic alkylation
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Chiral imidazolidine ligands have been synthesized from N,N′-dialkylated cyclohexanediamine derivatives and they were found to act as effective ligands in the palladium-catalyzed asymmetric allylic substitution. The excellent levels of enantiomeric excess up to 98% were obtained in high yield.
- Lee, En-Kyung,Kim, Sang-Han,Jung,Ahn, Wha-Seung,Kim, Geon-Joong
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p. 1971 - 1974
(2007/10/03)
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- The copper-catalyzed N-arylation of indoles
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A general method for the N-arylation of indoles using catalysts derived from Cul and trans-1,2-cyclohexanediamine (1a), trans-N,N′-dimethyl-1,2-cyclohexanediamine (2a), or N,N′-dimethyl-ethylenediamine (3) is reported. N-Arylindoles can be produced in high yield from the coupling of an aryl iodide or aryl bromide with a variety of indoles.
- Antilla, Jon C.,Klapars, Artis,Buchwald, Stephen L.
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p. 11684 - 11688
(2007/10/03)
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- N,N'-dialkylated 1,2-diamine derivatives as new efficient ligands for RuCl2(PPh3)3 catalyzed asymmetric transfer hydrogenation of aromatic ketones
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Chiral N,N'-dialkylated cyclohexanediamine derivatives ligands have been synthesized and used in an asymmetric transfer hydrogenation of aryl ketones. Optically active alcohols with up to 93% enantiomeric excess were obtained in high yield.
- Kim, Geon-Joong,Kim, Sang-Han,Chong, Pong-Hyun,Kwon, Mi-Ae
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p. 8059 - 8062
(2007/10/03)
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- An efficient method for the synthesis of N,N′-dimethyl-1,2-diamines
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A simple method for the preparation of N,N′-dimethyl-1,2-diamines is described. The method requires the dimethylation of a diazaphospholidine oxide followed by acid-catalysed hydrolysis.
- Tye, Heather,Eldred, Colin,Wills, Martin
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p. 155 - 158
(2007/10/03)
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- A practical and efficient synthesis of chiral N,N-disubstituted C2 symmetric diamines derived from (R,R)-1,2-diaminocyclohexane
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An improved synthesis of chiral diamine ligands derived from (R,R)-1,2-diaminocyclohexane is described, providing N-substituted diamines. The synthesis of other new ligands based on this methodology is also reported.
- Alexakis, Alexandre,Chauvin, Anne-Sophie,Stouvenel, Ricardo,Vrancken, Emmanuel,Mutti, Stephane,Mangeney, Pierre
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p. 1171 - 1178
(2007/10/03)
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- The asymmetric synthesis of α-substituted α-methyl and α-phenyl phosphonic acids: Design, carbanion geometry, reactivity and preparative aspects of chiral alkyl bicyclic phosphonamides
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The design, preparation, structural and spectroscopic analyses of topologically unique and enantiomerically pure alkyl phosphonamides are described. In the case of α-ethyl and α-benzyl phosphonamides, the geometry of both the secondary and tertiary carbanions was determined to be planar through deprotonation/deuteration/alkylation experiments. Stereoselective alkylations of such systems proceeded in good yields and with high diastereoselectivities. The resulting α,α-alkylated phosphonamides were hydrolyzed to give the corresponding α,α-alkyl phosphonic acids with high degrees of enantiomeric purity.
- Bennani, Youssef L.,Hanessian, Stephen
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p. 13837 - 13866
(2007/10/03)
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- Synthesis and characterization of both enantiomers of a chiral C60 derivative with C2 symmetry
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The addition of chiral diamines to C60 allows the synthesis of the two enantiomers of a chiral C60 derivative with C2 symmetry. The circular dichroism spectra of the two isomers show a very intense chirospectroscopic response.
- Maggini,Scorrano,Bianco,Toniolo,Prato
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p. 2845 - 2846
(2007/10/02)
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- A New Reagent for the Determination of the Optical Purity of Primary, Secondary, and Tertiary Chiral Alcohols and of Thiols
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A new reagent is described for the determination of the enantiomeric excess of chiral alcohols.This derivatizing agent (22) is a diazaphospholidine, easily prepared from hexamethylphosphorus triamide (HMPT) and a chiral diamine having a C2 axis
- Alexakis, Alexandre,Mutti, Stephane,Mangeney, Pierre
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p. 1224 - 1231
(2007/10/02)
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- A NEW REAGENT FOR A VERY SIMPLE AND EFFICIENT DETERMINATION OF ENANTIOMERIC PURITY OF ALCOHOLS BY 31P NMR
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A new reagent is described for the determination of enantiomeric excess of chiral alcohols.This derivatizing agent allows an accurate analysis by 31P NMR.A large array of primary, secondary, and tertiary alcohols, functionalized or not, were successfully
- Alexakis, Alexandre,Mutti, Stephane,Normant, Jean F.,Mangeney, Pierre
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p. 437 - 440
(2007/10/02)
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- 211. Scope and Limitations of the Reductive Coupling of Aromatic Aldimine Derivatives with Formation of 1,2-Diarylethylenediamine Units, Using Low-Valent Titanium Reagents
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Besides the adducts from lithium amides to aromatic aldehydes, iminium salts, aminals, and N-silylimines of aromatic aldehydes are coupled by the black suspension obtained from TiCl4 and Mg turnings in tetrahydrofuran (THF).The 1,2-diarylethylenediamines with tertiary and primary amino groups thus obtained are formed with no or only moderate diastereoselectivity (products 4a-d (Scheme 2) and 5a-e (Scheme 3), respectively); the amine component may contain a strained ring or additional heteroatoms as in azetidin, bis(2-metoxyethyl)amine piperazine, morpholine, and thiomorpholine (products 6a-e; Table 1).By an in-situ procedure, ethylenediamines and propane-1,3-diamines with two secondary amino groups are cyclized with aromatic aldehydes to give exclusively trans-diaryl-substituted piperazine and perhydro-1,4-diazepine derivatives (products 7a-f; Table 2).Enantiomerically pure monocyclic trans,cis-5-alkyl-2,3-diaryl-piperazines and diazabicyclononanes and -decanes are obtained by employing suitable diamines prepared from the amino acids (S)-alanine, (S)-phenylalanine, (S)-proline, and from (S,S)- or (R,R)-cyclohexane-1,2-diamine, respectively (products 11a-i, 7e; Table 4).The configurations of all products are derived from the high-field NMR spectra, some of which are discussed in detail (Figs. 1 and 2, Tables 3 and 5); all new compounds are fully characterized by their physical data.Depending upon the structure of the components employed, the yields of purified products range from as low as 7percent to essentially quantitative.
- Betschart, Claudia,Schmidt, Beat,Seebach, Dieter
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p. 1999 - 2021
(2007/10/02)
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- Use of Carboxylic Acids as Chiral Solvating Agents for the Determination of Optical Purity of Chiral Amines by NMR Spectroscopy
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Optically pure mandelic acid, Mosher's acid, and N-(3,5-dinitrobenzoyl)phenylglycine have been used as chiral solvating agents to induce nonequivalence in the 1H NMR spectra of several diamines, amino acid esters, amino alcohols, and other amines.The identity of the chiral solvating agent and the stoichiometry of the solvation complexes that yield the greatest nonequivalence varies with the nature of the substrate.
- Benson, Scott C.,Cai, Ping,Colon, Marcelo,Haiza, Mohammed A.,Tokles, Maritherese,Snyder, John K.
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p. 5335 - 5341
(2007/10/02)
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- SUBSTITUTED NAPHTHALENYLOXY-1,2-DIAMINOCYCLOHEXYL AMIDE COMPOUNDS
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Substituted naphthalenyloxy-or naphthalenylthiooxyamides of trans-1,2-diaminocyclohexanes possess selective kappa opioid receptor site binding activity and are thus useful as analgesic or diuretic agents. Methods of preparing the compounds, pharmaceutical compositions, and a method for their use as analgesic agents are also disclosed.
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- Substituted trans-1,2-diaminocyclohexyl amide compounds
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Substituted trans-1,2-diaminocyclohexyl amide compounds demonstrating selective opioid receptor binding possess utility as analgesic, diuretic, and psychotherapeutic agents. A method of preparing the compounds, pharmaceutical compositions employing the compounds, and a method of alleviating pain employing the compounds are also disclosed.
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- Chiral Recognition in Catalytic Hydrogenation of α-Acylaminoacrylic Acids by Cationic Rhodium(I) Complexes of Chiral Aminophosphines Derived from (R,R)-1,2-Cyclohexanediamine or (R)-1,2-Propanediamine
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Four chiral diphosphines, (R,R)-1,2-biscyclohexane, (R,R)-1,2-bis-cyclohexane, (R)-1,2-bispropane, and (R)-1,2-bispropane have been prepared from the corresponding optically active diamines.The cationic 1,5-cyclooctadiene rhodium(I) complexes with these diphosphines act as effective homogeneous catalysts for the stereoselective hydrogenation of α-acylaminoacrylic acids.The optical yields and the absolute configurations of the products depend on the kind of diphosphine ligands.The (R,R)-1,2-biscyclohexane complex catalyst yields N-benzoyl-(S)-leucine, N-benzoyl-(S)-phenylalanine, and N-acetyl-(S)-phenylalanine in 94, 92, and 89percent e.e., respectively.The other three catalysts are less effective (6-74percent e.e.).The aminophosphine complexes with methyl groups on the nitrogen atoms always give (S)-amino acids, those with no methyl group (R)-amino acids.Such a difference in the chiral recognition has been discussed on the basis of circular dichroism spectra and Dreiding molecular models of the rhodium (I) complexes.
- Kashiwabara, Kazuo,Hanaki, Kazuhiro,Fujita, Junnosuke
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p. 2275 - 2280
(2007/10/02)
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