Selectivities in the Microwave-Assisted Organic Reactions

Xu, Jiaxi

doi:10.1201/9781351240499-6

Cited by 3 publications

(6 citation statements)

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“…The glass-reactor wall is not directly heated; instead of that, direct "in-core" heating is promoted, leading to homogeneous heating, which increases the reaction rate in comparison with the conventional synthesis methods. 24 Silylation reaction (covalent grafting of SCAs onto a surface) has been typically performedin most of the cited literaturein aqueous solutions by a sequential hydrolysis/ condensation reaction. Nonetheless, it is a nonhomogeneous process and poorly reproducible because it produces an islandtype grafting because of condensation and clustering of the SCAs.…”

Section: ■ Introductionmentioning

confidence: 99%

“…On the other hand, microwave-assisted synthesis is a powerful and promising technique to synthesize molecules using dedicated microwave reactors. The glass-reactor wall is not directly heated; instead of that, direct “in-core” heating is promoted, leading to homogeneous heating, which increases the reaction rate in comparison with the conventional synthesis methods . Silylation reaction (covalent grafting of SCAs onto a surface) has been typically performedin most of the cited literaturein aqueous solutions by a sequential hydrolysis/condensation reaction.…”

Section: Introductionmentioning

confidence: 99%

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Super-Anticorrosive Materials Based on Bifunctionalized Reduced Graphene Oxide

Ramírez-Soria

León-Silva

Rejón-García

et al. 2020

ACS Appl. Mater. Interfaces

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The design of new materials with two or more functional groups must be strongly considered to achieve multifunctional coatings with outstanding properties such as active−passive protection against corrosion, low-friction, antifouling, and sensing, among others. In this sense, nanocomposites based on solvent-free epoxy resin/bifunctionalized reduced graphene oxide layers with NH 2 and NH 3 + groups (ER/BFRGO) with super-anticorrosive properties are for the first time reported here. The amine groups (−NH 2 ) act as cross-linker agents, which react with epoxy terminal groups from resin, thus closing the gap between the BFRGO layers and the polymeric matrix. Meanwhile, the ammonium ions (−NH 3 + ) are effective trapping agents of negatively charged atoms or molecules (e.g., Cl − ). This novel combination enables us to obtain nanocomposite coatings with passive−active protection against corrosion. ER/BFRGO deposited onto A36 mild steel exhibited a remarkably enhanced barrier against corrosion into a saline medium (1 M NaCl; 58.4 g/L), wherein the corrosion current density (i corr ) was diminished 6 orders of magnitude (i corr = 5.12 × 10 −12 A/ cm 2 ), with respect to A36 mild steel coated only with ER (i corr = 2.34 × 10 −6 A/cm 2 ). Also, the highest polarization resistance R p = 6.04 × 10 7 Ω/cm 2 was obtained, which represents the lowest corrosion rate and corresponds to 3 orders of magnitude higher than A36 mild steel coated with ER (R p = 1.43 × 10 4 Ω/cm 2 ). The strategy of bifunctionalization proposed herein to obtain bifunctionalized reduced GO with NH 2 and NH 3 + groups has not been disclosed in the literature before; in consequence, this work opens a new pathway toward the design of smart materials based on multifunctional nanomaterials.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Super-Anticorrosive Materials Based on Bifunctionalized Reduced Graphene Oxide

Ramírez-Soria

León-Silva

Rejón-García

et al. 2020

ACS Appl. Mater. Interfaces

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“…Based on our previous results [ 30 ], we presume that the MW heating approach is more effective in [3 + 2] dipolar cycloaddition reactions due to two factors: the mode of action under MW irradiation and the structure of the ylide intermediate. The MW theory [ 24 , 30 , 31 ] states that the dielectric heating effect of MW depends essentially on the dipole moment of the molecules: the greater the dipole moment is, the larger the effect of the MW energy will be. The ylides are excellent dipoles (they have a 1,2-dipolar structure) and, therefore, the efficiency of MW heating increases considerably when compared with TH.…”

Section: Resultsmentioning

confidence: 99%

“…In recent years, microwave- and ultrasound-assisted reactions have proved to be a new trend in synthetic organic chemistry [ 22 , 23 , 24 , 25 , 26 ], offering a facile and useful alternative in a large variety of syntheses [ 2 , 22 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. In comparison with conventional thermal heating (TH), both microwave and ultrasound irradiation have several important advantages: improved yields, high purity of the compounds, increased selectivity, decreases of reaction time, lower costs and simplicity in handling and processing.…”

Section: Introductionmentioning

confidence: 99%

Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes

et al. 2020

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We present herein a straightforward and efficient pathway for the synthesis of pyrrolophthalazine cycloadducts via Huisgen [3 + 2] dipolar cycloaddition reactions of phthalazinium ylides to methyl propiolate or dimethyl acetylenedicarboxylate (DMAD). A thoroughly comparative study concerning the efficiency of synthesis, conventional thermal heating (TH) versus microwave (MW) and ultrasound (US) irradiation, has been performed. The cycloaddition reactions of phthalazinium ylides to methyl propiolate occur regiospecific, with a single regioisomer being obtained. Under conventional TH, the cycloaddition reaction of phthalazinium ylides with DMAD occurs to a mixture of inseparable partial and fully aromatized pyrrolophthalazine cycloadducts, while MW or US irradiation are leading only to fully aromatized compounds, with the reactions becoming selective. A feasible mechanism for formation of fully aromatized compounds is presented. Besides selectivity, it has to be noticed that the reaction setup under MW or US irradiation offer a number of other certain advantages: higher yields, decreasing of the amount of used solvent comparative with TH, decreasing of the reaction time from hours to minutes and decreasing of the consumed energy; consequently, these reactions could be considered environmentally friendly.

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“…Recent years have seen a rise in the use of microwave and ultrasonic-assisted reactions in synthetic organic chemistry [ 27 , 28 , 29 , 30 ], providing a quick and practical alternative in a wide range of syntheses [ 31 , 32 , 33 , 34 , 35 , 36 ]. Both microwave and ultrasound irradiation provide several significant advantages over traditional thermal heating (TH), including greater yields, high purity of the compounds, increased selectivity, decreased reaction times, cheaper costs, and improved ease of handling and processing.…”

Section: Introductionmentioning

confidence: 99%

The Effective Synthesis of New Benzoquinoline Derivatives as Small Molecules with Anticancer Activity

Zbancioc,

Mangalagiu,

Moldoveanu

2023

Pharmaceuticals

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In this study, some novel benzo[c]quinoline derivatives were synthesized, their structural characteristics were described, and their in vitro anticancer efficacy was investigated. The synthesis involves an initial quaternization of the nitrogen atom from benzo[c]quinoline and then a [3+2] dipolar cycloaddition reaction of the in situ formed ylide. The effectiveness of synthesis using traditional thermal heating (TH) compared to microwave (MW) and ultrasound (US) irradiation was investigated in detail. The setup of a reaction under MW or US irradiation offers a number of additional benefits: higher yields, a reduction in the amount of solvent used compared to TH, a reduction in the reaction time from hours to minutes, and a reduction in the amount of energy consumed. The structure of all the obtained compounds was proved by several spectral techniques (FTIR, HRMS, and NMR). All benzo[c]quinoline derivatives (quaternary salts and cycloadducts) along with ten other benzo[f]quinoline derivatives (quaternary salts and cycloadducts), previously obtained, were tested in an in vitro single-dose anticancer experiment. The results demonstrated that the cycloadducts 5a–c and 6a–c exhibit stronger anticancer activity than quaternary salts 3a–c. The most active compound is compound 5a, with anticancer activity on most of the cell lines studied, while the second most active compound is 6c, showing significant lethality for the SR leukemia cell line (17%). Structure-activity relationship (SAR) correlations are also included in the study.

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Selectivities in the Microwave-Assisted Organic Reactions

Cited by 3 publications

References 1 publication

Super-Anticorrosive Materials Based on Bifunctionalized Reduced Graphene Oxide

Super-Anticorrosive Materials Based on Bifunctionalized Reduced Graphene Oxide

Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes

The Effective Synthesis of New Benzoquinoline Derivatives as Small Molecules with Anticancer Activity

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