- Thermodynamic study for the stability of aromatic complexes formation derived from the reaction of 4-dimethyl amino benzaldehyde with diazotized dinitro aniline reagents
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This research includes the preparation of aromatic azoimine complexes resulting from the coupling reaction (4) of Schiff bases with diazotized dinitroaniline reagent. Ultraviolet spectra, infrared spectra, and melting points are among the most important p
- Al-Niemi, Mohammad Mahmoud Hussein Younes,Mohsin, Ahmed Hussein Ali
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p. 421 - 437
(2021/12/17)
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- In silico, in vitro and in vivo studies indicate resveratrol analogue as a potential alternative for neuroinflammatory disorders
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Inflammaging is known as an imbalance between pro-inflammatory and anti-inflammatory immune mechanisms, being related to the onset of neurological disorders, such as major depression and Alzheimer's disease. Considering the known disadvantages regarding the FDA approved drug to manage such illnesses, resveratrol emerges as a natural drug candidate, despite its low bioavailability. In this study, resveratrol analogues were evaluated for their capacity of inhibiting acetylcholinesterase in silico, in vitro, and in vivo. Molecular docking simulations pointed out RSVA1 and RSVA6 as potent inhibitors, even more than resveratrol. Ellman's assay demonstrated RSVA6 as capable of inhibiting 92.4% of the enzyme activity. Further, male Swiss mice were pretreated with RSVA6 (100 mg kg?1) 60 min before receiving scopolamine (1 mg kg?1). The Novel Recognition Object (NOR), Object Location (OLT), and Buried Pellet tests (BPL) demonstrated an RSVA6 neuroprotective effect. In the second round of tests, mice received a single intraperitoneal injection of lipopolysaccharide (0.5 mg kg?1) 24 h before treatment with RSVA6 (1, 10, and 100 mg kg?1). The Open Field (OFT), Tail Suspension (TST), and Splash tests (ST) were evaluated. LPS had no significant effect on the crossing and rearing number, indicating an association between the immobility time and anhedonia observed in the TST and ST, respectively, with depressive-like behavior. RSVA6 significantly reduced the depressive-like behavior triggered by LPS in the TST and ST. Altogether, our data suggest RSVA6 as a potential drug candidate for the treatment of neuroinflammatory conditions.
- Dutra, Rafael Cypriano,Goliatt, Priscila Vanessa Zabala Capriles,Marion, Gabriel Macedo,Meinel, Raissa Soares,Nunes, Vinicius Schmitz Pereira,da Silva, Adilson David,Fávero, Amanda,Menegasso, Jaíne Ferrareis,Raposo, Nádia Rezende Barbosa,de Assis, Pollyana Mendon?a
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- Catalyst- And solvent-free efficient access to: N -alkylated amines via reductive amination using HBpin
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A sustainable approach which works under catalyst- and solvent-free conditions for the synthesis of structurally diverse secondary amines has been uncovered. This one-pot protocol works efficiently at room temperature and is compatible with a wide range of sterically and electronically diverse aldehydes and primary amines. Notably, this simple process offers scalability, excellent functional group tolerance, chemoselectivity, and is also effective at the synthesis of biologically relevant molecules. This journal is
- Bauri, Somnath,Pandey, Vipin K.,Rit, Arnab
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supporting information
p. 3853 - 3857
(2020/07/27)
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- Main-Group-Catalyzed Reductive Alkylation of Multiply Substituted Amines with Aldehydes Using H2
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Given the growing demand for green and sustainable chemical processes, the catalytic reductive alkylation of amines with main-group catalysts of low toxicity and molecular hydrogen as the reductant would be an ideal method to functionalize amines. However, such a process remains challenging. Herein, a novel reductive alkylation system using H2 is presented, which proceeds via a tandem reaction that involves the B(2,6-Cl2C6H3)(p-HC6F4)2-catalyzed formation of an imine and the subsequent hydrogenation of this imine catalyzed by a frustrated Lewis pair (FLP). This reductive alkylation reaction generates H2O as the sole byproduct and directly functionalizes amines that bear a remarkably wide range of substituents including carboxyl, hydroxyl, additional amino, primary amide, and primary sulfonamide groups. The synthesis of isoindolinones and aminophthalic anhydrides has also been achieved by a one-pot process that consists of a combination of the present reductive alkylation with an intramolecular amidation and intramolecular dehydration reactions, respectively. The reaction showed a zeroth-order and a first-order dependence on the concentration of an imine intermediate and B(2,6-Cl2C6H3)(p-HC6F4)2, respectively. In addition, the reaction progress was significantly affected by the concentration of H2. These results suggest a possible mechanism in which the heterolysis of H2 is facilitated by the FLP comprising THF and B(2,6-Cl2C6H3)(p-HC6F4)2.
- Hoshimoto, Yoichi,Kinoshita, Takuya,Hazra, Sunit,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 7292 - 7300
(2018/06/01)
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- Conversion of aldimines to secondary amines using iron-catalysed hydrosilylation
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Iron-catalyzed hydrosilylation of imines to amines using a well-defined iron complex is reported. This method employs relatively mild conditions, by reaction of imine, (EtO)3SiH in a 1 : 2 ratio in the presence of 1 mol% precatalyst ([BIAN]Fe(η6-toluene), 3, BIAN = bis(2,6-diisopropylaniline)acenaphthene) at 70 °C. A broad scope of imines was readily converted into the corresponding secondary amines without the need for precatalyst activators.
- Saini, Anu,Smith, Cecilia R.,Wekesa, Francis S.,Helms, Amanda K.,Findlater, Michael
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supporting information
p. 9368 - 9372
(2019/01/03)
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- Stereoselective Synthesis of 3-(5-Benzoyl-1-methyl-1 H -pyrrol-2-yl)-2-azetidinone Derivatives via an in Situ Generated Ketene
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A short route toward β-lactams from tolmetin has been developed. In the key step, a ketene was generated on the C-2 of pyrrole ring and reacted with aromatic imines to form trans -β-lactams as the only observed products. The identification of the ketene was confirmed by reaction with the stable free radical TEMPO (TO·).
- Bananezhad, Behjat,Islami, Mohammad Reza
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supporting information
p. 1453 - 1456
(2017/07/22)
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- One-pot synthesis of trans-β-lactams from ferrocenylketene generated by thermal Wolff rearrangement
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A series of β-lactams containing the ferrocene moiety were synthesized through the Staudinger reaction between ferrocenylketene generated by the thermal Wolff rearrangement of the corresponding diazo ketone and various imines. The stereochemical outcome h
- Liu, Mingshun,Wang, Jian’an,Yuan, Xiaoxi,Jiang, Rong,Fu, Nanyan
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supporting information
p. 2369 - 2377
(2017/12/12)
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- Heterogeneous Catalytic Reductive Amination of Carbonyl Compounds with Ni-Al Alloy in Water as Solvent and Hydrogen Source
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The heterogeneous catalytic reductive amination of carbonyl compounds has been achieved by reactions of ammonium hydroxide and various amines with ketones and aldehydes. The process is based on the application of Raney type Ni-Al alloy in an aqueous medium. The reaction of the carbonyl compounds with the amine provided the corresponding Schiff bases that immediately underwent a reduction to provide primary and secondary amines as products. The controlled reaction of the Al content of the alloy with the solvent water generates hydrogen, and the in situ formed Raney Ni serves as a hydrogenation catalyst. The method is a simple and efficient way of preparing a broad variety of primary and secondary amines.
- Sch?fer, Christian,Ni?anci, Bilal,Bere, Matthew P.,Da?tan, Arif,T?r?k, Béla
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p. 3127 - 3133
(2016/09/09)
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- Grinding synthesis of schiff bases combined with infrared irradiation
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Solid-phase synthesis combined with infrared irradiation promoted the formation of a series of Schiff bases in the condensation reaction between substituted benzaldehydes and anilines, in the solvent free. Benzaldehydes and anilines, containing either electron withdrawing or electron-releasing groups, were evaluated their substituent effect on the formation of the Schiff bases. Moreover, this new procedure is environmentally benign because no solvent was employed in the transformations.
- Tong, Jian-Ying,Sun, Na-Bo,Wu, Hong-Ke
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p. 5399 - 5401
(2013/07/26)
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- Antioxidant activity of thio-schiff bases
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This study evaluated and compares the antioxidant activity of six resveratrol analogues. The analogues 4'- Hydroxyphenyl-benzo[d]thiazole (A), p-(N,N-dimethyl)aminobenzylidene-2-aminothiophenol (B) and p-Nitrobenzylidene- 2-aminothiophenol (C) were synthe
- Santos, Juliana Alves Dos,Lima, Rebeca Mol,Pereira, Thamiris Vilela,Carmo, Antonio Marcio Resende Do,Raposo, Nadia Rezende Barbosa,Silva, Adilson David Da
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p. 557 - 560
(2013/08/23)
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- Highly active and selective synthesis of imines from alcohols and amines or nitroarenes catalyzed by Pd/DNA in water with dehydrogenation
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A direct imination was developed from alcohols and amines under catalysis of Pd/DNA by dehydrogenation without additional oxidant, affording the corresponding imines in moderate to good yields with excellent chemoselectivity. By virtue of the liberated molecular hydrogen, the nitroarenes could also be deoxidized in situ into amines and a one-pot tandem synthesis of imines was achieved from nitroarenes. This heterogeneous catalyst can be recovered and reused at least five times by taking advantage of its water-soluble reversibility. All these conformations were performed smoothly in water under mild conditions, and an atom economical and environmentally benign synthesis was embodied in this imination.
- Tang, Lin,Sun, Huayin,Li, Yunfeng,Zha, Zhenggen,Wang, Zhiyong
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p. 3423 - 3428
(2013/01/16)
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- An expeditious one-pot synthesis of substituted phenylazetidin-2-ones in the presence of zeolite
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In this study, one-pot rapid and efficient series of phenylazetidin-2-ones were synthesized from N,N-dimethylaminobenzaldehyde, different substituted aromatic amines and phenylacetyl chloride in the presence of zeolite catalyst under microwave irradiation. We also reported schiff bases (1a-j) by classical and conventional microwave technique. The titled compounds are evaluated for their antimicrobial properties. The activities are due to Ci=O, Ci-N, linkages in 2-azetidinones. All the compounds have shown comparable antibacterial activities.
- Pagadala, Ramakanth,Meshram, Jyotsna S.,Chopde, Himani N.,Jetti, Venkateshwarlu,Udayini
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experimental part
p. 1067 - 1072
(2011/10/31)
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- Synthesis and photophysical properties of 2-Styrylquinazolin-4-ones
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Trans-2-Styryl-substituted 3H-, 3-phenyl-, and 3-naphthylquinazolin-4-ones and their 6,7-difl uoro derivatives were synthesized by condensation of appropriate 2-methylquinazolin-4-ones with aromatic aldehydes or by the transformation of the heterocycle of 2-methyl-3,1-benzoxazin-4-one under the action of benzylidenephenylamines. Pleiades Publishing, Ltd., 2011.
- Trashakhova,Nosova,Valova,Slepukhin,Lipunova,Charushin
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body text
p. 753 - 761
(2011/08/22)
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- Synthesis and medicinal properties of 4-benzylidene-1-phenyl-2-(substituted styryl)imidazolin-5-ones
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A series of 4-benzylidene-1-phenyl-2-(substituted styryl)imidazolin-5-ones have been synthesized by the interaction of 4-benzylidene-2-methyloxazol-5-one with different Schiff bases, prepared by simple condensation of aniline and various substituted benzaldehydes. The title compounds were evaluated for antiinflammatory activity in carrageenan foot paw edema model and in vitro antioxidant activity. Among the 14 compounds synthesized, dimethyl amino derivative and sterically hindered phenolic derivatives were found to possess good antiinflammatory activity which also exhibited antioxidant properties.
- Madhavi,Prasad,Bharathi
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experimental part
p. 5588 - 5594
(2012/08/07)
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- Graphite-supported gold nanoparticles as efficient catalyst for aerobic oxidation of benzylic amines to imines and N-substituted 1,2,3,4- tetrahydroisoquinolines to amides: Synthetic applications and mechanistic study
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Selective oxidation of amines using oxygen as terminal oxidant is an important area in green chemistry. In this work, we describe the use of graphite-supported gold nanoparticles (AuNPs/C) to catalyze aerobic oxidation of cyclic and acyclic benzylic amines to the corresponding imines with moderate-to-excellent substrate conversions (43-100%) and product yields (66-99%) (19 examples). Oxidation of N-substituted 1,2,3,4- tetrahydroisoquinolines in the presence of aqueous NaHCO3 solution gave the corresponding amides in good yields (83-93%) with high selectivity (up to amide/enamide=93:4) (6 examples). The same protocol can be applied to the synthesis of benzimidazoles from the reaction of o-phenylenediamines with benzaldehydes under aerobic conditions (8 examples). By simple centrifugation, AuNPs/C can be recovered and reused for ten consecutive runs for the oxidation of dibenzylamine to N-benzylidene(phenyl) methanamine without significant loss of catalytic activity and selectivity. This protocol "AuNPs/C+O 2" can be scaled to the gram scale, and 8.9 g (84% isolated yield) of 3,4-dihydroisoquinoline can be obtained from the oxidation of 10 g 1,2,3,4-tetrahydroisoquinoline in a onepot reaction. Based on the results of kinetic studies, radical traps experiment, and Hammett plot, a mechanism involving the hydrogen-transfer reaction from amine to metal and oxidation of M-H is proposed.
- So, Man-Ho,Liu, Yungen,Ho, Chi-Ming,Che, Chi-Ming
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experimental part
p. 1551 - 1561
(2010/06/20)
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- Kinetics and mechanism of the Pudovik reaction in the azomethine series: III. Acid-catalyzed hydrophosphorylation of imines
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A complex spectral (UV, IR, and 31P NMR), preparative, and kinetic investigation of the mechanism of the noncatalytic variant of the Pudovik reaction in the series of imines was carried out. The reaction proceeds through a four-center cyclic transition state. The transition state is highly labile, which determines its high sensitivity to the structure of the reagents, the nature of the solvent and catalyst, and some other factors. The necessary condition for the hydrophosphorylation of imines to occur is the participation of proton-donor reagents and acidic admixtures, specifically hydrolysis products of dialkyl hydrogen phosphites, such as monoalkyl dihydrogen phosphates and phosphorous acid, which act as acid catalysts. When the starting reagents are thoroughly purified and no such catalysts are present, the Pudovik reaction fails to occur in the imine series. Pleiades Publishing, Inc., 2006.
- Sobanov,Zolotukhin,Galkina,Galkin,Cherkasov
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p. 421 - 429
(2008/02/09)
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- Microwave-assisted synthesis of 4,4′-diaminotriphenylmethanes
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A fast, efficient and versatile route of synthesis of 4,4′- diaminotriphenylmethanes under microwave irradiation, suitable for parallel library syntheses were developed.
- Guzmán-Lucero,Guzmán,Likhatchev,Martínez-Palou
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p. 1119 - 1122
(2007/10/03)
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- Magnesium perchlorate as an efficient catalyst for the synthesis of imines and phenylhydrazones
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Magnesium perchlorate has been found to be an efficient catalyst for the synthesis of imines and phenylhydrazones by the reaction of carbonyl compounds with amines and phenylhydrazine in high yields at room temperatures and in short times. The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines affords the imines in excellent yields.
- Chakraborti, Asit K.,Bhagat, Srikant,Rudrawar, Santosh
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p. 7641 - 7644
(2007/10/03)
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- Clay catalyzed synthesis of imines and enamines under solvent-free conditions using microwave irradiation
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The reactions of primary and secondary amines with aldehydes and ketones, respectively, are accelerated by microwaves under solvent-free conditions in the presence of montmorillonite K 10 clay to afford a high yield synthesis of imines and enamines.
- Varma, Rajender S.,Dahiya, Rajender,Kumar, Sudhir
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p. 2039 - 2042
(2007/10/03)
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- Microwave-Assisted Facile Synthesis of Imines and Enamines using Envirocat EPZGR as a Catalyst
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In a simple microwave-assisted and environmentally benign approach, aldehydes and ketones react readily with primary and secondary amines to afford imines and enamines, respectively, under solvent-free conditions using Envirocat EPZGR as a catalyst.
- Varma, Rajender S.,Dahiya, Rajender
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p. 1245 - 1246
(2007/10/03)
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- Low-valent titanium mediated reductive deoxygenation of carbonyls to methylenes via carbon-nitrogen bond cleavage in N-(arylmethyl) anilines
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The reduction of aryl aldehydes and ketones in neutral medium, to the corresponding hydrocarbons via carbon-nitrogen bond cleavage of the intermediate N-(arylmethyl) anilines with low-valent titanium reagents is described. It provides a mild, convenient and selective pathway for deoxygenation of carbonyls without the production of any side product.
- Talukdar,Banerji
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p. 1051 - 1056
(2007/10/03)
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- SYNTHESIS OF SUBSTITUTED 5-CHLOROMETHYL-1,3-OXAZOLIDINES
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Substituted 5-chloromethyl-1,3-oxazolidines were synthesized from 1-chloro-2,3-epoxypropane and Schiff bases in carbon tetrachloride in the presence of stannic chloride at 5-10 deg C.It was shown by 1H NMR spectroscopy that 2,3-diaryl-5-chloromethyl-1,3-oxazolidines are formed as a single diastereomer while N-alkyl-substituted 5-chloromethyl-1,3-oxazolidines are formed as mixtures of two stereoisomers.
- Bulatova, O. F.,Romanov, N. A.,Chalova, O. B.,Rakhmankulov, D. L.
-
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- New Results in the Synthesis of Styrylazulene Derivatives: Application of the 'Anil Synthesis' to the Preparation of Azulenes Substituted with Styryl Groups at the Seven-Membered Ring
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The synthesis of 4,6,8-trimethyl-1-azulenes 5 (R=H, MeO, Cl) has been performed by Wittig reaction of 4,6,8-trimethylazulene-1-carbaldehyde (1) and the corresponding 4-(R-benzyl)(triphenyl)phosphonium chlorides 4 in the presence of EtONa/EtOH in boiling toluene (see Table 1).In the same way, guaiazulene-3-carbaldehyde (2) as well as dihydrolactaroviolin (3) yielded with 4a the corresponding styrylazulenes 6 and 7, respectively (see Table 1).It has been found that 1 and 4b yield, in competition to the Wittig reaction, alkylation products, namely 8 and 9, respectively (cf.Scheme 1).The reaction of 4,6,8-trimethylazulene (10) with 4b in toluene showed that azulenes can, indeed, be easily alkylated with the phosphonium salt 4b. 4,6,8-Trimethylazulene-2-carbaldehyde (12) has been synthesized from the corresponding carboxylate 15 by a reduction (LiAlH4) and dehydrogenation (MnO2) sequence (see Scheme 2).The Swern oxidation of the intermediate 2-(hydroxy-methyl)azulene 16 yielded only 1,3-dichloroazulene derivatives (cf.Scheme 2).The Wittig reaction of 12 with 4a and 4b in the presence of EtONa/EtOH in toluene yielded the expected 2-styryl derivatives 19a and 19b, respectively (see Scheme 3).Again, the yield of 19b was reduced by a competing alkylation reaction of 19b with 4b which led to the formation of the 1-benzylated product 20 (see Scheme 3).The 'anil synthesis' of guaiazulene (21) and the 4-R-benzanils 22 (R=H, MeO, Cl, Me2N) proceeded smoothyl under standard conditions (powered KOH in DMF) to yield the corresponding 4-azulene derivatives 23 (see Table 4).In minor amounts, bis(azulen-4-yl) compounds of type 24 and 25 were also formed (see Table 4).The 'anil reaction' of 21 and 4-NO2C6H4CH=NC6H5 (22e) in DMF yielded no corresponding styrylazulene derivative 23e.Insteed, (E)-1,2-bis(7-isopropyl-1-methylazulen-4-yl)ethene (27) was formed (see Scheme 4).The reaction of 4,6,8-trimethylazulene (10) and benzanil (22a) in the presence of KOH in DMF yielded the benzanil adducts 28 to 31 (cf.Scheme 5).Their direct base-catalyzed transformation into the corresponding styryl-substituted azulenes could not be realized (cf.Scheme 6).However, the transformation succeeded smoothly with KOH in boiling EtOH after N-methylation (cf.Scheme 6).
- Briquet, Anne Andree Sophie,Hansen, Hans-Juergen
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p. 1921 - 1939
(2007/10/02)
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- Mechanism of Thermal Z/E Isomerization of Substituted N-Benzylideneanilines. Nature of the Activated Complex with an sp-Hybridized Nitrogen Atom
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In order to study the mechanism of thermal geometrical isomerization involving a sp2-hybridized nitrogen atom, kinetic effects of substituent, solvent, and pressure were studied in substituted N-benzylideneanilines.The effect of the substituent on the aniline moiety was almost independent of the electronic nature of the benzylidene group, and the results could be described satisfactorily by log (k/k0) = ρ0 + r+(?+ - ?0) + r-(?- - ?0)>, except for the 4-(dimethylamino) group.The r- values were more than twice as large as r0, suggesting strongly that the aniline ring is in conjugation not with the carbon-nitrogen ? bond but with the nitrogen lone pair in the transition state.The lower activation enthalpies and fairly large negative activation entropies observed in N-(4-X-benzylidene)-4-nitroanilines also support this view.When a dimethylamino group exists in the 4-position of the aniline ring, the rate constants observed were larger than that expected from the above equation.This deviation suggests the existence of a reaction route where the two phenyl groups become coplanar in the transition state.Ab initio calculations on selected N-phenylformaldimines and N- benzylideneanilines were performed to characterize the actual relation between both reaction possibilities as alternative and parallel routes, respectively.On the basis of the experimental data, the rate constants for the two inversion isomerizations were estimated by assuming parallel reactions for three cases.
- Asano, Tsutomu,Furuta, Hiroyuki,Hofmann, Hans-Joerg,Cimiraglia, Renzo,Tsuno, Yuho,Fujio, Mizue
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p. 4418 - 4423
(2007/10/02)
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- Vibrational spectra and Raman excitation profiles of some Schiff bases
-
The pre-resonance Raman spectra of three Schiff-base have been recorded and analysed.The theoretical Raman intensity factors have been calculated using ALBRECHT and HUTLEY's theory for pre-resonance enhancement and are compared with those of experimentally observed values.The assignments of the fundamental modes of vibration in the range 1300-1700 cm-1 have also been attempted on the basis of i.r. and Raman data.
- Das, Radhendu,Kumar, Kamal
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p. 705 - 710
(2007/10/02)
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- Molecular Complexes of Benzylideneanilines With Some ?-Electron Acceptors
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Molecular complexes of some benzylideneanilines with tetracyanoethylene, 2,3-dichloro-5,6-dicyano-p-benzoquinone and chloranil have been studied spectrophotometrically.The formation constants (KCT) and extinction coefficients (εCT) o
- Hamed, M. M. A.,El-Gyar, S. A.,El-Nady, A.
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p. 728 - 731
(2007/10/02)
-