Recent advances in the chemistry of imine-based multicomponent reactions (MCRs)

Choudhury, Lokman H.; Parvin, Tasneem

doi:10.1016/j.tet.2011.07.020

Cited by 157 publications

(56 citation statements)

References 81 publications

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“…38 By far the most common way to make imines, whether stable species or transient reaction intermediates, is by the condensation of aldehydes or ketones with amines. 39 The ability to made imines by a sulfonyl radical elimination, especially when coupled with a prior radical reaction (here, the cyclizations), provides a powerful alternative to the usual condensation route that differs both in the bonds that are formed and in the reaction conditions.…”

Section: Discussionmentioning

confidence: 99%

Radical Cyclizations of Cyclic Ene Sulfonamides Occur with β-Elimination of Sulfonyl Radicals to Form Polycyclic Imines

et al. 2013

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Radical cyclizations of cyclic ene sulfonamides provide stable bicyclic and tricyclic aldimines and ketimines in good yields. Depending on the structure of the precursor, the cyclizations occur to provide fused and spirocyclic imines with five-, six-, and seven-membered rings. The initial radical cyclization produces an α-sulfonamidoyl radical that undergoes elimination to form the imine and a phenylsulfonyl radical. In a related method, 3,4-dihydroquinolines can also be produced by radical translocation reactions of N-(2-iodophenylsulfonyl)tetrahydroisoquinolines. In either case, very stable sulfonamides are cleaved to form imines (rather than amines) under mild reductive conditions.

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Section: Discussionmentioning

confidence: 99%

Radical Cyclizations of Cyclic Ene Sulfonamides Occur with β-Elimination of Sulfonyl Radicals to Form Polycyclic Imines

et al. 2013

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“…Imine contains electron-rich nitrogen atoms which acts as a typical nucleophile. In addition, the imine has also an electrophilic nature due to the carbon atom in C=N group [26][27][28]. The chemical properties of imines are often compared to the carbonyl compounds.…”

Section: Effect Of Water Contentmentioning

confidence: 99%

“…The possible reactions of imines, described in the literature [26][27][28], are reversible exchange and metathesis. Such reactions can occur in heated samples; hence, the various chitosan derivatives can appear in the degradation products.…”

Section: Effect Of Water Contentmentioning

confidence: 99%

“…Another type of imine reaction is cycloaddition with alkenes or dienes, which have been explored by few research groups [26][27][28]. Although unsaturated and aromatic degradation products are formed in thermally degraded chitosan (mainly in the absence of oxygen), the above-mentioned reaction is unlikely because it requires Lewis acid or special catalyst to activate the imine.…”

Section: Effect Of Water Contentmentioning

confidence: 99%

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Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Ziegler-Borowska

Chełminiak

Kaczmarek

et al. 2016

J Therm Anal Calorim

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Three different novel chitosan derivatives for medical or biotechnological applications have been successfully obtained by chemical modification of reactive amino and hydroxyl groups in chitosan chain. The modification has led to incorporation of different amount (one to three) of long-distanced amino and imine groups into each repeating unit. These highly functionalized chitosan derivatives were used as a matrix for magnetite nanoparticles. The thermal stability of all obtained chitosan materials has been determined using thermogravimetric analysis in oxidative and inert atmosphere. Chitosan containing two side substituents behaves differently from the other two, which is caused by the significant water uptake. Magnetite causes decrease in thermal stability of studied chitosan derivatives. The highest stability is observed for the nanocomposite obtained from chitosan with three side groups. The changes in the structure of the magnetite core have been observed above 600°C in nitrogen. Due to the different competitive reactions occurring in the modified chitosan, the proposed mechanism of thermal degradation is very complex.Keywords Modified chitosan Á Side group effect Á Thermogravimetric analysis Á Effect of water residue Á Thermal degradation mechanism

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“…Several MCRs are found in the literature using the most varied types of reagents. To construct nitrogencontaining molecules, the imine-based MCRs are the most explored type in recent years [4]. Usually, imines are electrophiles in MCRs.…”

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confidence: 99%

First synthesis of aminonaphthoquinones derived from lawsone in a colloidal dispersion system created by a Brønsted acid-surfactant-combined catalyst in water: An environmentally friendly protocol

Filho¹,

Fiorot²,

Lacerda³

et al. 2015

Colloids and Interface Science Communications

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Recent advances in the chemistry of imine-based multicomponent reactions (MCRs)

Cited by 157 publications

References 81 publications

Radical Cyclizations of Cyclic Ene Sulfonamides Occur with β-Elimination of Sulfonyl Radicals to Form Polycyclic Imines

Radical Cyclizations of Cyclic Ene Sulfonamides Occur with β-Elimination of Sulfonyl Radicals to Form Polycyclic Imines

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

First synthesis of aminonaphthoquinones derived from lawsone in a colloidal dispersion system created by a Brønsted acid-surfactant-combined catalyst in water: An environmentally friendly protocol

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