- Understanding the Alkylation Mechanism of 3-Chloropiperidines – NMR Kinetic Studies and Isolation of Bicyclic Aziridinium Ions
-
The present study describes the kinetic analysis of the 3-chloropiperidine alkylation mechanism. These nitrogen mustard-based compounds are expected to react via a highly electrophilic bicyclic aziridinium ion, which is readily attacked by nucleophiles. Halide abstraction using silver salts with weakly coordinating anions lead to the isolation of these proposed intermediates, whereas their structure was confirmed by single crystal XRD. Kinetic studies of the aziridinium ions also revealed notable reactivity differences of the C5 gem-methylated compounds and their unmethylated counterparts. The observed reactivity trends were also reflected by NMR studies in aqueous solution and DNA alkylation experiments of the related 3-chloropiperidines. Therefore, the underlying Thorpe-Ingold effect might be considered as another option to adjust the alkylation activity of these compounds.
- Helbing, Tim,Georg, Mats,St?hr, Fabian,Carraro, Caterina,Becker, Jonathan,Gatto, Barbara,G?ttlich, Richard
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p. 5905 - 5913
(2021/10/29)
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- l -Proline as a Valuable Scaffold for the Synthesis of Novel Enantiopure Neonicotinoids Analogs
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In this research, six neonicotinoid analogs derived from l-proline were synthesized, characterized, and evaluated as insecticides against Xyleborus affinis. Most of the target compounds showed good to excellent insecticidal activity. To the best of our knowledge, this is the first report dealing with the use of enantiopure l-proline to get neonicotinoids. These results highlighted the compound 9 as an excellent candidate used as the lead chiral insecticide for future development. Additionally, molecular docking with the receptor and compound 9 was carried out to gain insight into its high activity when compared to dinotefuran. Finally, the neurotoxic evaluation of compound 9 showed lower toxicity than the classic neonicotinoid dinotefuran.
- Bonilla-Landa, Israel,Cuapio-Mu?oz, Ulises,Luna-Hernández, Axel,Reyes-Luna, Alfonso,Rodríguez-Hernández, Alfredo,Ibarra-Juarez, Arturo,Suarez-Mendez, Gabriel,Barrera-Méndez, Felipe,Caram-Salas, Nadia,Enríquez-Medrano, J. Francisco,Díaz De León, Ramón E.,Olivares-Romero, José Luis
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p. 1455 - 1465
(2021/02/16)
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- Synthesis of Optically Active N -(4-Hydroxynon-2-enyl)pyrrolidines: Key Building Blocks in the Total Synthesis of Streptomyces coelicolor Butanolide 5 (SCB-5) and Virginiae Butanolide A (VB-A)
-
Starting from 5-methylhexanal and (S)-configured N -propargylprolinol ethers, coupling delivered N -(4-hydroxynon-2-ynyl)prolinol derivatives as mixtures of C4 diastereomers. Resolution of the epimers succeeded after introduction of an (R)-mandelic ester derivative and subsequent HPLC separation. Alternatively, suitable oxidation gave the corresponding alkynyl ketone. Midland reagent controlled diastereoselective reduction afforded a defined configured propargyl alcohol with high selectivity. LiAlH 4reduction and Mosher analyses of the allyl alcohols enabled structure elucidation. The suitably protected products are used as key intermediates in enantioselective Streptomyces γ-butyrolactone signaling molecule total syntheses.
- Donges, Jonas,Hofmann, Sandra,Walter, Johannes C.,Reichertz, Julia,Brüggemann, Moritz,Frank, Andrea,Nubbemeyer, Udo
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p. 2632 - 2642
(2021/04/27)
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- Controlled Reduction of Carboxamides to Alcohols or Amines by Zinc Hydrides
-
New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH-ZnI2 system delivers alcohols and NaH-ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc hydride (ZnH2)∞ is responsible for alcohol formation, whereas dimeric zinc chloride hydride (H?Zn?Cl)2 is the key species for the production of amines.
- Ong, Derek Yiren,Yen, Zhihao,Yoshii, Asami,Revillo Imbernon, Julia,Takita, Ryo,Chiba, Shunsuke
-
supporting information
p. 4992 - 4997
(2019/03/13)
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- Reduction of N,N-Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite
-
A new and concise protocol for selective reduction of N,N-dimethylamides into aldehydes was established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH-NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N-dimethylamides with wide substituent compatibility. Retention of α-chirality in the reduction of α-enantioriched amides was accomplished. Use of sodium deuteride (NaD) offers a new step-economical alternative to prepare deuterated aldehydes with high deuterium incorporation rate. The NaH-NaI composite exhibits unique chemoselectivity for reduction of N,N-dimethylamides over ketones.
- Chan, Guo Hao,Ong, Derek Yiren,Yen, Zhihao,Chiba, Shunsuke
-
-
- Synthesis of diastereomeric pyrrolidine sulfamides via anchimerically assisted nucleophilic substitution reactions
-
The Mitsunobu reaction was employed in a key step during the development of a convenient synthetic route for the enantioselective preparation of pyrrolidine-sulfamide ligands from (R)- or (S)- [(S)-1-benzylpyrrolidin-2-yl](phenyl)methanol, and employing tert-butyl pyrrolidin-1-yl-sulfonylcarbamate as a non-conventional nucleophilic source. Although it is well documented that the exposure of this type of diastereomeric amino alcohols to the above-mentioned nucleophile usually leads to the formation of piperidines via ring expansion, either through classical nucleophilic substitution or the Mitsunobu version, only the pyrrolidine derivatives were generated with retention of configuration on the exocyclic stereocenter, owing to the neighboring group participation (internal backside nucleophilic substitution, SNib). Final removal of the N-Boc protecting group from the sulfamide fragment afforded chiral compounds with significant potential as chiral ligands in asymmetric catalysis.
- Vargas-Caporali, Jorge,van der Lee, Arie,Dewynter, Georges,Juaristi, Eusebio
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p. 352 - 358
(2018/05/22)
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- Targeting Alzheimer's disease by investigating previously unexplored chemical space surrounding the cholinesterase inhibitor donepezil
-
A series of twenty seven acetylcholinesterase inhibitors, as potential agents for the treatment of Alzheimer's disease, were designed and synthesised based upon previously unexplored chemical space surrounding the molecular skeleton of the drug donepezil, which is currently used for the management of mild to severe Alzheimer's disease. Two series of analogues were prepared, the first looking at the replacement of the piperidine ring in donepezil with different sized saturated N-containing ring systems and the second looking at the introduction of different linkers between the indanone and piperidine rings in donepezil. The most active analogue 5,6-dimethoxy-1-oxo-2,3-dihydro-1H-inden-2-yl 1-benzylpiperidine-4-carboxylate (67) afforded an in vitro IC50value of 0.03 ± 0.07 μM against acetylcholinesterase with no cytotoxicity observed (IC50of >100 μM, SH-SY5Y cell line). In comparison donepezil had an IC50of 0.05 ± 0.06 μM and an observed cytotoxicity IC50of 15.54 ± 1.12 μM. Molecular modelling showed a strong correlation between activity and in silico binding in the active site of acetylcholinesterase.
- van Greunen, Divan G.,Cordier, Werner,Nell, Margo,van der Westhuyzen, Chris,Steenkamp, Vanessa,Panayides, Jenny-Lee,Riley, Darren L.
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p. 671 - 690
(2017/02/10)
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- Transition Metal-Free Selective Double sp3 C-H Oxidation of Cyclic Amines to 3-Alkoxyamine Lactams
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The first chemical method for selective dual sp3 C-H functionalization at the alpha-and beta positions of cyclic amines to their corresponding 3-alkoxyamine lactams is reported. Unlike traditional Cα-H oxidation of amines to amides mediated by transition metals, the present protocol, which involves the use of NaClO2/TEMPO/NaClO in either aqueous or organic solvent, not only allows the Cα-H oxidation but also the subsequent functionalization of the unreactive β-methylene group in an unprecedented tandem fashion and using environmentally friendly reactants.
- Osorio-Nieto, Urbano,Chamorro-Arenas, Delfino,Quintero, Leticia,H?pfl, Herbert,Sartillo-Piscil, Fernando
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p. 8625 - 8632
(2016/09/28)
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- Resin-immobilized pyrrolidine-based chiral organocatalysts for asymmetric Michael additions of ketones and aldehydes to nitroolefins
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Based on the electrostatic adsorption between acidic resins and organocatalysts, a series of resin-supported chiral organocatalysts were designed and synthesized. They were evaluated for the asymmetric Michael addition of cyclohexanone with nitrostyrene, in which, catalyst 3 (Fig. 1) exhibited the best catalytic performance. This reaction proceeded under catalyst 3 smoothly at room temperature without any solvent or additive and could give product with high yield (95%) and good stereoselectivity (90% ee, 98:2 dr). Encouragingly, catalyst 3 was easily isolated and reused for 16 consecutive runs without obvious loss of reaction enantioselectivity. Furthermore, it was successfully applied to catalyze the reactions of a series of ketones and aldehydes with nitroolefins.
- Zhang, Richeng,Yin, Guohui,Li, Yang,Yan, Xilong,Chen, Ligong
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p. 3461 - 3464
(2015/02/18)
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- Highly chemoselective aerobic oxidation of amino alcohols into amino carbonyl compounds
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The direct oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds in which 2-azaadamantane N-oxyl (AZADO)/copper catalysis is used. The catalytic system developed leads to the alcohol-selective oxidation of various unprotected amino alcohols, carrying a primary, secondary, or tertiary amino group, in good to high yield at ambient temperature with exposure to air, thus offering flexibility in the synthesis of nitrogen-containing compounds. Strong as an ox: The highly chemoselective aerobic oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has been achieved by using 2-azaadamantane N-oxyl (AZADO)/copper catalysis. This catalytic system oxidizes not only alcohols with tertiary amino groups but also those with secondary and primary amines in good to high yield at ambient temperature in air. bpy=2,2-bipyridyl, DMAP=4-(N,N-dimethylamino)pyridine.
- Sasano, Yusuke,Nagasawa, Shota,Yamazaki, Mai,Shibuya, Masatoshi,Park, Jaiwook,Iwabuchi, Yoshiharu
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p. 3236 - 3240
(2014/04/03)
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- Flexible synthesis of planar chiral azoninones and optically active indolizidinones
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The flexible synthesis of defined substituted optically active indolizidinones starting from chiral pool (S)-proline and trans 4-hydroxy-(S)-proline is described. Several defined 2-vinylpyrrolidines were generated in short sequences. The aza-Claisen rearr
- Bohland, Frank,Erlin, Irina,Platte, Lukas,Schr?der, Maike,Schollmeyer, Dieter,Nubbemeyer, Udo
-
supporting information
p. 6272 - 6284
(2015/03/30)
-
- Asymmetric synthesis of (-)-(1R,7aS)-absouline
-
The most efficient and concise asymmetric synthesis of (-)-(1R,7aS)- absouline to date, which was accomplished in eight steps and 20% overall yield from commercially available starting materials, is described. The doubly diastereoselective conjugate addit
- Davies, Stephen G.,Fletcher, Ai M.,Lebée, Clément,Roberts, Paul M.,Thomson, James E.,Yin, Jingda
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p. 1369 - 1377
(2013/02/23)
-
- Highly practical iron-catalyzed C-O cleavage reactions
-
Facile iron-catalyzed cleavage of various allyl, cinnamyl and benzyl C-O linkages has been effected in the presence of ethylmagnesium chloride. The protocol is operationally simple (xylene-THF, r.t., 1 h), requires low catalyst loading (1 mol% FeCl2) and tolerates halides, esters, amines, ethers and olefins. The allyl moiety is converted to volatile hydrocarbons which renders laborious product separation unnecessary.
- Gaertner, Dominik,Konnerth, Hannelore,Von Wangelin, Axel Jacobi
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p. 2541 - 2545
(2013/09/24)
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- Optically active imidazole N-oxides derived from l-prolinamine1
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Starting with (S)-1-benzylprolinamine and α-hydroxyimino ketones, enantiomerically pure bisheterocyclic imidazole N-oxides bearing the (S)-configured N-benzyl(pyrrolidin-2-yl)methyl residue were prepared. These N-oxides reacted with 2,2,4,4-tetramethylcyclobutane-1,3-dithione to give the corresponding optically active imidazole-2-thione derivatives via a sulfur transfer reaction. Reduction of the N-oxides with Raney-nickel led to deoxygenation, whereas catalytic hydrogenation (Pd/C) in ethanol occurred with simultaneous deoxygenation and debenzylation, leading to optically active 1-(pyrrolidin-2-yl)methyl-1H-imidazoles. Alkylation of the prepared imidazole N-oxides and their respective imidazoles with butyl and hexyl bromide and subsequent anion exchange gave optically active N-alkoxy- and N-alkylimidazolium tetrafluoroborates, respectively, with the properties of 'room temperature ionic liquids'.
- Mloston, Grzegorz,Wroblewska, Aneta,Obijalska, Emilia,Heimgartner, Heinz
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p. 958 - 965
(2013/09/23)
-
- Synthesis of acyclic ketones by catalytic, bidirectional homologation of formaldehyde with nonstabilized diazoalkanes. Application of a chiral diazomethyl(pyrrolidine) in total syntheses of erythroxylon alkaloids
-
This work offers a catalytic approach to convergent ketone assembly based upon formal and tandem C-H insertion of diazoalkanes in the presence of limiting amounts of monomeric formaldehyde, which is easily generated as a gas by thermolysis of the inexpensive and abundant paraformaldehyde (~30 USD/kg). The method forms di-, tri-, and even tetrasubstituted acetones with high efficiency, and it has streamlined a synthesis of (-)-dihydrocuscohygrine in which the absolute stereochemistry of a proline-based starting material is preserved. Assisted by the advent of new protocols for hydrazone oxidation, we also provide full details on handling non-carbonyl-stabilized diazo compounds.
- Wommack, Andrew J.,Kingsbury, Jason S.
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p. 10573 - 10587
(2013/11/19)
-
- Synthesis of versatile bifunctional derivatives of chiral diamines obtained through anchimerically assisted nucleophilic substitution reactions on diastereomeric phenylprolinols
-
Diastereomeric [(S)-1-benzylpyrrolidin-2-yl]-(R)-[(phenyl)- methanamine] and [(S)-1-benzylpyrrolidin-2-yl]-(S)-[(phenyl)methanamine], were synthesized by selective internal backside nucleophilic substitution of the corresponding activated phenylprolinols. X-Ray diffraction structures of crystalline acetamide derivatives confirmed the anticipated stereochemistry for a SNib reaction mechanism. In order to apply this reaction to the synthesis of bifunctional analogs, a series of fragments such as a thiourea moiety and sulfonamide functions were introduced for the functionalization of the primary amino group in the substrate, obtaining more stable and potentially useful derivatives.
- Vargas-Caporali, Jorge,Cruz-Hernandez, Carlos,Juaristi, Eusebio
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p. 1275 - 1300
(2013/08/23)
-
- Synthesis of l-prolinol substituted novel optically active phthalocyanines
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The novel optically active Pc-4 (neutral) and Pc-5 (ionic), zinc(II) phthalocyanines having four N-benzyl protected l-prolinol unit were synthesized. l-prolinol has binucleophilic character and can be anchored to phthalonitrile derivative from both nitrogen and oxygen atoms. In order to overcome this problem and to enhance the solubility of phthalonitrile (S)-(-)-3 and the target phthalocyanines, the nitrogen atom of l-prolinol was first protected with benzyl chloride. All the compounds were characterized by 1H and 13C NMR, MALDI-TOF MS, IR, UV-vis, and Circular Dichroism (CD) spectroscopy. Pc-4 is highly soluble in most common organic solvents, whereas ionic Pc-5 is soluble in water. The CD results showed that the chiral information was transferred from the peripheral chiral l-prolinol side chains to the phthalocyanine chromophore at the molecular level.
- Karaca, Hüseyin,Sezer, Serdar,Tanyeli, Cihangir
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experimental part
p. 100 - 105
(2011/12/15)
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- The synthesis of piperidine nucleoside analogs - A comparison of several methods to access the introduction of nucleobases
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This work deals with the synthesis of piperidine and hydroxypiperidine analogs of nucleosides. Starting from commercially available 3-hydroxypiperidine, proline or 4-hydroxyproline, a series of piperidine derivatives of both purine and pyrimidine nucleobases was prepared. Various methods of nucleobase attachment were evaluated. The prepared compounds were tested for cytostatic, antibacterial, and antiviral properties but no significant activity was found.
- Kova?ková, Soňa,Dra?ínsky, Martin,Rejman, Dominik
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p. 1485 - 1500
(2011/04/15)
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- N-benzyl-protection of amino acid derivatives by reductive alkylation with α-picoline-borane
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A convenient method for N-protection of amino acid derivatives with a benzyl group by reductive alkylation of amino acid derivatives with α-picoline-borane is described. Amino acid esters or amino alcohols were treated with aryl aldehydes in methanol/acetic acid in the presence of -picoline-borane to give N-benzyl-protected amino acid derivatives in good yields. Georg Thieme Verlag Stuttgart - New York.
- Kawase, Yasushi,Yamagishi, Takehiro,Kutsuma, Teruo,Kataoka, Tadashi,Ueda, Kimio,Iwakuma, Takeo,Nakata, Tadashi,Yokomatsu, Tsutomu
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experimental part
p. 1673 - 1677
(2010/06/22)
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- Asymmetric addition of terminal alkynes to n-(Diphenylphosphinoyl)imines promoted by stoichiometric amounts of a proline-derlved ss-amino alcohol
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A new synthetic methodology for the preparation of optically active propargylamines is described. The alkynylation of aromatic, heteroaromatic, aliphatic and α,β-unsaturated N-(di-phenylphosphinoyl)imines was investigated by using dieth-ylzinc and a proline-derived β-amino alcohol, N-(Diphenylphosphinoyl)-protected propargylic amines can be synthesized in high yields and with good to excellent: enantio-selectivities.
- Yan, Wenjin,Mao, Bin,Zhn, Shaoqun,Jiang, Xianxing,Liu, Zhongli,Wang, Rui
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supporting information; experimental part
p. 3790 - 3794
(2009/12/07)
-
- Synthesis and utilization of trifluoromethylated amino alcohol ligands for the enantioselective Reformatsky reaction and addition of diethylzinc to N-(diphenylphosphinoyl)imine
-
A series of trifluoromethylated amino alcohol ligands, which had been designed and conveniently prepared, were successfully applied in the enantioselective Reformatsky reaction and addition of diethylzinc to N-(diphenylphosphinoyl)imine, respectively. The influence of the substituents on C-3 position and the amino moiety on the enantioselectivity has been carefully investigated. In the best cases, ligand 1b exhibited good selectivity for the enantioselective Reformatsky reaction in 86% ee and ligand 12d provided excellent enantioselectivity in the addition of diethylzinc to N-(diphenylphosphinoyl)imine with 95% ee.
- Xu, Xiu-Hua,Qiu, Xiao-Long,Qing, Feng-Ling
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p. 7353 - 7361
(2008/12/20)
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- Highly efficient copper-catalyzed N-arylation of nitrogen-containing heterocycles with aryl and heteroaryl halides
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(Chemical Equation Presented) New (S)-pyrrolidinylmethylimidazole ligands (4a-c) have been readily synthesized in a straightforward fashion from least expensive starting materials in short steps in high yields. Relatively mild and highly efficient Cul-catalyzed N-arylation procedures for imidazoles with aryl and heteroaryl bromides or chlorides have been developed in the presence of 4a and Cs2CO3. It is important to note that the protocol could tolerate functional groups such as ester, nitrile, nitro, ketone, free hydroxyl, and free primary amine on the aryl halide. The protocol could also be applicable to other π-electron-rich nitrogen heterocycles (pyrrole, pyrazole, indole, benzimidazole, and triazole), affording the N-arylazoles in good to excellent yields.
- Zhu, Liangbo,Cheng, Liang,Zhang, Yuxi,Xie, Rugang,You, Jingsong
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p. 2737 - 2743
(2008/02/05)
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- Exploiting π shielding interactions of η6 arene chromium (0) complexes: New auxiliaries derived from the biogenic chiral pool
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A family of highly selective chiral auxiliaries containing arene chromium (0) complexes has been prepared using biogenic precursors from the chiral pool. The systems, derived from isomannide, prolinol, and xylofuranose were applied to the asymmetric Diels-Alder reaction of derived acrylate esters. Factors influencing stereoselectivity with the auxiliaries have been investigated and delineated including the impact of mixed ligands on the chromium (0) complex. Under optimal conditions, the auxiliaries give >95% e.e. and 98:2 exo:endo ratio in cycloaddition with cyclopentadiene.
- Li, Jane,Xie, Longfei,Guzel, Mustafa,Heaton, Steven B.,Ma, Dong,Kallmerten, Amy E.,Jones, Graham B.
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p. 5459 - 5473
(2008/03/12)
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- Polymer-supported β-amino thioesters as catalysts for the enantioselective addition of diethylzinc to aldehydes
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A series of novel polymer-supported thioesters were prepared and found to be effective catalysts for the enantioselective addition of diethylzinc to benzaldehyde. These catalysts gave 1-phenylpropanol in up to 86% ee. The catalysts were fully recyclable and could be used in subsequent additions with retention of the enantioselectivity and efficiency levels.
- Eriksen, Heidi S.,Oyaga, Sandra Cotes,Sherrington, David C.,Gibson, Colin L.
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p. 1235 - 1238
(2007/10/03)
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- Exploiting π-shielding interactions: A highly selective chiral auxiliary derived from a biogenic building block
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A chiral auxiliary template, designed on the basis of π-shielding capability has been prepared from readily available L-proline. Cycloaddition to an acrylate derivative gave high endo preference, and diastereoselectivity as high as 99% was attainable. The electronic factors contributing to selectivity were probed, and the technology successfully applied to a polymer supported variant.
- Xie, Longfei,Jones, Graham B.
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p. 3579 - 3582
(2007/10/03)
-
- Synthesis of N-(dialkylaminoalkyl)alcohols by homogeneously catalyzed hydrogenolysis of cyclic N,O-acetals
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The homogeneously catalyzed hydrogenation of 1,3-oxazolidines affording unsymmetrically substituted 2-N-(dialkylamino)ethanols is reported showing for the first time that Rh(I) catalysts based on chelating diphosphines can be advantageous for this reaction.
- Tararov, Vitali I.,Kadyrov, Renat,Riermeier, Thomas H.,B?rner, Armin
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p. 375 - 380
(2007/10/03)
-
- Synthesis of the bicyclic core of pumiliotoxins
-
The bicyclic core of the pumiliotoxins was synthesized in nine to eleven steps starting from L-(-)-proline. This chiral pool starting material was initially converted into an optically active 2-vinylpyrrolidine by standard operations. The first key step allowed the generation of a nine-membered ring lactam by means of a zwitterionic aza-Claisen rearrangement. The 1,4 chirality transfer was found to be low, but the double bond of the azoninone was generated with an exclusive trans configuration in a planar-S arrangement. The mixture of diastereomers thus obtained was immediately epoxidized; the planar chiral information could be completely used to build up new stereogenic centers. Subsequent ring closure under hydrogenolytic conditions resulted in the formation of the bicyclic core with a bridgehead of defined configuration. The hydroxyl group of that material could be protected as a TBS ether, or alternatively a sequence of a Swern oxidation and subsequent methyl Grignard addition gave the complete bicyclic framework with low C8 diastereoselectivity. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Sudau, Alexander,Muench, Winfried,Bats, Jan-W.,Nubbemeyer, Udo
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p. 3304 - 3314
(2007/10/03)
-
- PENEM DERIVATIVES AND ANTIMICROBIAL AGENT CONTAINING THE SAME
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A penem derivative represented by the following formula (I): wherein R1represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted alkenylthio group, a substituted or unsubstituted aralkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic thio group, a substituted or unsubstituted acylthio group, a mercapto group or a hydrogen atom, and R2represents a hydrogen atom or a carboxyl-protecting group; or a pharmacologically acceptable salt thereof. The compound (I) exhibits strong antibacterial activities, and especially, shows strong activities against MRSA. It is therefore useful not only as a general antibacterial agent but also as an antibacterial agent for MRSA against which no general antibacterial agents are recognized to be effective.
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- Photochemical reaction between tertiary allylic amines and chromium carbene complexes: Synthesis of lactams via a zwitterion aza cope rearrangement
-
Photolysis of chromium carbene complexes in the presence of tertiary allylic amines resulted in a zwitterionic aza Cope rearrangement to produce unsaturated lactams in fair yield.
- Deur, Christopher J.,Miller, Michael W.,Hegedus, Louis S.
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p. 2871 - 2876
(2007/10/03)
-
- Reaction of (R)-pantolactone esters of alpha-bromoacids with amines. A remarkable synthesis of optically active alpha-amino esters
-
(R)-Pantolactone esters of racemic α-bromo acids react with amines to give α-amino esters having the (S)-configuration at the α-carbon in yields which are considerably greater than the 50% expected on the basis of a simple S(N)2 displacement reaction.
- Koh,Ben,Durst
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p. 4473 - 4476
(2007/10/02)
-
- Asymmetric Synthesis Using Chirally Modified Borohydrides. Part 2. Enantioselective Reduction of Ketones with Polymeric (S)-Prolinol-Borane Reagent
-
Chiral polymeric reagents have been prepared from polymeric (S)-prolinols and borane and used in the enantioselective reduction of a series of prochiral ketones under various conditions.Reductions with these polymeric reagents are shown to give alcohols of reasonably good optical purity (up to 80percent).The results are compared to those obtained with (S)-N-benzylprolinol-borane complex which is a soluble model reagent.
- Itsuno, Shinichi,Ito, Koichi,Hirao, Akira,Nakahama, Seiichi
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p. 2887 - 2893
(2007/10/02)
-