- Design, synthesis, and antiviral evaluation of purine-β-lactam and purine-aminopropanol hybrids
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Purine-β-lactam chimera were prepared as a novel class of hybrid systems through N-alkylation of 6-benzylamino- or 6-benzyloxypurine with (ω-haloalkyl)-β-lactams, followed by reductive ring opening of the β-lactam ring by LiEt3BH to provide an entry into the class of purine-aminopropanol hybrids. Both new types of hybrid systems were assessed for their antiviral activity and cytotoxicity, resulting in the identification of eight purine-β-lactam hybrids and two purine-aminopropanol hybrids as promising lead structures.
- D'Hooghe, Matthias,Mollet, Karen,De Vreese, Rob,Jonckers, Tim H. M.,Dams, Géry,De Kimpe, Norbert
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Read Online
- Trimethyl Borate-Catalyzed, Solvent-Free Reductive Amination
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Solvent-free reductive amination of aldehydes and ketones with aliphatic and aromatic amines in high-to-excellent yields has been achieved with sub-stoichiometric trimethyl borate as promoter and ammonia borane as reductant.
- Ramachandran, P. Veeraraghavan,Choudhary, Shivani,Singh, Aman
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p. 4274 - 4280
(2021/03/09)
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- Discovery of tert-amine-based RORγt agonists
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The nuclear receptor retinoic acid receptor-related orphan receptor gamma-t (RORγt) is a transcription factor regulating Th17 cell differentiation and proliferation from naive CD4+ T cells. Since Th17 cells have demonstrated the antitumor efficacy by eliciting remarkable activation of CD8+ T cells, RORγt agonists could be applied as potential small molecule therapeutics for cancer immunotherapy. Based on the previously reported RORγt agonist 1 and its resolved co-crystal structure, a series of new tertiary amines were designed, synthesized and biologically evaluated, yielding optimal moieties with improved chemical properties and biological responses. The combination of these optimal moieties resulted in identification of novel RORγt agonists such as 8b with further elevated RORγt agonism responses at a target-based level as well as in cell-based assays, which provided some structural knowledge for further optimization of RORγt agonists as small molecule therapeutics for cancer immunotherapy.
- Qiu, Ruomeng,Yu, Mingcheng,Gong, Juwen,Tian, Jinlong,Huang, Yafei,Wang, Yonghui,Xie, Qiong
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- Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group
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α-Nitrocinnamate underwent the conjugate addition of an active methylene compound such as nitroacetate, 1,3-dicarbonyl compound, or α-nitroketone, and the following ring closure afforded functionalized heterocyclic frameworks. The reaction of cinnamate with nitroacetate occurs via nucleophilic substitution of a nitro group by the O-attack of the nitronate, which results in isoxazoline N-oxide. This protocol was applicable to 1,3-dicarbonyl compounds to afford dihydrofuran derivatives, including those derived from direct substitution of a nitro group caused by O-attack of enolate. It was found the reactivity was lowered by an electron-withdrawing group on the carbonyl moiety. When α-nitroketone was employed as a substrate, three kinds of products were possibly formed; of these, only isoxazoline N-oxide was identified. This result indicates that the substituting ability of nitronate is higher than that of enolate for the direct SN2 substitution of a nitro group.
- Mukaijo, Yusuke,Nishiwaki, Nagatoshi,Yokoyama, Soichi
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- Efficient Co-Catalyzed Double Hydroboration of Nitriles: Application to One-Pot Conversion of Nitriles to Aldimines
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The commercially available and bench-stable Co(acac)2/dpephos system is employed as a precatalyst for selective and efficient room temperature hydroboration of organic nitriles with HBPin to produce a series of N,N-diborylamines [RN(BPin)2], which react in situ with aldehydes to give aldimines. Formation of aldimines from N,N-diborylamines does not require a dehydrating agent, is applicable to a wide range of N,N-diborylamine and aldehyde substrates and is highly chemoselective, being unaffected by various common functional groups, such as alkenes, alkynes, secondary amines, ketones, esters, amides, carboxylic acids, pyridines, nitriles, and nitro compounds. The overall transformation represents a synthetically valuable approach to aldimines from nitriles and can be performed in a sequential one-pot manner, tolerating ester, lactone, carboxamide and unactivated alkene functionalities.
- Gudun, Kristina A.,Slamova, Ainur,Hayrapetyan, Davit,Khalimon, Andrey Y.
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supporting information
p. 4963 - 4968
(2020/04/17)
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- Polyoxometalate catalyzed imine synthesis: Investigation of mechanistic pathways
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The syntheses of imines by oxidative coupling of primary alcohols and amines were achieved by using 2 molpercent polyoxometalate (POM) Na12[WZn3(H2O)2(ZnW9O34)2] (Zn–WZn3) catalyst in the presence of t-BuOK and di-oxygen with excellent conversion (up to 100percent) and selectivity (up to 100percent). Non-noble metal-based POM catalyst in the presence of base represents a new reaction protocol for the selective synthesis of imine from both aromatic and aliphatic primary amines with functional group tolerance. Control experiment shows the formation of di-oxygen bind Zn–WZn3 activated species. The electron-density of POM is mostly situated on the surface oxygen atoms of W–O–W bonds which can engage the alcoholic OH group and helps for the imine selectivity in the second step of imine synthesis.
- Adhikary, Subhasis D.,Mandal, Debaprasad
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supporting information
(2020/05/25)
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- Methyl-triflate-mediated dearylmethylation of: N -(arylmethyl)carboxamides via the retro-Mannich reaction induced by electrophilic dearomatization/rearomatization in an aqueous medium at room temperature
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We have developed a protocol for the dearylmethylation of N-(arylmethyl)carboxamides under metal-free conditions in an aqueous medium at room temperature. This protocol involves methyl triflate-mediated successive C-C and C-N bond cleavages (retro-Mannich reaction) induced by electrophilic dearomatization/rearomatization. The dearomatization/rearomatization strategy can be expected to inspire the development of novel transformations based on the C-C bond cleavage in an environmentally benign manner.
- Peng, Hui,Ma, Jinhui,Luo, Wenkun,Zhang, Guangwen,Yin, Biaolin
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supporting information
p. 2252 - 2256
(2019/05/17)
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- Organocatalytic Mukaiyama Mannich Reactions of 2,5-Bis(trimethylsilyloxy)furan
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The organocatalytic synthesis of densely substituted mono- and bis-?-lactams involving the Mukaiyama Mannich addition of 2,5-bis(trimethylsilyloxy)furan to imines is described. Use of a ditoluenesulfonylimide catalyst produces ?-lactams from monoaddition, whereas a more acidic catalyst (triflic acid) produces fused bis-lactams from double addition. Optimized organocatalytic conditions allow for the selective synthesis of either desired core as well as the one-pot, multicomponent assembly of the trisubstituted monolactams from aldehydes, amines, and bis-trimethylsilyloxyfuran. An examination of chiral acids found these organocatalysts to be highly active and diastereoselective in the monoaddition reaction, albeit with no enantioselectivity.
- Laws, Stephen W.,Howard, Sara Y.,Mato, Raquel,Meng, Shuyu,Fettinger, James C.,Shaw, Jared T.
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supporting information
p. 5073 - 5077
(2019/07/03)
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- METHOD OF PRODUCING ORGANOXYSILANE COMPOUND HAVING IMINE STRUCTURE
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PROBLEM TO BE SOLVED: To provide a method of producing organoxysilane compounds having a variety of imine structures at high yield, and high purity. SOLUTION: The method of producing an organoxysilane compound having an imine structure includes: reacting
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Paragraph 0072
(2019/12/25)
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- Biocatalytic N-Alkylation of Amines Using Either Primary Alcohols or Carboxylic Acids via Reductive Aminase Cascades
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The alkylation of amines with either alcohols or carboxylic acids represents a mild and safe alternative to the use of genotoxic alkyl halides and sulfonate esters. Here we report two complementary one-pot systems in which the reductive aminase (RedAm) from Aspergillus oryzae is combined with either (i) a 1° alcohol/alcohol oxidase (AO) or (ii) carboxylic acid/carboxylic acid reductase (CAR) to affect N-alkylation reactions. The application of both approaches has been exemplified with respect to substrate scope and also preparative scale synthesis. These new biocatalytic methods address issues facing alternative traditional synthetic protocols such as harsh conditions, overalkylation and complicated workup procedures.
- Ramsden, Jeremy I.,Heath, Rachel S.,Derrington, Sasha R.,Montgomery, Sarah L.,Mangas-Sanchez, Juan,Mulholland, Keith R.,Turner, Nicholas J.
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p. 1201 - 1206
(2019/01/21)
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- Selective aerobic oxidation of halides and amines with an inorganic-ligand supported zinc catalyst
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A practical, efficient and environmentally benign catalytic protocol for the oxidative cross-coupling reaction of halides with amines, oxidative self-coupling of amines and oxidation of halides was developed with inorganic-ligand supported ZnPOM (NH4)4[ZnMo6O18(OH)6] using molecular oxygen. This method mainly utilizes an inorganic polymolybdate ligand to support the Zn2+ ion, avoiding the use of complicated organic ligands.
- Wang, Jingjing,Zhai, Yongyan,Wang, Ying,Yu, Han,Zhao, Wenshu,Wei, Yongge
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p. 13323 - 13327
(2018/10/15)
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- Visible-Light-Driven Photocatalytic Oxidation of Organic Chlorides Using Air and an Inorganic-Ligand Supported Nickel-Catalyst Without Photosensitizers
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Engineering photoredox-triggered chemical transformation via visible light has been an emerging area in organic synthesis. However, most of the well-established photocatalysts are based upon either transition metal complexes involved with noble metals and organic ligands or photosensitive organic dyes, the development of pure inorganic molecular photocatalysts that could provide better stability and durability is greatly retarded. Herein we discover that the Anderson polyoxometalate (POM) Na4[NiMo6O18(OH)6] (1), which consists of pure inorganic framework built from a central NiII core supported by six MoVIO6 inorganic scaffold/ligands, can be used as a powerful photocatalyst. Upon irradiation with visible light (>400 nm), the compound can catalyze, in high efficiency, a wide range of reactions, including the oxidative cross-coupling reaction of chlorides with amines, as well as oxidation of chlorides using molecular oxygen, affording various imines, aldehydes, and ketones, respectively in high selectivity and good yields. Owing to the robust inorganic framework, this catalyst exhibits excellent stability during the catalysis and reusability with little loss of the catalytic activity, thus providing an alternative without use of complicated organic ligands and expensive noble metal-based photosensitizers.
- Yu, Han,Wang, Jingjing,Zhai, Yongyan,Zhang, Mengqi,Ru, Shi,Han, Sheng,Wei, Yongge
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p. 4274 - 4279
(2018/09/10)
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- Zinc(II)-Catalyzed Synthesis of Propargylamines by Coupling Aldimines and Ketimines with Alkynes
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A ZnII-catalyzed reaction between imines, which were derived from unactivated aldehydes or ketones and primary amines or α-amino acid esters, and terminal alkynes has led to the rapid and efficient formation of tri- and tetrasubstituted propargylamines (from aldimines and ketimines, respectively) in good to excellent yields. No additives or extra Lewis acid reagents were required for the imine-alkyne coupling reaction.
- Shehzadi, Syeda Aaliya,Saeed, Aamer,Lemière, Filip,Maes, Bert U. W.,Abbaspour Tehrani, Kourosch
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supporting information
p. 78 - 88
(2018/03/27)
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- Ligand-Controlled Inversion of Diastereo- and Enantioselectivity in Silver-Catalyzed Azomethine Ylide-Imine Cycloaddition of Glycine Aldimino Esters with Imines
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A highly diastereo- and enantioselective silver-catalyzed azomethine ylide-imine (AYI) cycloaddition reaction of glycine aldimino esters with imines was developed in which the Xing-Phos-controlled syn-selective or DTBM-Segphos-induced anti-selective AYI cycloaddition reaction could be applied to the synthesis of a variety of stereodivergent 1-alkyl-2,5-substituted imidazolidines with high yields and excellent enantioselectivities (up to 99% ee) as well as good diastereoselectivities (up to 99:1 dr) under mild reaction conditions.
- Yu, Bo,Yang, Ke-Fang,Bai, Xing-Feng,Cao, Jian,Zheng, Zhan-Jiang,Cui, Yu-Ming,Xu, Zheng,Li, Li,Xu, Li-Wen
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supporting information
p. 2551 - 2554
(2018/05/17)
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- Direct aziridination of nitroalkenes affording N-alkyl-C-nitroaziridines and the subsequent Lewis acid mediated isomerization to β-nitroenamines
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A mild and highly diastereoselective one-pot synthesis of trans-N-alkyl-C-nitroaziridines was achieved by treatment of nitroalkenes with aliphatic amines and N-chlorosuccinimide. Treatment of the obtained aziridines with a Lewis acid resulted in a facile ring opening reaction, accompanied by rearrangement and isomerization into functionalized (Z)-β-nitroenamines.
- Hao, Feiyue,Asahara, Haruyasu,Nishiwaki, Nagatoshi
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p. 5442 - 5445
(2017/11/06)
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- Harnessing Thin-Film Continuous-Flow Assembly Lines
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Inspired by nature's ability to construct complex molecules through sequential synthetic transformations, an assembly line synthesis of α-aminophosphonates has been developed. In this approach, simple starting materials are continuously fed through a thin-film reactor where the intermediates accrue molecular complexity as they progress through the flow system. Flow chemistry allows rapid multistep transformations to occur via reaction compartmentalization, an approach not amenable to using conventional flasks. Thin film processing can also access facile in situ solvent exchange to drive reaction efficiency, and through this method, α-aminophosphonate synthesis requires only 443 s residence time to produce 3.22 g h?1. Assembly-line synthesis allows unprecedented reaction flexibility and processing efficiency.
- Britton, Joshua,Castle, Jared W.,Weiss, Gregory A.,Raston, Colin L.
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supporting information
p. 10773 - 10776
(2016/07/27)
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- Diastereoselective Synthesis of and Mechanistic Understanding for the Formation of 2-Piperidinones from Imines and Cyano-Substituted Anhydrides
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2-Piperidinones are synthesized in a single step from imines and 2-cyano glutaric anhydrides. The reaction provides the products in good diastereoselectivity and generates a quaternary stereogenic center. Substitutions on the anhydride skeleton are well tolerated to provide 2-piperidinones with three stereogenic centers from a single transformation. The pertinent transition structures have also been computed using quantum mechanics and reveal the key interactions controlling the stereochemical outcome of the reaction.
- Di Maso, Michael J.,Snyder, Kevin M.,De Souza Fernandes, Fábio,Pattawong, Ommidala,Tan, Darlene Q.,Fettinger, James C.,Cheong, Paul Ha-Yeon,Shaw, Jared T.
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supporting information
p. 4794 - 4801
(2016/04/05)
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- Hydrogen peroxide/dimethyl carbonate: A green system for epoxidation of: N -alkylimines and N -sulfonylimines. One-pot synthesis of N -alkyloxaziridines from N -alkylamines and (hetero)aromatic aldehydes
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A green method for epoxidation of imines using an environmentally benign oxidant system, H2O2/dimethyl carbonate, was developed. N-Alkyloxaziridines were prepared in high yields from N-alkylamines and (hetero)aromatic aldehydes in one-pot fashion, whereas N-sulfonyloxaziridines have been prepared by using the same oxidant system and 5 mol% of Zn(OAc)2·2H2O as catalyst.
- Kra?em, Jamil,Ghedira, Donia,Ollevier, Thierry
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supporting information
p. 4859 - 4864
(2016/10/12)
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- Novel transition bimetal-organic frameworks: Recyclable catalyst for the oxidative coupling of primary amines to imines at mild conditions
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A novel type of transition bimetal-organic frameworks was described as a heterogeneous catalyst for the oxidative coupling of amines to imines under mild conditions, which was easily synthesized by the coordination assembly of manganese(ii) and cobalt(ii) with 1,3,5-benzenetricarboxylic acid (H3BTC) for the first time. The metal-organic framework material was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetry and N2 sorption. As an environmentally benign heterogeneous catalyst, the catalytic ability of the metal-organic framework material was then detected to be excellent for the tert-butyl hydroperoxide (TBHP) promoted direct oxidative coupling of benzylamines to imines in excellent yields (up to 100%) in methanol for 3 h. More importantly, it could be recycled up to six runs, while still maintaining its high catalytic activity.
- Ge, Danhua,Qu, Genlong,Li, Xinming,Geng, Kaiming,Cao, Xueqin,Gu, Hongwei
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p. 5531 - 5536
(2016/07/06)
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- Synthesis of 2-arylpyrroles via catalytic dehydrogenation of 2-aryl-1-pyrrolines in the presence of palladium-supported on alumina
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A convenient synthesis of 2-arylpyrroles from the catalytic dehydrogenation of 2-aryl-1-pyrrolines in the presence of commercial palladium-supported on alumina (Pd/Al2O3) is described. The reaction scope was tested for aryl substituents with different steric hindrances and electronic natures. The dehydrogenation reaction conditions such as temperature, reflux time and amount of catalyst, revealed to be highly dependent on the 2-aryl substituent group, moderate to high yields and selectivities being obtained in a reaction involving straightforward work-up and purification procedures. In addition, the synthesis of the corresponding 2-aryl-1-pyrroline starting materials, through the cyclisation reaction involving 4-chlorobutyronitrile and aryl Grignard reagents, is also reported.
- Figueira, Cláudia A.,Lopes, Patrícia S.,Gomes, Pedro T.
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p. 4362 - 4371
(2015/06/08)
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- Facile synthesis of litchi shaped cuprous oxide and its application in the aerobic oxidative synthesis of imines
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In the present work, uniform litchi shaped cuprous oxide (Cu2O) nanoaggregates were synthesized via a facile method by employing copper(ii) chloride, sodium hydroxide, ethylene glycol and ascorbic acid in the absence of surfactants at room temperature. With further increase of the reaction temperature, broken hollow copper nanoaggregates were obtained. The structure of a Cu2O nanoaggregate was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis and High Resolution Transmission Electron Microscopy (HRTEM). The as-obtained Cu2O nanoaggregates showed efficient catalytic activities in the aerobic oxidative synthesis of imines.
- Bai, Lei,Dang, Zheng
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p. 10341 - 10345
(2015/02/05)
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- Diastereoselective synthesis of γ- And δ-lactams from imines and sulfone-substituted anhydrides
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Sulfone-substituted γ- and δ-lactams have been prepared in a single step with high diastereoselectivity. Sulfonylglutaric anhydrides produce intermediates that readily decarboxylate to provide δ-lactams with high diastereoselectivity. Substituents at the 3- or 4-position of the glutaric anhydride induce high levels of stereocontrol. Sulfonylsuccinic anhydrides produce intermediate carboxylic acids that can be trapped as methyl esters or allowed to decarboxylate under mild conditions. This method has been applied to a short synthesis of the pyrrolizidine alkaloid (±)-isoretronecanol.
- Sorto, Nohemy A.,Di Maso, Michael J.,Munoz, Manuel A.,Dougherty, Ryan J.,Fettinger, James C.,Shaw, Jared T.
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p. 2601 - 2610
(2014/04/17)
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- Selective aerobic oxidation of alcohols to aldehydes, carboxylic acids, and imines catalyzed by a Ag-NHC complex
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Silver NHC catalysts have been developed for the selective oxidation of alcohols to aldehydes or carboxylic acids in the presence of BnMe3NOH or KOH under dry air. The aerobic oxidation conditions are mild, and the yield is excellent. Further tandem catalysis enables the one-pot synthesis of imines in excellent yield. Only 0.1 mol % of the catalyst is required.
- Han, Lei,Xing, Ping,Jiang, Biao
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supporting information
p. 3428 - 3431
(2014/07/21)
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- Gold-catalyzed oxidative rearrangement involving 1,2-acyl migration: Efficient synthesis of functionalized dihydro-γ-carbolines from α-(2-indolyl) propargylic alcohols and imines
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Smooth moves with a nifty side step: A gold-catalyzed transformation of α-(2-indolyl) propargylic alcohols with imines in the presence of the oxidant 8-isopropylquinoline N-oxide provided rapid access to highly functionalized dihydro-γ-carbolines (see scheme). The reaction mechanism is proposed to involve intermolecular trapping of an α-carbonyl gold carbenoid intermediate, followed by cyclization and a novel gold-assisted 1,2-acyl migration.
- Wang, Lu,Xie, Xin,Liu, Yuanhong
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supporting information
p. 13302 - 13306
(2014/01/06)
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- Aromatic aldehyde-catalyzed gas-phase decarboxylation of amino acid anion via imine intermediate: An experimental and theoretical study
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It is generally appreciated that carbonyl compound can promote the decarboxylation of the amino acid. In this paper, we have performed the experimental and theoretical investigation into the gas-phase decarboxylation of the amino acid anion catalyzed by the aromatic aldehyde via the imine intermediate on the basis of the tandem mass spectrometry (MS/MS) technique and density functional theory (DFT) calculation. The results show that the aromatic aldehyde can achieve a remarkable catalytic effect. Moreover, the catalytic mechanism varies according to the type of amino acid: (i) The decarboxylation of α-amino acid anion is determined by the direct dissociation of the C-C bond adjacent to the carboxylate, for the resulting carbanion can be well stabilized by the conjugation between α-carbon, C=N bond and benzene ring. (ii) The decarboxylation of non-α-amino acid anion proceeds via a SN2-like transition state, in which the dissociation of the C-C bond adjacent to the carboxylate and attacking of the resulting carbanion to the C=N bond or benzene ring take place at the same time. Specifically, for β-alanine, the resulting carbanion preferentially attacks the benzene ring leading to the benzene anion, because attacking the C=N bond in the decarboxylation can produce the unstable three or four-membered ring anion. For the other non-α-amino acid anion, the C=N bond preferentially participates in the decarboxylation, which leads to the pediocratic nitrogen anion.
- Xiang, Zhang
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p. 149 - 156
(2013/10/22)
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- Novel caffeic acid amide antioxidants: Synthesis, radical scavenging activity and performance under storage and frying conditions
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Twelve novel dihydro-caffeic acid amides were synthesised in good yields and fully characterised by 1H NMR, 13C NMR, and MS. Their radical scavenging activities were assessed by DPPH assay. Additionally, their abilities to protect polyunsaturated oils under accelerated storage and frying conditions were evaluated. All the new compounds possessed significantly higher radical scavenging activities than α-tocopherol and butylated hydroxytoluene (BHT). The radical scavenging activity of N-decyl-N-(3,5- dimethoxy-4-hydroxybenzyl)-3-(3,4-dihydroxyphenyl) propanamide was 1.7 and 4 times higher than α-tocopherol and BHT, respectively. At the end of the storage period, the respective amounts of hydroperoxides in canola oil triacylglycerols (CTAG) fortified with α-tocopherol and BHT was 6.1 and 1.4 times higher, respectively, than CTAG containing the amide. The frying test showed that CTAG containing N-decyl-N-benzyl-3-(3,4-dihydroxybenzyl) propanamide was 1.3, 1.4, and 1.6 times more stable compared to oil fortified with dihydro-caffeic acid, α-tocopherol and BHT, respectively, as assessed by the amounts of the total polar compounds. Moreover, these compounds were remarkably thermally stable, making them suitable for frying applications.
- Aladedunye, Felix,Catel, Yohann,Przybylski, Roman
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experimental part
p. 945 - 952
(2012/05/05)
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- Water-promoted one-pot vinylogous Mannich-type reaction of trimethylsilyloxyfuran
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Water, produced in situ during the formation of imines from aldehydes 1 and amines 2, is employed to promote the one-pot Mannich reaction of trimethylsilyloxyfuran 3a without addition of extra solvent or catalyst. This clean and quick reaction allows the obtention of a series of 5-substituted γ-butenolides 4 with good yields and modest diastereomeric ratio. A large panel of substituents is tolerated ranging from aliphatic chains to aromatic or heteroaromatic rings.
- Landelle, Grégory,Claraz, Aurélie,Oudeyer, Sylvain,Levacher, Vincent
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supporting information; experimental part
p. 2414 - 2416
(2012/06/01)
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- Merging constitutional and motional covalent dynamics in reversible imine formation and exchange processes
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The formation and exchange processes of imines of salicylaldehyde, pyridine-2-carboxaldehyde, and benzaldehyde have been studied, showing that the former has features of particular interest for dynamic covalent chemistry, displaying high efficiency and fast rates. The monoimines formed with aliphatic α,ω-diamines display an internal exchange process of self-transimination type, inducing a local motion of either "stepping-in- place" or "single-step" type by bond interchange, whose rate decreases rapidly with the distance of the terminal amino groups. Control of the speed of the process over a wide range may be achieved by substituents, solvent composition, and temperature. These monoimines also undergo intermolecular exchange, thus merging motional and constitutional covalent behavior within the same molecule. With polyamines, the monoimines formed execute internal motions that have been characterized by extensive one-dimensional, two-dimensional, and EXSY proton NMR studies. In particular, with linear polyamines, nondirectional displacement occurs by shifting of the aldehyde residue along the polyamine chain serving as molecular track. Imines thus behave as simple prototypes of systems displaying relative motions of molecular moieties, a subject of high current interest in the investigation of synthetic and biological molecular motors. The motional processes described are of dynamic covalent nature and take place without change in molecular constitution. They thus represent a category of dynamic covalent motions, resulting from reversible covalent bond formation and dissociation. They extend dynamic covalent chemistry into the area of molecular motions. A major further step will be to achieve control of directionality. The results reported here for imines open wide perspectives, together with other chemical groups, for the implementation of such features in multifunctional molecules toward the design of molecular devices presenting a complex combination of motional and constitutional dynamic behaviors.
- Kovaricek, Petr,Lehn, Jean-Marie
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experimental part
p. 9446 - 9455
(2012/07/14)
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- A study on the Kabachnik-Fields reaction of benzaldehyde, propylamine, and diethyl phosphite by in situ Fourier transform IR spectroscopy
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The phospha-Mannich condensation of benzaldehyde, n-propylamine, and diethyl phosphite carried out at 80°C in acetonitrile takes place via the imine (PhC=N-Pr) intermediate as suggested by in situ FT-IR spectroscopy. Copyright
- Keglevich, Gyoergy,Fehervari, Andras,Csontos, Istvan
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experimental part
p. 599 - 604
(2011/12/05)
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- Cationic palladacycles as catalyst precursors for phenyl acetylene polymerization
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Novel cationic palladacycles based on benzylidene-2,6- diisopropylphenylimines were prepared via C-H activation using Pd(CH 3CN)2Cl2 as metal precursor. The complexes were fully characterized by IR and NMR spectroscopy, mass spectrometry and elemental analysis. The cationic palladacycles were found to be active catalysts for the polymerization of phenylacetylene producing largely trans-cisoidal PPA.
- Mungwe,Swarts,Mapolie,Westman
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experimental part
p. 3527 - 3535
(2011/11/06)
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- A practical route to tertiary diarylmethylamides or -carbamates from imines, organozinc reagents and acyl chlorides or chloroformates
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A practical route to tertiary diarylmethylamides or -carbamates from imines, organozinc reagents and acyl chlorides or chloroformates is described. This route involves the formation of an imine, which is used without isolation, followed by its activation
- Le Gall, Erwan,Pignon, Antoine,Martens, Thierry
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experimental part
p. 997 - 1002
(2011/09/19)
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- Preparation of dialkyl 1-(Alkylamino)alkylphosphonates, alkyl [1-(Alkylamino)alkyl]phenylphosphinates and [1-(Alkylamino)alkyl] diphenylphosphine oxides via in situ generated iminium ions
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The reaction of trialkyl phosphites, dialkyl phenylphosphonites or alkyl diphenylphosphinites with N-alkylalkanimines in the presence of hydrogen chloride gives dialkyl 1-(alkylamino)alkylphosphonates, alkyl amino)alkyl]phenylphosphinates or [1-(alkylamino)alkyl]diphenylphosphine oxides respectively, via Arbusov-like reaction of iminium salts generated in situ from N-alkylalkanimines. This reaction is an alternative and competitive to known method of preparation based on the addition of H-P compounds to N-alkylalkanimines, because it gives higher yields, no heating is necessary, and the isolation of products is easy. Georg Thieme Verlag Stuttgart · New York.
- Goldeman, Waldemar,Soroka, Miroslaw
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experimental part
p. 2437 - 2445
(2010/09/04)
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- Synthesis of novel 2-alkoxy-3-amino-3-arylpropan-1-ols and 5-alkoxy-4-aryl-1,3-oxazinanes with antimalarial activity
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A variety of novel syn-2-alkoxy-3-amino-3-arylpropan-1-ols was prepared through LiAlH4-promoted reductive ring-opening of cis-3-alkoxy-4-aryl-β-lactams in Et2O. The latter γ-aminoalcohols were easily converted into cis-5-alkoxy-4-aryl-1,3- oxazinanes using formaldehyde in THF. Both series of compounds were evaluated against a chloroquine sensitive strain of Plasmodium falciparum (D10), revealing micromolar potency for almost all representatives. Eleven compounds exhibited antimalarial activity with IC50 values of ≤30 μM, and the majority of these compounds did not show cytotoxicity at the concentrations tested.
- D'hooghe, Matthias,Dekeukeleire, Stijn,Mollet, Karen,Lategan, Carmen,Smith, Peter J.,Chibale, Kelly,De Kimpe, Norbert
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body text
p. 4058 - 4062
(2009/12/28)
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- A regiospecific approach to N-alkylpyrazoles and the derived N-oxides using 5-endo-dig cyclisations of alkynyl nitrosamines
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5-endo-dig Cyclisations of N-nitroso derivatives of homopropargylic amines, catalysed by silver nitrate on silica gel proceed smoothly at ambient temperature in chlorinated solvents to give essentially quantitative yields of the corresponding pyrazole-N-oxides, deoxygenation of which gives excellent yields of the related N-alkylpyrazoles in a regiospecific manner. Georg Thieme Verlag Stuttgart.
- Hayes, Simon J.,Knight, David W.,O'Halloran, Mark,Pickering, Stuart R.
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experimental part
p. 2188 - 2190
(2009/04/07)
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- Cobalt-catalyzed carbonylation of N-alkylbenzaldimines to 'N-alkylphthalimidines' (=2,3-dihydro-1H-isoindol-1-ones) via tandem C-H activation and cyclocarbonylation
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The reaction of N-alkylbenzaldimines with carbon monoxide (CO) in the presence of cobalt (Co) catalysts resulted in the formation of N-alkylphthalimidines (Table 1). Their formation is proposed to occur by C-H activation of the aryl ring, migratory insertion of the hydride species into the benzaldimine functionality, CO coordination, and insertion into the Co-C bond, followed by reductive elimination of the N-alkylphthalimidine and regeneration of the starting Co species (Scheme 4). Deuterium (2H)-labeling NMR studies are consistent with this mechanism (Scheme 5).
- Funk, Jeffrey K.,Yennawar, Hemant,Sen, Ayusman
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p. 1687 - 1695
(2007/10/03)
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- Electrochemical oxidation of benzylic amines into the corresponding imines in the presence of catalytic amounts of KI
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Oxidation of various benzylic amines using an indirect electrochemical method was successfully carried out under very mild conditions to afford the corresponding imines in good yields. Our results show that, for this electrolytic system, the iodide ions play an important role as electron carriers. Copyright Taylor & Francis, Inc.
- Okimoto, Mitsuhiro,Takahashi, Yukio,Numata, Kaori,Nagata, Yuji,Sasaki, Gaku
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p. 1989 - 1995
(2007/10/03)
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- Reductive amination of aldehydes and ketones with sodium borohydride supported onto HZSM-5 zeolite under microwave irradiation in a solvent free system
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Sodium borohydride supported onto a HZSM-5 zeolite is presented as a general reducing agent for the reductive amination of aldehydes and ketones under microwave irradiation in solventless system. Copyright Taylor & Francis Inc.
- Oskooie, Hossein A.,Amiri, Somaih Solemani,Heravi, Majid M.,Ghassemzadeh, Mitra
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p. 2047 - 2050
(2007/10/03)
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- Preparation of benzolactams by Pd(OAC)2-catalyzed direct aromatic carbonylation
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We developed a new method for Pd(II)-catalyzed direct aromatic carbonylation in a phosphine-free catalytic system using Pd(OAc)2 and Cu(OAc)2 in an atmosphere of CO gas containing air. The carbonylation proceeded with ortho-palladation, inducing a remarkable site selectivity to afford a variety of five- or six-membered benzolactams from secondary ω-arylalkylamines, such as N-alkylbenzylamines or N-alkylphenethylamines. Copyright
- Orito, Kazuhiko,Horibata, Akiyoshi,Nakamura, Takatoshi,Ushito, Harumi,Nagasaki, Hideo,Yuguchi, Motoki,Yamashita, Satoshi,Tokuda, Masao
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p. 14342 - 14343
(2007/10/03)
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- Model compounds study on the network structure of polybenzoxazines
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The FT-IR and 1H NMR spectra of model dimers, having different molecular sizes and pKa, are investigated in order to understand the differences in the hydrogen-bonded network structures of polybenzoxazines. The correlation between the -OH...N intramolecular hydrogen-bonding interaction and benzoxazine functional groups in the asymmetric dimers is investigated by 1H NMR spectra. While the FT-IR spectra of the model dimers indicate that the nature of hydrogen bonding is closely related to the basicity of the amine constituent, the spectra of the corresponding polymers suggest the existence of different hydrogen-bonding interactions. The existence of phenolic linkage formation and the stability of the Mannich base structure during polymerization are investigated by a dimerization reaction. It is demonstrated that benzoxazines based upon extremely bulky amines do not develop desirable properties due to the extensive degradation process.
- Kim, Ho-Dong,Ishida, Hatsuo
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p. 8320 - 8329
(2007/10/03)
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- Synthesis of imines, diimines and macrocyclic diimines as possible ligands, in aqueous solution
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Although it is recognized that the presence of water is disadvantageous for imine synthesis, we demonstrate that such synthesis can be effective in completely aqueous media, without any catalyst and under mild conditions. Thus, arylaryl, aryl-alkyl, alkyl-aryl and alkyl-alkyl monoimines as well as a large variety of diimines are obtained by direct condensation of the corresponding carbonyl compounds and amines, in water. The same process is used to synthesize macrocyclic diimines starting from methylene, ethylene, trimethylene and tetramethylene glycol bis(2-formylphenyl ether) and ethylene-, trimethylene- and tetramethylene-diamine, some of these macrocycles being known for their chelating properties.
- Simion, Alina,Simion, Cristian,Kanda, Tadeshige,Nagashima, Satoko,Mitoma, Yoshiharu,Yamada, Tomoko,Mimura, Keisuke,Tashiro, Masashi
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p. 2071 - 2078
(2007/10/03)
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- Chemoselective debenzylation of N-benzyl tertiary amines with ceric ammonium nitrate
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Treatment of a range of N-benzyl tertiary amines with aqueous eerie ammonium nitrate results in N-debenzylation to afford the corresponding secondary amine. Chemoselective mono-W-debenzylation of N-benzyl tertiary amines is shown to occur in the presence of N-benzyl amides, O-benzyl ethers, O-benzyl esters, O-benzyl phenolates and 5-benzyl ethers. The Royal Society of Chemistry 2000.
- Bull, Steven D.,Davies, Stephen G.,Fenton, Carry,Mulvaney, Andrew W.,Shyam Prasad,Smith, Andrew D.
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p. 3765 - 3774
(2007/10/03)
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- Spin trapping chemistry of iminyl free radicals
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The iminyl radicals formed from hydrogen atom abstraction between tert-butoxyl radicals and benzylidene-N-alkyl-or N-arylamines were trapped by 2-methyl-2-nitrosopropane and investigated by EPR spectroscopy. The compounds investigated were benzylidene N-methyl, ethyl, 1-propyl, 1-butyl, 2-methylpropyl, 1-methylethyl, 1-methylpropyl, 1-ethylpropyl, 1-methylbutyl and cyclohexyl derivative and also benzylidene N-phenyl, 4-tolyl, 4-fluorophenyl, 4-methoxyphenyl, 4-chlorophenyl, 4-nitrophenyl and 4-trifluoromethylphenyl derivatives. In every case the iminyl nitroxide (aminoxyl) was produced in benzene at room temperature. The nitrogen hyperfine splitting constants were in the ranges 3.39-3.56 and 9.68-9.77 G for the iminyl and nitroxyl nitrogens, respectively, for the benzylidene-N-alkylamines and 3.60-3.77 and 8.45-9.15 G for the iminyl and nitroxyl nitrogens, respectively, for the benzylidene-N-arylamines. Very little evidence was found for hydrogen atom abstraction from the alkyl groups attached to the imine function. The absolute rate constant for hydrogen atom abstraction of the iminyl hydrogen was estimated to be 1.2 × 104 M-1 s-1 based on competitive experiments with addition of tert-butoxyl radicals to 2-methyl-2-nitrosopropane (1.5 × 106 M-1 s-1). This value is considerably slower than that for benzaldehyde (2.4 × 107 M-1 s-1).
- Janzen, Edward G.,Nutter, Dale E.
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p. 131 - 140
(2007/10/03)
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- Azaheteroalkene metathesis: Reaction of imines with molybdenum(VI) bis(imide) complexes
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Bis(imide) complexes (dme)Cl2Mo(=NR)2 (R = But, C6H3Pri2-2,6) and (ButO)2Mo(=NAr)2 (Ar = C6H3Pri2-2,6
- Cantrell, Gidget K.,Meyer, Tara Y.
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p. 1551 - 1552
(2007/10/03)
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- Synthesis of new azepino[3,4,5-cd]indole derivatives
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New 2-oxoazepino[3,4,5-cd]indole derivatives were formed by the reaction of the tosylate SKandF 98339 with N-alkyl and N-arylidenepropylamines in moderate yield.
- Hayes,Hayler,Walsgrove,Wicks
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p. 209 - 212
(2007/10/03)
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- Photolysis of 3-chloro-3-aryldiazirines in the presence of amines and allyl alcohol
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When photolysis of arylchlorodiazirines is performed in the presence of either alkyl- or allyl-substituted amines, either N-alkyl- or N-allyl-substituted amines result as the sole high-yield (64-93%) products. Photolysis in the presence of phenylally-lami
- Liu,Romashin,Venkatachalam
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p. 1961 - 1965
(2007/10/02)
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- Separation of Ring Polar and Resonance Effects on the Rate Constants for Uncatalyzed N-Arylidenepropylamine Formation in Methanol
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Rate constants are reported for the reaction of a series of 19 ring-substituted benzaldehydes with propylamine in methanol and in O-d-methanol at different temperatures and of three of them with 2-methoxyethylamine and 2,2-dimethoxyethylamine.The large di
- Toullec, Jean,Milin, Didier
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p. 2840 - 2847
(2007/10/02)
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- SYNTHESIS OF α-AMINONITRILES BY SELF-CATALYZED, STOICHIOMETRIC REACTION OF PRIMARY AMINES, ALDEHYDES, AND TRIMETHYLSILYL CYANIDE
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α-Aminonitriles can be prepared at room temperature in good yield by either the addition of a primary amine to a mixture aldehyde/trimethylsilyl cyanide (TMSCN) or by the addition of an aldehyde to a mixture amine/TMSCN.The reaction proceeds via the initi
- Leblanc, Jean-Pierre,Gibson, Harry W.
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p. 6295 - 6298
(2007/10/02)
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- Duality of the Permanganate Ion in the Oxidation of Imines. Oxidation of Imines to Amides
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The oxidation of imines with potassium permanganate in acetonitrile-water has been studied.The reaction gives the corresponding amide as the major product, in contrast to the oxidation of imines with potassium permanganate in methylene dichloride-water un
- Larsen, Jan,Jorgensen, Karl Anker,Christensen, Dorthe
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p. 1187 - 1190
(2007/10/02)
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- Intramolecular Base Catalysis in N-Benzylideneaniline Transimination by (Dimethylamino)alkylamines in Methanol
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The internal tertiary amino group in 2-(dimethylamino)ethylamine and 3-(dimethylamino)propylamine catalyzes proton transfer between nitrogen atoms of the gem-diamines formed in the course of the title reaction.
- Toullec, Jean,Razafindralambo, Romuald
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p. 1646 - 1647
(2007/10/02)
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