- Rh(III)-catalyzed synthesis of isoquinolines using the N-Cl bond of N-chloroimines as an internal oxidant
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The Rh(III)-catalyzed coupling of N-chloroimines with alkynes for the efficient synthesis of isoquinolines is reported. This represents the first use of the N-Cl bond of N-chloroimines as an internal oxidant for construction of the isoquinoline skeleton. The synthesis features atom and step economy, a green solvent (EtOH), mild reaction conditions, and a broad substrate scope.
- Chu, Benfa,Fang, Lili,Guo, Shan,Qi, Bing,Shi, Pengfei,Wang, Qi,Zhu, Jin
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supporting information
(2020/03/10)
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- The Synthesis of Primary Amines through Reductive Amination Employing an Iron Catalyst
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The reductive amination of ketones and aldehydes by ammonia is a highly attractive method for the synthesis of primary amines. The use of catalysts, especially reusable catalysts, based on earth-abundant metals is similarly appealing. Here, the iron-catalyzed synthesis of primary amines through reductive amination was realized. A broad scope and a very good tolerance of functional groups were observed. Ketones, including purely aliphatic ones, aryl–alkyl, dialkyl, and heterocyclic, as well as aldehydes could be converted smoothly into their corresponding primary amines. In addition, the amination of pharmaceuticals, bioactive compounds, and natural products was demonstrated. Many functional groups, such as hydroxy, methoxy, dioxol, sulfonyl, and boronate ester substituents, were tolerated. The catalyst is easy to handle, selective, and reusable and ammonia dissolved in water could be employed as the nitrogen source. The key is the use of a specific Fe complex for the catalyst synthesis and an N-doped SiC material as catalyst support.
- B?umler, Christoph,Bauer, Christof,Kempe, Rhett
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p. 3110 - 3114
(2020/06/01)
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- Rh(III)-Catalyzed Coupling of N-Chloroimines with α-Diazo-α-phosphonoacetates for the Synthesis of 2 H-Isoindoles
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We report herein the first use of N-chloroimines as effective synthons for directed C-H functionalization. Rh(III)-catalyzed coupling of N-chloroimines with α-diazo-α-phosphonoacetates allows for efficient dechlorinative/dephosphonative access to 2H-isoindoles. Further deesterification under Ni(II) catalysis enables the complete elimination of reactivity-assisting groups and full exposure of reactivity of C3 and N2 ring atoms for attaching structurally distinct appendages.
- Qi, Bing,Li, Lei,Wang, Qi,Zhang, Wenjing,Fang, Lili,Zhu, Jin
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supporting information
p. 6860 - 6863
(2019/09/12)
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- METHOD FOR THE HOMOGENEOUS CATALYTIC REDUCTIVE AMINATION OF CARBONYL COMPOUNDS
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The present invention relates to a method for the reductive amination of a carbonyl compound, comprising one or more carbonyl groups amenable to reductive amination, forming the corresponding primary amine, characterized in that the reaction is carried out in the presence of a homogeneously dissolved catalyst complex K, comprising at least one metal atom from Group 8, 9 or 10 of the periodic table, bearing a bidentate phosphane ligand, a carbonyl ligand, a neutral ligand and a hydride ligand, and also an acid as co-catalyst.
- -
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Paragraph 0212; 0219-0221
(2018/07/29)
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- N-Alkylation of Aqueous Ammonia with Alcohols Leading to Primary Amines Catalyzed by Water-Soluble N-Heterocyclic Carbene Complexes of Iridium
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A new catalytic system for the N-monoalkylation of aqueous ammonia with a variety of alcohols was developed. Water-soluble dicationic complexes of iridium bearing N-heterocyclic carbene and diammine ligands exhibited high catalytic activity for this type of reaction on the basis of hydrogen-transfer processes without generating harmful or wasteful byproducts. Various primary amines were efficiently synthesized by using safe, inexpensive, and easily handled aqueous ammonia as a nitrogen source. For example, the reaction of 1-(4-methylphenyl)ethanol with aqueous ammonia in the presence of a water-soluble N-heterocyclic carbene complex of iridium at 150 °C for 40 h gave 1-(4-methylphenyl)ethylamine in 83 % yield.
- Fujita, Ken-Ichi,Furukawa, Shohichi,Morishima, Namino,Shimizu, Mineyuki,Yamaguchi, Ryohei
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p. 1993 - 1997
(2018/03/13)
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- Substituent effects on chiral resolutions of derivatized 1-phenylalkylamines by heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin GC stationary phase
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Chiral resolutions of trifluoroacetyl-derivatized 1-phenylalkylamines with different type and position of substituent were investigated by capillary gas chromatography by using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin diluted in OV-1701 as a chiral stationary phase. The influence of column temperature on retention and enantioselectivity was examined. All enantiomers of meta-substituted analytes as well as fluoro-substituted analytes could be resolved. Temperature had a favorable influence on enantioselectivity for small amines with substituents at the ortho-position. The type of substituent at the stereogenic center of amines also had a crucial effect as the ethyl group led to poor enantioseparation. Among all analytes studied, trifluoroacetyl-derivatized 1-(2′-fluorophenyl)ethylamine exhibited baseline resolution with the shortest analysis time.
- Issaraseriruk, Natthapol,Sritana-anant, Yongsak,Shitangkoon, Aroonsiri
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supporting information
p. 900 - 906
(2018/05/08)
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- Stereoselective amination of racemic sec-alcohols through sequential application of laccases and transaminases
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A one-pot/two-step bienzymatic asymmetric amination of secondary alcohols is disclosed. The approach is based on a sequential strategy involving the use of a laccase/TEMPO catalytic system for the oxidation of alcohols into ketone intermediates, and their following transformation into optically enriched amines by using transaminases. Individual optimizations of the oxidation and biotransamination reactions have been carried out, studying later their applicability in a concurrent process. Therefore, 17 racemic (hetero) aromatic sec-alcohols with different substitutions in the aromatic ring have been converted into enantioenriched amines with good to excellent selectivities (90-99% ee) and conversion values (67-99%). The scalability of the process was also demonstrated when two different amine donors were used in the transamination step, such as isopropylamine and cis-2-buten-1,4-diamine. Satisfyingly, both sacrificial amine donors can shift the equilibrium toward the amine formation, leading to the corresponding isolated enantioenriched amines with good to excellent results.
- Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
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p. 474 - 480
(2017/06/23)
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- Asymmetric Biocatalytic Synthesis of Fluorinated Pyridines through Transesterification or Transamination: Computational Insights into the Reactivity of Transaminases
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The synthesis of a family of pyridines bearing a fluorinated substituent on the aromatic ring has been carried out through two independent and highly stereoselective chemoenzymatic strategies. Short chemical synthetic routes toward fluorinated racemic amines and prochiral ketones have been developed, which served as substrates to explore the suitability of lipases and transaminases in asymmetric biotransformations. The lipase-catalyzed kinetic resolution via acylation of racemic amines proceeded smoothly giving conversions close to 50% and excellent enantioselectivities. Alternatively, the biotransamination of the corresponding prochiral ketones was investigated giving access to both optically pure amine enantiomers using transaminases with complementary selectivity. High to quantitative conversion values were achieved, which allowed the isolation of the amines in moderate to high yields (40–88%). A deeper understanding of the latter process was enabled by performing theoretical calculations on thermodynamic and mechanistic aspects. Calculations showed that the biotransamination reactions are highly favoured by the presence of fluorine atoms and the pyridine ring. (Figure presented.).
- López-Iglesias, María,González-Martínez, Daniel,Rodríguez-Mata, María,Gotor, Vicente,Busto, Eduardo,Kroutil, Wolfgang,Gotor-Fernández, Vicente
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supporting information
p. 279 - 291
(2017/02/05)
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- Versatile Dynamic Covalent Assemblies for Probing π-Stacking and Chirality Induction from Homotopic Faces
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Herein we report for the first time the use of dynamic covalent reactions (DCRs) for building a π-stacking model system and further quantifying its substituent effects (SEs), which remain a topic of debate despite the rich history of stacking. A general DCR between 10-methylacridinium ion and primary amines was discovered, in which π-stacking played a stabilizing role. Facile quantification of SEs with in situ competing π-stacking systems was next achieved in the form of amine exchange exhibiting structural diversity by simply varying components. The linear correlation with σm in Hammett plots indicates the dominance of purely electrostatic SEs, and the additivity of SEs is in line with the direct interaction model. With α-chiral amines π-stacking within the adduct enabled chirality transfer from homotopic faces. The strategy of dynamic covalent assembly should be appealing to future research of probing weak interactions and manipulating chirality.
- Ye, Hebo,Hai, Yu,Ren, Yulong,You, Lei
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supporting information
p. 3804 - 3809
(2017/03/27)
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- Trading N and O. Part 3: Synthesis of 1,2,3,4-tetrahydroisoquinolines from α-hydroxy-β-amino esters
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A range of enantiopure 1,2,3,4-tetrahydroisoquinolines have been prepared directly from α-hydroxy-β-amino esters. Activation of the α-hydroxy group upon treatment with Tf2O and 2,6-di-tert-butyl-4-methylpyridine promotes aziridinium formation,
- Davies, Stephen G.,Fletcher, Ai M.,Frost, Aileen B.,Kennedy, Matthew S.,Roberts, Paul M.,Thomson, James E.
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p. 2139 - 2163
(2016/04/09)
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- Direct Synthesis of Primary Amines via Ruthenium-Catalysed Amination of Ketones with Ammonia and Hydrogen
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A highly selective reductive amination of ketones to primary amines with ammonia and hydrogen using a simple ruthenium catalyst has been developed. The protocol described constitutes an efficient and direct atom-economical approach en route to α-methylbenzylamine derivatives in good to high yields. The presence of catalytic amounts of aluminum triflate turned out to be crucial for achieving high conversion towards primary amines.
- Gallardo-Donaire, Joan,Ernst, Martin,Trapp, Oliver,Schaub, Thomas
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supporting information
p. 358 - 363
(2016/04/26)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 0314; 0321
(2015/03/28)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formula: (Formula (I)) where ring B is a conjugated ring system with one or more substituents. The catalysts of the invention are particularly effective in reductive amination procedures which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 0297; 0303
(2015/03/16)
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- Primary amines by transfer hydrogenative reductive amination of ketones by using cyclometalated IrIII catalysts
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Cyclometalated iridium complexes are found to be versatile catalysts for the direct reductive amination (DRA) of carbonyls to give primary amines under transfer-hydrogenation conditions with ammonium formate as both the nitrogen and hydrogen source. These complexes are easy to synthesise and their ligands can be easily tuned. The activity and chemoselectivity of the catalyst towards primary amines is excellent, with a substrate to catalyst ratio (S/C) of 1000 being feasible. Both aromatic and aliphatic primary amines were obtained in high yields. Moreover, a first example of homogeneously catalysed transfer-hydrogenative DRA has been realised for β-keto ethers, leading to the corresponding β-amino ethers. In addition, non-natural α-amino acids could also be obtained in excellent yields with this method. Reduce the work! A broad range of ketones have been successfully aminated to afford primary amines under transfer-hydrogenation conditions by using ammonium formate as the amine source and 0.1 mol % of a cyclometalated IrIII catalyst (see scheme). Copyright
- Talwar, Dinesh,Salguero, Noemi Poyatos,Robertson, Craig M.,Xiao, Jianliang
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supporting information
p. 245 - 252
(2014/01/17)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 00163; 00170
(2013/11/05)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formula: (Formula (I)) where ring B is a conjugated ring system with one or more substituents. The catalysts of the invention are particularly effective in reductive amination procedures which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 00141; 00145; 00147
(2013/11/05)
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- Synthesis and in vitro EGFR (ErbB1) tyrosine kinase inhibitory activity of 4-N-substituted 6-aryl-7H-pyrrolo[2,3-d]pyrimidine-4-amines
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A series of 4-N-substituted 6-aryl-7H-pyrrolo[2,3-d]pyrimidine-4-amines have been synthesised, characterised and tested for their in vitro EGFR (ErbB1) tyrosine kinase inhibitory activity. The compounds were prepared from ethyl cyanoacetate and α-bromoacetophenones via the 2-amino-3-ethoxycarbonyl-5- aryl-pyrroles and 4-chloro-6-arylpyrrolopyrimidines. Aromatic substitution with benzylic amines was performed by conventional thermal substitution, and palladium catalysed coupling. The two methods resulted in similar yields, but the palladium coupling had the benefit of lower chemical consumption and reduced reaction times. Eight of the new compounds had IC50 values in the range of 2.8-9.0 nM. Four of these have a fluorine atom positioned at sites otherwise potentially susceptible to oxidative metabolism. Structural variation of the 6-aryl group indicated that the inhibitory action was only moderately sensitive to modifications in this fragment. However, the potency depended strongly on the structure of the aromatic part of the 4-amino group, and any aromatic substitution except fluorine reduced the in vitro activity. The cellular EGFR internalization response of selected compounds was evaluated using HeLa cells. Three fluorinated derivatives had a pronounced effect in inhibiting EGFR internalization.
- Kaspersen, Svein Jacob,Sorum, Christopher,Willassen, Veronica,Fuglseth, Erik,Kjobli, Eli,Bjorkoy, Geir,Sundby, Eirik,Hoff, Brd Helge
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experimental part
p. 6002 - 6014
(2012/01/02)
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- Asymmetric synthesis of chiral primary amines by transfer hydrogenation of N -(tert -Butanesulfinyl)ketimines
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(Figure presented) The diastereoselective reduction of (R)-N-(tert- butanesulfinyl)ketimines by a ruthenium-catalyzed asymmetric transfer hydrogenation process in isopropyl alcohol, followed by desulfinylation of the nitrogen atom, is an excellent method to prepare highly enantiomerically enriched α-branched primary amines (up to >99% ee) in short reaction times (1-4 h). (1S,2R)-1-Amino-2-indanol has been shown to be a very efficient ligand to perform this transformation. Ketimines bearing either an aryl or a heteroaryl group and an alkyl group as substituents of the iminic carbon atom are very good substrates for this process. The reduction of a dialkyl ketimine could also be achieved, affording the expected amine with moderate optical purity (69% ee). Some amines which are precursors of very interesting biologically and pharmacologically active compounds have been prepared in excellent yields and enantiomeric excesses.
- Guijarro, David,Pablo, Oscar,Yus, Miguel
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supporting information; experimental part
p. 5265 - 5270
(2010/10/21)
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- Rapid, one-pot synthesis of α,α-disubstituted primary amines by the addition of Grignard reagents to nitriles under microwave heating conditions
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A series of α,α-disubstituted amines have been prepared in a simple and efficient one-pot procedure by the addition of Grignard reagents to a series of aliphatic, aromatic, and heteroaromatic nitriles. Key to this reported procedure is the unprecedented addition of the Grignard reagent to the nitrile under heating by microwave irradiation which both significantly improves reaction yields and reduces reaction times. In general, the Grignard addition reaction is complete within 5-10 min at 100 °C followed by rapid reduction with sodium borohydride to give the target amines.
- Gregg, Brian T.,Golden, Kathryn C.,Quinn, John F.,Wang, Hong-Jun,Zhang, Wei,Wang, Ruifang,Wekesa, Francis,Tymoshenko, Dmytro O.
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experimental part
p. 3978 - 3981
(2009/10/04)
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- α-Methylation at benzylic fragment of N-aryl-N′-benzyl ureas provides TRPV1 antagonists with better pharmacokinetic properties and higher efficacy in inflammatory pain model
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SAR studies for N-aryl-N′-benzyl urea class of TRPV1 antagonists have been extended to cover α-benzyl alkylation. Alkylated compounds showed weaker in vitro potencies in blocking capsaicin activation of TRPV1 receptor, but possessed improved pharmacokinetic properties. Further structural manipulations that included replacement of isoquinoline core with indazole and isolation of single enantiomer led to TRPV1 antagonists like (R)-16a with superior pharmacokinetic properties and greater potency in animal model of inflammatory pain.
- Gomtsyan, Arthur,Bayburt, Erol K.,Keddy, Ryan,Turner, Sean C.,Jinkerson, Tammie K.,Didomenico, Stanley,Perner, Richard J.,Koenig, John R.,Drizin, Irene,McDonald, Heath A.,Surowy, Carol S.,Honore, Prisca,Mikusa, Joe,Marsh, Kennan C.,Wetter, Jill M.,Faltynek, Connie R.,Lee, Chih-Hung
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p. 3894 - 3899
(2008/02/09)
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- Fused azabicyclic compounds that inhibit vanilloid receptor subtype 1 (VR1) receptor
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Compounds of formula (I) are novel VR1 antagonists that are useful in treating pain, inflammatory thermal hyperalgesia, urinary incontinence and bladder overactivity, wherein X1, X2, X3, X4, X5, R5, R6, R7, R8a, R8b, R9, Z1, Z2 and L are as defined in the description.
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-
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- Fused azabicyclic compounds that inhibit vanilloid receptor subtype 1 (VR1) receptor
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Compounds of formula (I) are novel VR1 antagonists that are useful in treating pain, inflammatory thermal hyperalgesia, urinary incontinence and bladder overactivity.
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Page/Page column 41
(2010/02/11)
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- Fused azabicyclic compounds that inhibit vanilloid receptor subtype 1 (VR1) receptor
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Compounds of formula (I) are novel VR1 antagonists that are useful in treating pain, inflammatory thermal hyperalgesia, urinary incontinence and bladder overactivity.
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- Chemoselective reductive alkylation of ammonia with carbonyl compounds: Synthesis of primary and symmetrical secondary amines
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An efficient, general procedure for highly chemoselective reductive mono-alkylation of ammonia with ketones is reported. Treatment of ketones with ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction, and a straightforward workup afforded primary amines in good to excellent yields. Reductive alkylation of ammonia with aldehydes, on the other hand, afforded the corresponding symmetrical secondary amines selectively.
- Miriyala, Bruhaspathy,Bhattacharyya, Sukanta,Williamson, John S.
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p. 1463 - 1471
(2007/10/03)
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- Highly regioselective hydrogenolysis of bis(α-methylbenzyl)amine derivatives affected by the trifluoromethyl substituent on the aromatic ring
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(Matrix presented) The highly regioselective hydrogenolysis of bis(α-methylbenzyl)amine derivatives proceeded with influence not from the electronic effect but from the steric effect of the trifluoromethyl substituent on the aromatic ring to provide a practical asymmetric synthesis of trifluoromethyl-substituted α-phenylethylamines.
- Kanai, Masatomi,Yasumoto, Manabu,Kuriyama, Yokusu,Inomiya, Kenjin,Katsuhara, Yutaka,Higashiyama, Kimio,Ishii, Akihiro
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p. 1007 - 1010
(2007/10/03)
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- Optically Active Amines. 31. Spectral Observations on the Substituted Benzene Chromophore
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Examination of the isotropic absorption and circular dichroism spectra of para-substituted and 3,5-disubstituted α-phenyl- and α-benzylethylamines and their hydrochlorides indicates that the sign of 1Lb Cotton effects (CEs) of the be
- Smith, Howard E.,Neergaard, Jon R.,Paulis, Tomas de,Chen, Fu-Ming
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p. 1578 - 1584
(2007/10/02)
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