- Quaternary ammoniums and a cationic sodium complex as supramolecular catalysts in ring-opening of epoxides by amines
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Supramolecular ionic organocatalysts and a metal-based catalyst were investigated in the ring-opening of epoxides by amines, without any artifice to enhance conversion (i.e., solvophobic effect, extended reaction time, heating, excess of amine, high catalyst loading). Different β-amino-alcohols were obtained in satisfying conversion (50-80%) in 24 h, under mild conditions.
- Thomas, Coralie,Brut, Sébastien,Bibal, Brigitte
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Read Online
- Syntheses, structures and catalytic activities of low-coordinated rare-earth metal complexes containing 2,2′-pyridylpyrrolides
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Reactions of the ligand precursors 2-(2′-pyridyl)-3,5-Me2-pyrrole (L1H) and 2-(2-pyridyl)-3,4,5-Me3-pyrrole (L2H) with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 in toluene afforded a series of low-coordinated rare-earth metal bis-amido complexes L1RE[N(SiMe3)2]2 [RE = Y (1a), Dy (1b), Er (1c), Yb (1d)] and L2RE[N(SiMe3)2]2 [RE = Y (2a), Dy (2b), Er (2c), Yb (2d)]. With the ionic radius of rare-earth metal increasing, the reaction of L1H and [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 gave dinuclear complexes (L1)2RE(μ-Cl)(μ-η5:η1:η1-L1)RE(L1)[N(SiMe3)2]2 [RE = Sm (1e), Pr (1f)]; however, the reaction of L2H and [(Me3Si)2N]3Sm(μ-Cl)Li(THF)3 afforded (L2)2Sm[N(SiMe3)2]2 (2e). Results indicated that the ionic radius of rare-earth metal and subtle change in the ligands have substantial effects on the structure and bonding mode of complexes. The complexes showed a high catalytic activity for the ring-opening reaction of cyclohexene oxide with amines to afford various β-aminoalcohols under mild solvent-free conditions.
- Du, Jun,Zhou, Shuangliu,Zhang, Xiuli,Zhang, Lijun,Cui, Peng,Huang, Zeming,Wei, Yun,Zhu, Xiancui,Wang, Shaowu
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- M-Type SrFe12O19Ferrite: An Efficient Catalyst for the Synthesis of Amino Alcohols under Solvent-Free Conditions
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Magnetically separable strontium hexaferrite SrFe12O19 was prepared using the chemical coprecipitation method, and the nanostructured material was characterized by X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and BET analysis. The SEM images showed the homogeneity of the chemical composition of SrFe12O19 and uniform distribution of size and morphology. The pore size of the nanomaterial and its specific area were determined by BET measurements. Strontium hexaferrite SrFe12O19 exhibited a strong magnetic field, which is highly suitable in the heterogeneous catalysis as it can be efficiently separated from the reaction. The magnetic nanocatalyst showed high activity and environmentally benign heterogeneous catalysts for the epoxide ring-opening with amines affording β-amino alcohols under solvent-free conditions. When unsymmetrical epoxides were treated in the presence of aromatics amines, the regioselectivity was influenced by the electronic and steric factors. Total regioselectivity was observed for the reactions performed with aliphatic amines. The magnetically SrFe12O19 nanocatalyst showed excellent recyclability with continuously good catalytic activities after four cycles.
- Laayati, Mouhsine,Hasnaoui, Ali,Abdallah, Nayad,Oubaassine, Saadia,Fkhar, Lahcen,Mounkachi, Omar,El Houssame, Soufiane,Ait Ali, Mustapha,El Firdoussi, Larbi
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- Asymmetric amination of meso-epoxide with vegetable powder as a low-toxicity catalyst
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This paper describes the scope and limitation of substrates subjected to asymmetric amination with epoxides catalyzed by a soluble soybean polysaccharide (Soyafibe S-DN), which we recently discovered from the reaction of 1,2-epoxycyclohexane with cyclopropylamine. Various meso-epoxides reacted with various amines afforded the corresponding products with good enantiomeric selectivity. Since it was found that pectin was found to have a catalytic ability after screening commercially available polysaccharides, we studied 33 different vegetable powders having pectic substances, and we found that many vegetable powders showed catalytic ability. These results should guide in using vegetable components as low-toxic catalysts for the production of pharmaceuticals.
- Asano, Tatsuhiro,Kurata, Hiroyuki,Takeuchi, Yuki,Tsuzaki, Kazuya,Wada, Koichi
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- Three-dimensional {Co3+-Zn2+} and {Co 3+-Cd2+} networks originated from carboxylate-rich building blocks: Syntheses, structures, and heterogeneous catalysis
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The present work shows the utilization of Co3+ complexes appended with either para- or meta-arylcarboxylic acid groups as the molecular building blocks for the construction of three-dimensional {Co 3+-Zn2+} and {Co3+-Cd2+} heterobimetallic networks. The structural characterizations of these networks show several interesting features including well-defined pores and channels. These networks function as heterogeneous and reusable catalysts for the regio- and stereoselective ring-opening reactions of various epoxides and size-selective cyanation reactions of assorted aldehydes.
- Kumar, Girijesh,Gupta, Rajeev
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p. 10773 - 10787
(2013/10/22)
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- Efficient solvent-free aminolysis of epoxides under (C4H 12N2)2[BiCl6]Cl·H 2O catalysis
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An efficient and rapid procedure for ring opening of various epoxides with aromatic, aliphatic and heterocyclic amines is developed at room temperature under solvent-free conditions in the presence of (C4H 12N2)2[BiCl6]Cl·H 2O (1 mol %). This catalyst can be reused several times without losing of its activity.
- Lu, Hong-Fei,Sun, Lei-Lei,Le, Wen-Jun,Yang, Fei-Fei,Zhou, Jun-Tao,Gao, Yu-Hua
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experimental part
p. 4267 - 4272
(2012/09/22)
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- Zinc tetrafluoroborate hydrate as a mild catalyst for epoxide ring opening with amines: Scope and limitations of metal tetrafluoroborates and applications in the synthesis of antihypertensive drugs (RS)/(R)/(S)-metoprolols
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The scope and limitations of metal tetrafluoroborates have been studied for epoxide ring-opening reaction with amines, and Zn(BF4) 2?xH2O has been found to be a mild and efficient catalyst affording high yields under solvent-free conditions at rt with excellent chemo-, regio-, and stereoselectivities. The catalytic efficiency followed the order Zn(BF4)2?xH2O ? Cu(BF4)2?xH2O > Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > LiBF4 for reactions with cyclohexene oxide and Zn(BF4)2?xH2O ? Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > Cu(BF4)2?xH2O for stilbene oxide, but AgBF4 was ineffective. For reaction of styrene oxide with aniline, the metal tetrafluoroborates exhibited comparable regioselectivity (1:99-7:93) with preferential reaction at the benzylic carbon of the epoxide ring. A reversal of regioselectivity (91:1-69:31) in favor of the reaction at the terminal carbon of the epoxide ring was observed for reaction with morpholine. The regioselectivity was dependent on the electronic and steric factors of the epoxide and the pKa of the amine and independent of amine nucleophilicity. The role of the metal tetrafluoroborates is envisaged as "electrophile nucleophile dual activation" through cooperativity of coordination, charge-charge interaction, and hydrogen-bond formation that rationalizes the catalytic efficiency, substrate reactivity, and regioselectivity. The methodology was used for synthesis of cardiovascular drug metoprolol as racemic and enriched enantiomeric forms.
- Pujala, Brahmam,Rana, Shivani,Chakraborti, Asit K.
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experimental part
p. 8768 - 8780
(2011/12/04)
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- Optimisation of the Anti-Trypanosoma brucei Activity of the Opioid Agonist U50488
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Screening of the Sigma-Aldrich Library of Pharmacologically Active Compounds (LOPAC) against cultured Trypanosoma brucei, the causative agent of African sleeping sickness, resulted in the identification of a number of compounds with selective antiproliferative activity over mammalian cells. These included (+)-(1R,2R)-U50488, a weak opioid agonist with an EC50 value of 59nM as determined in our T.brucei invitro assay reported previously. This paper describes the modification of key structural elements of U50488 to investigate structure-activity relationships (SAR) and to optimise the antiproliferative activity and pharmacokinetic properties of this compound.
- Smith, Victoria C.,Cleghorn, Laura A. T.,Woodland, Andrew,Spinks, Daniel,Hallyburton, Irene,Collie, Iain T.,YiMok,Norval, Suzanne,Brenk, Ruth,Fairlamb, Alan H.,Frearson, Julie A.,Read, Kevin D.,Gilbert, Ian H.,Wyatt, Paul G.
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experimental part
p. 1832 - 1840
(2012/06/18)
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- Aminolysis of epoxides using iridium trichloride as an efficient catalyst
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Iridium trichloride catalyzes the ring opening of epoxides by aryl, heterocyclic, or aliphatic amines under mild conditions. The reactions proceed at room temperature to afford the corresponding b-amino alcohols in excellent yields. In general, the aminolysis of cyclopentene oxide is faster than that of cyclohexene oxide in the presence of iridium trichloride as a catalyst. Georg Thieme Verlag Stuttgart.
- Agarwal, Jyoti,Duley, Anju,Rani, Rashmi,Peddinti, Rama Krishna
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experimental part
p. 2790 - 2796
(2010/01/21)
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- Microwave-enhanced bismuth triflate-catalyzed epoxide opening with aliphatic amines
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In the presence of a catalytic amount of Bi(OTf)3·4H2O and under microwave irradiation, neat mixtures of epoxides and amines afforded smoothly the corresponding 2-amino alcohols. A wide variety of aliphatic amines were reacted with cycloalkene oxide, styrene oxide, and stilbene oxide. The reaction proceeded rapidly and afforded the 2-amino alcohols in high up to quantitative yields. All products could be obtained without aqueous work-up by simple filtration.
- Ollevier, Thierry,Nadeau, Etienne
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p. 1546 - 1550
(2008/09/19)
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- Improved procedure for the synthesis of enamine N-oxides
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(Chemical Equation Presented) An improved procedure for the preparation of enamine N-oxides involving aminolysis of epoxides, chlorination, N-oxidation, and dehydrochlorination is described. Although isolated β-chloroamine N-oxides are prone to rearrangem
- Bernier, David,Blake, Alexander J.,Woodward, Simon
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p. 4229 - 4232
(2008/09/20)
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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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- Zinc(II) perchlorate hexahydrate catalyzed opening of epoxide ring by amines: Applications to synthesis of (RS)/(R)-propranolols and (RS)/(R)/(S)-naftopidils
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(Figure Presented) Commercially available zinc(II) Perchlorate hexahydrate [Zn(ClO4)2·6H2O] was found to be a new and highly efficient catalyst for opening of epoxide rings by amines affording 2-amino alcohols in high yields under solvent-free conditions and with excellent chemo-, regio-, and stereoselectivities. For unsymmetrical epoxides, the regioselectivity was influenced by the electronic and steric factors associated with the epoxides and the amines. A complementarity in the regioselectivity was observed during the reaction of styrene oxide with aromatic and aliphatic amines: aromatic amines provided amino alcohols from nucleophilic attack at the benzylic carbon as major products whereas aliphatic amines resulted in formation of the amino alcohols through reaction at the terminal carbon atom of the epoxide ring as the major/sole products. Reaction of aniline with various glycidic ethers gave the amino alcohols by regioselective nucleophilic attack at the terminal carbon atom of the epoxide ring as the only/major product. Zinc(II) Perchlorate hexahydrate was found to be the best catalyst compared to other metal Perchlorates. The counteranion modulated the catalytic property of the various Zn(II) compounds that followed the order Zn(ClO4) 2·6H2O Zn(BF4)2 ~ Zn(OTf)2 ZnI2 > ZnBr2 > ZnCl2 > Zn(OAc)2 > Zn(CO3)2 in parallelism with the acidic strength of the corresponding protic acids (except for TfOH). The applicability of the methodology was demonstrated by the synthesis of cardiovascular drugs propranolol and naftopidil as racemates and optically active enantiomers.
- Shivani,Pujala, Brahmam,Chakraborti, Asit K.
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p. 3713 - 3722
(2008/02/05)
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- Synthesis and biological studies of novel 2-aminoalkylethers as potential antiarrhythmic agents for the conversion of atrial fibrillation
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A series of 2-aminoalkylethers prepared as potential antiarrhythmic agents is described. The present compounds are mixed sodium and potassium ion channel blockers and exhibit antiarrhythmic activity in a rat model of ischemia-induced arrhythmias. Structure-activity studies led to the identification of three compounds 5, 18, and 26, which were selected based on their particular in vivo electrophysiological properties, for studies in two canine atrial fibrillation (AF) models. The three compounds converted AF in both models, but only compound 26 was shown to be orally bioavailable. Resolution of the racemate 26 into its corresponding enantiomers 40 and 41 and subsequent biological testing of these enantiomers led to the selection of (1S,2S)-1-(1-naphthalenethoxy)-2-(3- ketopyrrolidinyl)cyclohexane monohydrochloride (41) as a potential atrial selective antiarrhythmic candidate for further development.
- Plouvier, Bertrand,Beatch, Gregory N.,Jung, Grace L.,Zolotoy, Alexander,Sheng, Tao,Clohs, Lilian,Barrett, Terrance D.,Fedida, David,Wang, Wei Q.,Zhu, Jeff J.,Liu, Yuzhong,Abraham, Shlomo,Lynn, Leah,Dong, Ying,Wall, Richard A.,Walker, Michael J. A.
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p. 2818 - 2841
(2008/02/09)
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- Solid lithium perchlorate as a powerful catalyst for the synthesis of β-aminoalcohols under solvent-free conditions
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Lithium perchlorate catalyzed the ring opening of epoxides with amines to provide the corresponding β-aminoalcohols in excellent yields with high regioselectivity. The reaction proceeds rapidly under mild and neutral conditions and worked well with primary, secondary, aliphatic, aromatic, and hindered amines in short times at room temperature, in the absence of solvent.
- Azizi, Najmodin,Saidi, Mohammad R.
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p. 505 - 507
(2007/10/03)
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- Highly chemoselective addition of amines to epoxides in water
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(Chemical Equation Presented) Aminolysis of a variety of epoxides by aliphatic and aromatic amines in water, in the absence of any catalyst with high yields, is reported. β-Amino alcohols were formed under mild conditions with high selectivity and in excellent yields.
- Azizi, Najmodin,Saidi, Mohammad R.
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p. 3649 - 3651
(2007/10/03)
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- Scandium triflate as an efficient and useful catalyst for the synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines under solvent-free conditions
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A simple and efficient method has been developed for the synthesis of β-amino alcohols by ring opening of epoxides in the presence of a catalytic amount of Sc(OTf)3 at room temperature under solvent-free conditions. The reaction works well with both aromatic and aliphatic amines. High regio-, and diastereoselectivity can be considered as a noteworthy advantage of this method.
- Placzek, Andrew T.,Donelson, James L.,Trivedi, Rushi,Gibbs, Richard A.,De, Surya K.
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p. 9029 - 9034
(2007/10/03)
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- Lithium bromide, an inexpensive and efficient catalyst for opening of epoxide rings by amines at room temperature under solvent-free condition
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Lithium bromide has been found to be an inexpensive and efficient catalyst for the opening of epoxide rings by amines, and this provides an environmentally friendly method for the synthesis of β-amino alcohols. Aromatic and aliphatic amines react with cycloalkene oxides to exclusively form trans-2-(aryl/alkylamino)cycloalkanols in high yields. A 98-100% selectivity in favour of nucleophilic attack at the benzylic carbon atom of styrene oxide is observed with aromatic amines. However, aliphatic amines exhibit a marginal preference for the reaction at the terminal carbon atom of the epoxide ring in styrene oxide. Non-styrenoidal, unsymmetrical alkene oxides undergo selective nucleophilic attack at the sterically less hindered carbon atom by aniline. The chelation effect of the Li+ ion enables selective opening of the epoxide ring in 3-phenoxypropylene oxide in the presence of styrene oxide. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Chakraborti, Asit K.,Rudrawar, Santosh,Kondaskara, Atul
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p. 3597 - 3600
(2007/10/03)
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- Scope and limitations of montmorillonite K 10 catalysed opening of epoxide rings by amines
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Montmorillonite K 10 efficiently catalyses the opening of epoxide rings by amines in high yields with excellent regio- and diastereo-selectivities under solvent-free conditions at room temperature affording an improved process for synthesis of 2-amino alcohols. Reaction of cyclohexene oxide with aryl/alkyl amines leads to the formation of trans-2-aryl/alkylaminocyclohexanols. For unsymmetrical epoxides, the regioselectivity is controlled by the electronic and steric factors associated with the epoxide and the amine. Selective nucleophilic attack at the benzylic carbon of styrene oxide takes place with aromatic amines, whereas, aliphatic amines exhibit preferential nucleophilic attack at the terminal carbon. Aniline reacts selectively at the less hindered carbon of other unsymmetrical epoxides. The difference in the internal strain energy of the epoxide ring in cycloalkene oxides and alkene oxides led to selective nucleophilic opening of cyclohexene oxide by aniline in the presence of styrene oxide. Due to the chelation effect, selective activation of the epoxide ring in 3-phenoxy propylene oxide takes place in the presence of styrene oxide leading to preferential cleavage of the epoxide ring in 3-phenoxy propylene oxide by aniline.
- Chakraborti, Asit K.,Kondaskar, Atul,Rudrawar, Santosh
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p. 9085 - 9091
(2007/10/03)
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- An efficient synthesis of 2-amino alcohols by silica gel catalysed opening of epoxide rings by amines
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Silica gel (60-120 mesh) efficiently catalyses the opening of epoxide rings by amines at rt under solvent-free conditions providing an easy method for the synthesis of 2-amino alcohols. Aromatic and aliphatic amines react with cyclohexene oxide with exclu
- Chakraborti, Asit K.,Rudrawar, Santosh,Kondaskar, Atul
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p. 1277 - 1280
(2007/10/03)
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- AMINOCYCLOHEXYL ETHER COMPOUNDS AND USES THEREOF
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Aminocyclohexyl ether compounds of formula (I), or a solvate or pharmaceutically acceptable salt thereof: are disclosed. In said formula, A, X and R, -R5 have the meanings given in the description. The compounds of the present invention may be inco
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- Chemoenzymatic preparation of optically active trans-cyclohexane-1,2- diamine derivatives: An efficient synthesis of the analgesic U-(-)-50,488
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Stereoespecific syntheses of (±)-trans-N,N-cyclohexane-1,2-diamines ((±)-4a-g) were carried out from the corresponding (±)-trans-N,N- dialkylaminocyclohexanols by successive treatment with mesyl chloride and aqueous ammonia. The stereochemical outcome indicates the formation of a meso-aziridinium ion intermediate, Kinetic resolutions of diamines (±)-4 were efficiently accomplished in aminolysis reactions catalyzed by lipase B from Candida antarctica with ethyl acetate as the solvent and acyl donor. Acetamides and the remaining diamines, isolated as the benzyloxycarbonyl derivatives, were obtained with very high ee values (92-99%), One of the carbamates was used as a precursor of the analgesic U-(-)-50,488.
- Gonzalez-Sabin, Javier,Gotor, Vicente,Rebolledo, Francisca
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p. 5788 - 5794
(2007/10/03)
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- ZrCl4 as a new and efficient catalyst for the opening of epoxide rings by amines
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Zirconium(IV) chloride catalyses the nucleophilic opening of epoxide rings by amines leading to the efficient synthesis of β-amino alcohols. The reaction works well with aromatic and aliphatic amines in short times at room temperature in the absence of solvent. Exclusive trans stereoselectivity is observed for cyclic epoxides. Aromatic amines exhibit excellent regioselectivity for preferential nucleophilic attack at the sterically less hindered position during the reaction with unsymmetrical epoxides. However, in case of styrene oxide, selective formation of the benzylic amine was observed during the reactions with aromatic amines.
- Chakraborti, Asit K.,Kondaskar, Atul
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p. 8315 - 8319
(2007/10/03)
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- Towards phase-transfer catalysts with a chiral anion: Inducing asymmetry in the reactions of cations
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The ability of chiral anions, for example bis[1,1′-bi-2-naphtholato]borate, to induce asymmetry in the reactions of prochiral cations was investigated. Ion-pairing of a borate anion with an aziridinium ion was demonstrated by NMR spectroscopy. The additio
- Carter, Christabel,Fletcher, Sarah,Nelson, Adam
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p. 1995 - 2004
(2007/10/03)
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- Diamino benzo[b]thiophene derivatives as a novel class of active site directed thrombin inhibitors: 3. Enhancing activity by imposing conformational restriction in the C-4'' side chain
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The preparation and biological evaluation of a series of benzo[b]thiophene diamine thrombin inhibitors possessing conformationally restricted C-4'' linkers are reported. Compared to the parent compounds 1a/b, the unsaturated derivatives 3a/b exhibited a m
- Bastian, Jolie A.,Chirgadze, Nickolay,Denney, Michael L.,Gifford-Moore, Donetta S.,Sall, Daniel J.,Smith, Gerald F.,Wikel, James H.
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p. 363 - 368
(2007/10/03)
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- Dibasic benzo[b]thiophene derivatives as a novel class of active site directed thrombin inhibitors: 4. SAR studies on the conformationally restricted C3-side chain of hydroxybenzo[b]thiophenes
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A novel series of benzo[b]thiophene diamine thrombin inhibitors with a conformationally restricted C3-side chain 3 was investigated. The constrained C3-side chain by a cyclohexyl ring contributed to not only an additive but also a synergistic effect on the thrombin inhibitory activity. The SAR studies resulted in the discovery of a potent thrombin inhibitor 27 that was over 750-fold more potent than the initial lead compound 1.
- Takeuchi, Kumiko,Kohn, Todd J.,Sall, Daniel J.,Denney, Michael L.,McCowan, Jefferson R.,Smith, Gerry F.,Gifford-Moore, Donetta S.
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p. 759 - 764
(2007/10/03)
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- Ytterbium Triflate and High Pressure-mediated Ring Opening of Epoxides with Amines
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Ring opening of epoxides with amines in THF takes place very readily in the presence of catalytic amounts of ytterbium triflate to give the corresponding β-amino alcohols in good to high yields.With tri- and tetra-substituted epoxides, the use of an excess (2 - 3 equiv.) of the amine is needed.The Yb(OTf)3-catalysed reaction of epoxides with amines in CH2Cl2 is quite complex; the yield of amino alcohols is generally lower and depends upon the addition order of the catalyst, amine and epoxide.The ring opening is accomplished also under high pressures in the absence of Yb(OTf)3.Ring opening with a combination of Yb(OTf)3 in CH2Cl2 and high pressure is more effective than the use, independently, of either Yb(OTf)3 or the high-pressure method.Oxetanes and β-lactones undergo ring opening in the presence of Yb(OTf)3.
- Meguro, Masaki,Asao, Naoki,Yamamoto, Yoshinori
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p. 2597 - 2602
(2007/10/02)
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- Regio- and Stereo-selective Ring Opening of Epoxides with Amide Cuprate Reagents
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Amide cuprate reagents attack the less hindered carbon atom of epoxides to give 1,2-amino alcohols in good yields; this procedure is applied to the synthesis of an aziridine alcohol bearing a carborane framework which is a potentially useful 10B carrier for boron neutron capture therapy.
- Yamamoto, Yoshinori,Asao, Naoki,Meguro, Masaki,Tsukada, Naofumi,Nemoto, Hisao,et al.
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p. 1201 - 1203
(2007/10/02)
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- Synthesis and Receptor Binding of Enantiomeric N-Substituted cis-N--2-(1-pyrrolidinyl)cyclohexylamines as High-Affinity ? Receptor Ligands
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N-Alkyl-substituted derivatives of (+)- and (-)-cis-N--2-(1-pyrrolidinyl)cyclohexylamine have been synthesized in nine steps in a stereospecific manner starting from cyclohexene oxide.The key step in the reaction sequence invo
- Radesca, Lilian,Bowen, Wayne D.,Paolo, Lisa Di,Costa, Brian R. de
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p. 3058 - 3065
(2007/10/02)
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- N-Methyl-N--1-phenylcyclopropanecarboxylic amides - analogs of U50488 with much reduced opiate affinity and loss of κ-selectivity
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(+/-)-N-methyl-N--1-phenylcyclopropanecarboxylic amide (1) and its dichloro analog (2) were synthesized.Compounds 1 and 2 are related to the κ-selective opiate U-50488 in that the benzylic methylene moiety in U-50488 has been replaced by a cyclopropane ring.As compared to U-50488, a 600-fold reduction in kappa-affinity was observed with these 2 compounds; while the reduction in μ-affinity was less than 2-fold.Unlike U-50488, 1 and 2 also show measurable δ-binding.To explain the observed anomaly, the steric interaction between the N-methyl group and the cyclopropane ring and the tendency of the cyclopropane ring to conjugate with the neighboring phenyl group, both affecting the accessible conformations of the amide side chains of 1 and 2, are cosidered important factors.
- Cheng, CY,Lu, HY,Lee, FM
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p. 125 - 128
(2007/10/02)
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- Synthesis of (1',2'-trans)-3-phenyl-1-[2'-(N-pyrrolidinyl)cyclohexyl]pyrrolid-2- ones as κ-selective opiates
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(1',2'-trans)-3-Phenyl-1-[2'-(N-pyrrolidinyl)cyclohexyl]pyrrolid-2- ones (1 and 2) and their 3,4-dichlorophenyl analogues (4 and 5) were synthesized as lactam analogues of U-50,488 (I; a κ-opiate analgesic developed by Upjohn Company). Compounds 1 and 2 w
- Cheng,Lu,Lee,Tam
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p. 758 - 762
(2007/10/02)
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- TETRAPHENYLSTIBONIUM TRIFLATE AS A REGIO- AND CHEMOSELECTIVE CATALYST IN THE REACTION OF OXIRANES WITH AMINES
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Tetraphenylstibonium triflate catalytically promotes the nucleophilic addition of amines to oxiranes under mild conditions, giving the corresponding β-amino alcohols regio- and chemoselectively.
- Fujiwara, Masahiro,Imada, Makoto,Baba, Akio,Matsuda, Haruo
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p. 739 - 742
(2007/10/02)
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- FACILE AMINOLYSIS OF EPOXIDES WITH DIETHYLALUMINUM AMIDES
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Treatment of an epoxide with a diethylaluminum amide in dichloromethane at room temperature affords the corresponding β-amino alcohol in good yield.
- Overman, Larry E.,Flippin, Lee A.
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p. 195 - 198
(2007/10/02)
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