- 4,4′-Trimethylenedipiperidine, a safe and greener alternative for piperidine, catalyzed the synthesis of N-methyl imines
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A practical and facile synthesis of various N-methyl imines, versatile scaffolds, was conducted at 85?°C using 4,4′-trimethylenedipiperidine as a safe and green catalyst. This reagent is a commercially available solid and can be handled easily. It has high thermal stability, low toxicity, and good solubility in green solvents such as water and ethanol. The regenerated catalyst demonstrated stable activity after several recycle runs, and any changes were detected in its chemical structure by 1H NMR monitoring. The novelty of the current work is that the 4,4′-trimethylenedipiperidine can act as a promising alternative for piperidine in organic reaction at higher temperatures due to its broad liquid range temperature, thermal stability, acceptor/donor hydrogen bond property, and other unique merits. Furthermore, the current protocol avoids waste generation in the workup process, which is a drawback in most previous reported procedures.
- Gorjian, Hayedeh,Khaligh, Nader Ghaffari
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- Design, Synthesis, and Biological Evaluation of Novel 3-Aminomethylindole Derivatives as Potential Multifunctional Anti-Inflammatory and Neurotrophic Agents
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The development of multifunctional molecules that are able to simultaneously interact with several pathological components has been considered as a solution to treat the complex pathologies of neurodegenerative diseases. Herein, a series of aminomethylindole derivatives were synthesized, and evaluation of their application for antineuroinflammation and promoting neurite outgrowth was disclosed. Our initial screening showed that most of the compounds potently inhibited lipopolysaccharide (LPS)-stimulated production of NO in microglial cells and potentiated the action of NGF to promote neurite outgrowth of PC12 cells. Interestingly, with outstanding NO/TNF-α production inhibition and neurite outgrowth-promoting activities, compounds 8c and 8g were capable of rescuing cells after injury by H2O2. Their antineuroinflammatory effects were associated with the downregulation of the LPS-induced expression of the inflammatory mediators inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Western blotting and immunofluorescence assay results indicated that the mechanism of their antineuroinflammatory actions involved suppression of the MAPK/NF-κB signal pathways. Further studies revealed that another important reason for the high comprehensive antineuroinflammatory activity was the anti-COX-2 capabilities of the compounds. All these results suggest that the potential biochemical multifunctional profiles of the aminomethylindole derivatives provide a new sight for the treatment of neurodegenerative diseases.
- Wang, Wei-Wei,Liu, Ting,Lv, Yu-Meng,Zhang, Wu-Yang,Liu, Zhi-Gang,Gao, Jin-Ming,Li, Ding
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p. 1593 - 1605
(2021/05/31)
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- Enantioselective Reductive Coupling of Imines Templated by Chiral Diboron
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We herein report a general, practical, and highly efficient method for asymmetric synthesis of a wide range of chiral vicinal diamines via reductive coupling of imines templated by chiral diboron. The protocol features high enantioselectivity and stereospecificity, mild reaction conditions, simple operating procedures, use of readily available starting materials, and a broad substrate scope. The method signifies the generality of diboron-enabled [3,3]-sigmatropic rearrangement.
- Chen, Dongping,Li, Kaidi,Tang, Wenjun,Xu, Guangqing,Xu, Ronghua,Zhou, Mingkang
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supporting information
p. 10337 - 10342
(2020/07/04)
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- Stable carbamate pathway towards organic-inorganic hybrid perovskites and aromatic imines
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Methyl ammonium methyl carbamate (MAC), formulated as CH3NH3+CH3NHCO2-, was synthesized by reacting liquid methylamine with supercritical CO2, and its structure was refined by single-crystal X-ray diffraction. MAC is a white crystalline salt and is as reactive as methylamine, and is a very efficient alternative to toxic methylamine. We were able to produce hybrid perovskite MAPbI3 (MA = methyl ammonium) by grinding MAC with PbI2 and I2 at room temperature, followed by storing the mixed powder. Moreover, this one-pot method is easily scalable for the large-scale synthesis of MAPbI3 in a small vessel. We have also investigated the reactivity of MAC towards aromatic aldehydes in the absence of solvent. The solventless reactions afforded imines as exclusive products with over 97% yield, which show higher selectivity than the methylamine-based synthesis. Complete conversions were typically accomplished within 3 h at 25 °C. The results of this study emphasize the importance of solid carbamates such as MAC to develop an environmentally friendly process for the synthesis of various amine-based materials on the industrial scale.
- Hur, Nam Hwi,Kim, Sun Joo,Lee, Byeongno,Lee, Kyu Hyung,Lim, Byung Wook,Nam, Wonwoo,Park, Hee Sun,Park, Young Jun
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p. 38055 - 38062
(2020/11/02)
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- Epoxide-Mediated Stevens Rearrangements of α-Amino-Acid-Derived Tertiary Allylic, Propargylic, and Benzylic Amines: Convenient Access to Polysubstituted Morpholin-2-ones
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A new strategy has been established for the synthesis of polysubstituted morpholin-2-ones through Stevens rearrangements of tertiary amines via in situ activation with epoxides. A range of α-amino acid-derived tertiary allylic, propargylic, and benzylic amines reacted with epoxides in the presence of zinc halide catalysts to afford structurally diverse allyl-, allenyl-, and benzyl-substituted morpholin-2-ones, respectively, in moderate-to-good yields with high regioselectivity. The process involves [2,3]- and [1,2]-Stevens rearrangements of quaternary ammonium ylide intermediates and constitutes a very convenient method to prepare polysubstituted morpholin-2-ones through tandem formation of C?N, C?O, and C?C bonds. Moreover, replacing epoxides with aziridines permitted the synthesis of polysubstituted piperazin-2-ones.
- Jin, You-Xiang,Yu, Bang-Kui,Qin, Si-Ping,Tian, Shi-Kai
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supporting information
p. 5169 - 5172
(2019/03/28)
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- Mechanosynthesis of N-methyl imines using recyclable imidazole-based acid-scavenger: In situ formed ionic liquid as catalyst and dehydrating agent
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1,1′-(1,4-Butanediyl)bis(imidazole) was prepared by a modified method and its application as an efficient promoter was demonstrated for the mechanosynthesis of N-methyl imines using ball milling as a non-conventional process under solvent-free conditions. In this new protocol design, the bis-imidazole acted as a recyclable acid-scavenging agent. This efficient approach to the N-methyl imines displays a combination of the synthetic virtues of a non-conventional condensation reaction with ecological benefits and convenience of a facile mechanosynthetic process. The current method has advantages such as reduced waste by avoiding solvent, exclusion of hazardous materials during the reaction, elimination of handling an anhydrous gas in an evacuated container or a solution of methylamine in ethanol, good yields for relatively unreactive benzaldehydes containing electron-donating substituents, short reaction times, and metal- and acid-free conditions. Furthermore, the promoter was easily regenerated and reused several times with no significant loss of activity.
- Khaligh, Nader Ghaffari,Ling, Ong Chiu,Mihankhah, Taraneh,Johan, Mohd Rafie,Ching, Juan Joon
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p. 194 - 199
(2018/12/04)
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- Method for synthesizing imine by catalytic oxidation of asymmetric secondary amine in presence of visible light
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The invention belongs to the technical field of chemical engineering and pharmaceutical industry, and particularly relates to a method for synthesizing imine by catalytic oxidation of asymmetric secondary amine in the presence of visible light. With aza-metalloporphyrin containing sulfur as a visible light catalyst, 1,8-diazabicycloundecene-7-alkene as an auxiliary agent, and oxygen as an oxidant,asymmetric secondary amine is subjected to catalytic oxidation under irradiation of visible light of lambda being larger than or equal to 420nm, so as to obtain the oxidation product imine. A new andefficient imine production way is provided.
- -
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Paragraph 0025-0026; 0060-0064
(2018/11/22)
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- Synthesis of N-methyl imines in the presence of poly(N-vinylpyridine) as a reusable solid base catalyst by a mechanochemical process
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The synthesis of N-methyl imines was performed in the presence of catalytic amounts of poly(4-vinylpyridine) in high yields and rapidly at room temperature by a ball milling process. This new method has some advantages including good yields for relatively unreactive carbonyl compounds and short reaction times as well as being green in terms of avoiding the use of toxic reagents and solvents. The major advantage of this process is that the catalyst can be easily regenerated and reused several times without any significant loss of activity.
- Khaligh, Nader Ghaffari,Abbo, Hanna S.,Titinchi, Salam J. J.
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p. 901 - 910
(2017/02/10)
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- Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine-Functionalized Metal–Organic Frameworks
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Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal–organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2, Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2. Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
- Li, Xinle,Zhang, Biying,Tang, Linlin,Goh, Tian Wei,Qi, Shuyan,Volkov, Alexander,Pei, Yuchen,Qi, Zhiyuan,Tsung, Chia-Kuang,Stanley, Levi,Huang, Wenyu
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supporting information
p. 16371 - 16375
(2017/11/28)
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- Formal Ir-Catalyzed Ligand-Enabled Ortho and Meta Borylation of Aromatic Aldehydes via in Situ-Generated Imines
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The ligand-enabled development of ortho and meta C-H borylation of aromatic aldehydes is reported. It was envisaged that while ortho borylation could be achieved using tert-butylamine as the traceless protecting/directing group, meta borylation proceeds via an electrostatic interaction and a secondary interaction between the ligand of the catalyst and the substrate. These ligand-substrate electrostatic interactions and secondary B-N interactions provide an unprecedented controlling factor for meta-selective C-H activation/borylation.
- Bisht, Ranjana,Chattopadhyay, Buddhadeb
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supporting information
p. 84 - 87
(2016/01/25)
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- Thiazolidinones derived from dynamic systemic resolution of complex reversible-reaction networks
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A complex dynamic system based on a network of multiple reversible reactions has been established. The network was applied to a dynamic systemic resolution protocol based on kinetically controlled lipase-catalyzed transformations. This resulted in the formation of cyclized products, where two thiazolidinone compounds were efficiently produced from a range of potential transformations.
- Zhang, Yan,Ramstroem, Olof
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supporting information
p. 3288 - 3291
(2014/04/03)
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- Simple and efficient one-pot solvent-free synthesis of N-methyl imines of aromatic aldehydes
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A one-pot solvent-free synthesis of N-methyl imines in good to excellent yields was performed by grinding together aromatic aldehydes and methylamine hydrochloride in the presence of a base. The best yields were achieved when an excess of methylamine hydrochloride and inexpensive sodium hydrogen carbonate was used (usually in a molar ratio ArCHO/CH3NH2· HCl/NaHCO3 = 1:5:5), allowing the reaction to proceed for 1 h (in the case of aromatic aldehydes containing electron-withdrawing substituents) or overnight (in the case of electron-rich aldehydes). After a simple work-up (extraction with diethyl ether) the obtained products were mostly pure enough for spectral characterization. In this way, 31 N-methyl imines were prepared, among which eight were synthesized for the first time. Their structures were elucidated by spectral means (1H- and 13C-NMR, IR, MS) whenever it was possible. In the case of salicylaldehyde and 4-chlorobenzaldehyde, the synthesis of the corresponding imines was also conducted on a gram-scale with a 72% and 84% isolated yield, respectively. The present approach not only provides good to high yields, but also eliminates the disadvantages of the traditional synthesis of N-methyl imines, such as the use of hazardous solvents and more or less expensive catalysts and the necessity of work/handling with an anhydrous gas in pressurized containers.
- Radulovi?, Niko S.,Miltojevi?, Ana B.,Vuki?evi?, Rastko D.
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p. 257 - 270
(2013/05/09)
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- Highly enantioselective synthesis of tetrahydroquinolines via cobalt(II)-catalyzed tandem 1,5-hydride transfer/cyclization
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A chiral catalyst prepared from N,N′-dioxide and Co(BF 4)2·6H2O was applied in the asymmetric hydride transfer initiated cyclization reaction, giving optically active tetrahydroquinolines in good yields with high enantioselectivities under mild reaction conditions. Meanwhile, in light of the absolute configuration of the product, a possible working model was proposed to explain the origin of the activation and asymmetric induction.
- Cao, Weidi,Liu, Xiaohua,Wang, Wentao,Lin, Lili,Feng, Xiaoming
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supporting information; scheme or table
p. 600 - 603
(2011/04/15)
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- Application of sequential Cu(I)/Pd(0)-catalysis to solution-phase parallel synthesis of combinatorial libraries of dihydroindeno[1,2-c]isoquinolines
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Parallel solution-phase synthesis of combinatorial libraries of dihydroindenoisoquinolines employing a sequential Cu(I)/Pd(0)-catalyzed multicomponent coupling and annulation protocol was realized. The scope and limitations of the protocol with respect to the substitution pattern in the aryl ring of the indene core, as well as the N-substituent have been defined, revealing that the methodology is compatible with a wide-range of aliphatic linear, branched, and ester functionalized N-substituents. Unexpectedly, the formation of regioisomers featuring a 1,2,3-contiguous substitution pattern in the aromatic ring of the indene core was observed. Three distinct combinatorial libraries with a total of 111 of members were synthesized, and 80 highly substituted dihydroindenoisoquinolines structurally related to known medicinal agents including some consisting of mixtures of two regioisomers were made available for biological activity testing.
- Kumar, Sarvesh,Painter, Thomas O.,Pal, Benoy K.,Neuenswander, Benjamin,Malinakova, Helena C.
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body text
p. 466 - 477
(2011/11/06)
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- Catalytic intermolecular hetero-dehydro-diels-alder cycloadditions: Regioand diasteroselective synthesis of 5,6-dihydropyridin-2-ones
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A novel catalyzed intermolecular heterodehydro-Diels-Alder reaction between push-pull 1,3-dien-5-ynes and aldimines or silylaldimines is reported. The sequence is promoted both by gold(I) or silver(I) catalysts and leads to the diastereo- and regioselective formation of 5,6- dihydropyridin-2-ones.
- Fernandez-Garcia, Jesus Manuel,Fernandez-Rodriguez, Manuel A.,Aguilar, Enrique
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supporting information; experimental part
p. 5172 - 5175
(2011/12/04)
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- Efficient synthesis of new 4-arylideneimidazolin-5-ones related to the GFP chromophore by 2+3 cyclocondensation of arylideneimines with imidate ylides
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A 2+3 condensation of a wide assortment of Schiff bases, prepared from aromatic aldehydes and primary amines, with methyl (1-ethoxyethylideneamino) acetate allows convenient access to an extensive family of substituted 4-arylideneimidazolin-5-one analogues of the green fluorescent protein (GFP) chromophore. Georg Thieme Verlag Stuttgart · New York.
- Baldridge, Anthony,Kowalik, Janusz,Tolbert, Laren M.
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scheme or table
p. 2424 - 2436
(2010/09/06)
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- T-type calcium channel blockers: Spiro-piperidine azetidines and azetidinones - Optimization, design and synthesis
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A series of spiro-azetidines and azetidinones has been evaluated as novel blockers of the T-type calcium channel (CaV3.2) which is a new therapeutic target for the potential treatment of both inflammatory and neuropathic pain. Confirmation and
- Smith, Elizabeth M.,Sorota, Steve,Kim, Hyunjin M.,McKittrick, Brian A.,Nechuta, Terry L.,Bennett, Chad,Knutson, Chad,Burnett, Duane A.,Kieselgof, Jane,Tan, Zheng,Rindgen, Diane,Bridal, Terry,Zhou, Xiaoping,Jia, Yu-Ping,Dong, Zoe,Mullins, Debbie,Zhang, Xiaoping,Priestley, Tony,Correll, Craig C.,Tulshian, Deen,Czarniecki, Michael,Greenlee, William J.
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scheme or table
p. 4602 - 4606
(2010/10/02)
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- Gamma-lactams-A novel scaffold for highly potent and selective α7 nicotinic acetylcholine receptor agonists
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A novel class of α7 nicotinic acetylcholine receptor (nAChR) agonists has been discovered through high-throughput screening. The cis γ-lactam scaffold has been optimized to reveal highly potent and selective α7 nAChR agonists with in vitro activity and selectivity and with good brain penetration in mice.
- Enz, Albert,Feuerbach, Dominik,Frederiksen, Mathias U.,Gentsch, Conrad,Hurth, Konstanze,Mueller, Werner,Nozulak, Joachim,Roy, Bernard L.
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scheme or table
p. 1287 - 1291
(2009/10/02)
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- Novel pyrrolidine ureas as C-C chemokine receptor 1 (CCR1) antagonists
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Monocyte infiltration is implicated in a variety of diseases including multiple myeloma, rheumatoid arthritis, and multiple sclerosis. C-C chemokine receptor 1 (CCR1) is a chemokine receptor that upon stimulation, particularly by macrophage inflammatory protein 1a (MIP-1a) and regulated on normal T-cell expressed and secreted (RANTES), mediates monocyte trafficking to sites of inflammation. High throughput screening of our combinatorial collection identified a novel, moderately potent CCR1 antagonist 3. The library hit 3 was optimized to the advanced lead compound 4. Compound 4 inhibited CCR1 mediated chemotaxis of monocytes with an IC50 of 20 nM. In addition, the compound was highly selective over other chemokine receptors. It had good microsomal stability when incubated with rat and human liver microsomes and showed no significant cytochrome P450 (CYP) inhibition. Pharmacokinetic evaluation of the compound in the rat showed good oral bioavailability.
- Merritt, J. Robert,Liu, Jinqi,Quadros, Elizabeth,Morris, Michelle L.,Liu, Ruiyan,Zhang, Rui,Jacob, Biji,Postelnek, Jennifer,Hicks, Catherine M.,Chen, Weiqing,Kimble, Earl F.,Rogers, W. Lynn,O'Brien, Linda,White, Nicole,Desai, Hema,Bansal, Shalini,King, George,Ohlmeyer, Michael J.,Appell, Kenneth C.,Webb, Maria L.
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supporting information; experimental part
p. 1295 - 1301
(2009/12/07)
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- Synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-dione derivatives
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A preparative procedure for the synthesis of 2-alkyl-1-aryl-1,2- dihydrochromeno[2,3-c]pyrrole-3,9-diones from methyl 4-(o-hydroxyphenyl)-2,4- dioxobutanoate, aromatic aldehyde, and aliphatic amine is described.
- Vydzhak,Panchishin, S. Ya.
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experimental part
p. 2391 - 2397
(2009/05/30)
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- Cholinesterase inhibitors: SAR and enzyme inhibitory activity of 3-[ω-(benzylmethylamino)alkoxy]xanthen-9-ones
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In this work, we further investigated a previously introduced class of cholinesterase inhibitors. The removal of the carbamic function from the lead compound xanthostigmine led to a reversible cholinesterase inhibitors 3. Some new 3-[ω-(benzylmethylamino)alkoxy]xanthen-9-one analogs were designed, synthesized, and evaluated for their inhibitory activity against both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The length of the alkoxy chain of compound 3 was increased and different substituents were introduced. From the IC50 values, it clearly appears that the carbamic residue is crucial to obtain highly potent AChE inhibitors. On the other hand, peculiarity of these compounds is the high selectivity toward BuChE with respect to AChE, being compound 12 the most selective one (6000-fold). The development of selective BuChE inhibitors may be of great interest to clarify the physiological role of this enzyme and to provide novel therapeutics for various diseases.
- Piazzi, Lorna,Belluti, Federica,Bisi, Alessandra,Gobbi, Silvia,Rizzo, Stefano,Bartolini, Manuela,Andrisano, Vincenza,Recanatini, Maurizio,Rampa, Angela
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p. 575 - 585
(2008/03/12)
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- Efficient microwave-assisted solvent-free synthesis of N-substituted aldimines
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Neat non-volatile amines react with various aromatic aldehydes in the absence of any catalyst, solid support, or solvent, to give imines after a reaction time of eight minutes under microwave irradiation by a clean and very efficient process (yields: 75-100%). In the case of volatile amine, methylamine, 1,3-dimethylurea dispersed on montmorillonite K10 is used as an amine precursor to prepare the corresponding imines. Georg Thieme Verlag Stuttgart.
- Paquin, Ludovic,Hamelin, Jack,Texier-Boullet, Francoise
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p. 1652 - 1656
(2007/10/03)
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- LIGANDS OF MELANOCORTIN RECEPTORS AND COMPOSITIONS AND METHODS RELATED THERETO
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Compounds which function as melanocortin receptor ligands and having utility in the treatment of melanocortin receptor-based disorders. The compounds have the following structure (I): (R4)s (R 2)n N~ X1-X2 (CR1aCRlb)q 1~ N R1-lm 1 O R3 (I) including stereoisomers, prodrugs, and pharmaceutically acceptable salts thereof, wherein m, n, q, s, R1, R1a, R1b, R2, R3, R4, X1 X2 and X3 are as defined herein. Pharmaceutical compositions containing a compound of structure (I), as well as methods relating to the use thereof, are also disclosed.
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Page/Page column 75-76
(2010/02/11)
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- Oxidation of secondary amines by molecular oxygen and cyclohexanone monooxygenase
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Cyclohexanone monooxygenase from Acinetobacter calcoaceticus catalyzed the oxidation of tertiary and secondary amines to N-oxides and nitrones, respectively. The formation of a hydroxylamine intermediate was involved with secondary amines as starting substrates.
- Colonna, Stefano,Pironti, Vincenza,Carrea, Giacomo,Pasta, Piero,Zambianchi, Francesca
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p. 569 - 575
(2007/10/03)
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- Reactions of N-Benzyl- and N-Benzylidene-alkanolamines with Bromine: Formation of 1,3-Oxazolidines, 1,3-Oxazinanes, 4,5-Dihydro-1,3-oxazoles and 5,6-Dihydro-4H-1,3-oxazines
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N-Methylbenzylamines react with bromine in acetonitrile to form N-benzylidenemethylamines.Under similar conditions 2-benzylaminoethanols and 3-benzylaminopropan-1-ols afford 3-benzyl-2-phenyl-1,3-oxazolidines and 3-benzyl-2-phenyl-1,3-oxazinanes, respectively. 2-Benzylidineaminoethanols and 3-benzylideneaminopropan-1-ols likewise give 2-aryl-4,5-dihydro-1,3-oxazoles and 2-aryl-5,6-dihydro-4H-1,3-oxazines, respectively.When N-benzylidenemethylamine is treated with bromine in the presence of alcohols, benzaldehyde acetals are obtained.
- Goosen, Andre,McCleland, Cedric W.,Sipamla, Allworth M.
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p. 2221 - 2232
(2007/10/03)
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- Reactions of N-(arylsulfonoxy)-N-alkylbenzylamines with MeONa-MeOH. Steric effect on the structure of the imine-forming transition state
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Elimination reactions of N-(arylsulfonoxy)-N-alkylbenzylamines 1-5 with MeONa-MeOH have been studied kinetically. The elimination reactions are regiospecific, producing only corresponding benzylidenalkylamines. The rate equation for the reactions is kobs = k0 + k2[MeONa], indicating that the reactions proceed by competing solvolytic- and base-promoted pathways. The relative rates of elimination for the k2 and k0 pathways are 1, 0.67, 0.53, 0.35, and 0.27 for R = Me, Et, i-Pr, s-Bu, and t-Bu and 1, 4.1, 5.1, and 8.7 for R = Et, i-Pr, s-Bu, and t-Bu, respectively. For MeONa-promoted elimination from 1-5, Hammett ρ and kH/kD decrease but ρ1g and |β1g| increase with a bulkier alkyl substituent. However, the values for the solvolytic eliminations are nearly the same for all substrates and are similar to those for the base-promoted pathway, except for the ρ values, which have opposite signs. From these results, the changes in transition-state structure wrought by variation of N-alkyl substituents are assessed.
- Cho, Bong Rae,Pyun, Sang Yong
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p. 3920 - 3924
(2007/10/02)
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- Reactions of N-(Arylsulfonoxy)-N-benzylmethylamines with Sodium Methoxide in Methanol
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Reactions of N-(arylsulfonoxy)-N-benzylmethylamines (1) with MeONa in MeOH have been investigated.The eliminations are quantitative, producing only benzylidenemethylamines.The reactions are first order in substrate and first order in base, and an E2 mechanism is evident.Comparison of the rate data reveals that the arenesulfonates are better leaving groups than halogens in imine-forming elimination.For elimination from 1, ρ = 1.14, kH?kD = 3.6, ρlg = 1.30, and β1g = -0.43 have been calculated.Differences in the transition-sate characters for imine-forming eliminations from ArCH2N(Cl)CH3 and 1 have been intepreted in terms of changes in the leaving-group properties and base strength.
- Cho, Bong Rae,Pyun, Sang Yong,Kim, Tae Rin
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p. 8041 - 8044
(2007/10/02)
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- Benzylamines: Synthesis and evaluation of antimycobacterial properties
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The synthesis of benzylamines with various N-alkyl chains and substituents in the aromatic system as well as their evaluation on Mycobacterium tuberculosis H 37 Ra are described. The most active compounds in this test, N-methyl-3-chlorobenzylamine (MIC 10.2 μg/mL), N-methyl-3,5-dichlorobenzylamine (93, MIC 10.2 μg/mL), and N-butyl-3,5-difluorobenzylamine (MIC 6.4 μg/mL), also exhibited a marked inhibitory effect on Mycobacterium marinum and Mycobacterium lufu used for the determination of antileprotic properties. The combination of 93 with aminosalicylic acid, streptomycin, or dapsone exert marked supra-additive effects on M. tuberculosis H 37 Ra.
- Meindl,Von Angerer,Schonenberger,Ruckdeschel
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p. 1111 - 1118
(2007/10/02)
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- Photochemical Beckmann Rearrangements. Correspondence between Substituent Effect in Oximes and Oxaziridines
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The relative migratory tendencies of hydrogen and aryl groups in the photochemical Beckmann rearrangement of benzaldoximes 2a-c were compared with those in the photochemical rearrangement of 2-alkyl-3-aryloxaziridines 3a-f.The migratory tendencies depended on the nature of the aryl substituent and were similar in 2a-c and 3a-c, implying that the photochemical Beckmann rearrangement proceeds through an oxaziridine intermediate.A similar order of migratory tendencies was not found in the tert-butyloxaziridines 3d-f, presumably because of steric effects.
- Ogata, Yoshiro,Tagaki, Katsuhiko,Mizuno, Kiyohiko
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p. 3684 - 3687
(2007/10/02)
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