scholarly journals Radical Formation in Sugar-Derived Acetals under Solvent-Free Conditions

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5897
Author(s):  
Aleksandra A. Wróblewska ◽  
H. Y. Vincent Ching ◽  
Jurrie Noordijk ◽  
Stefaan M. A. De Wildeman ◽  
Katrien V. Bernaerts
Keyword(s):  
Hydrogen Abstraction ◽  
Solvent Free ◽  
Paramagnetic Resonance ◽  
Cyclic Acetals ◽  
Radical Degradation ◽  
Solvent Free Conditions ◽  
Amide Exchange ◽  
Methylene Unit ◽  
Electron Paramagnetic ◽  
Derivatives Of

The degradation of acetal derivatives of the diethylester of galactarate (GalX) was investigated by electron paramagnetic resonance (EPR) spectroscopy in the context of solvent-free, high-temperature reactions like polycondensations. It was demonstrated that less substituted cyclic acetals are prone to undergo radical degradation at higher temperatures as a result of hydrogen abstraction. The EPR observations were supported by the synthesis of GalX based polyamides via ester-amide exchange-type polycondensations in solvent-free conditions at high temperatures in the presence and in the absence of radical inhibitors. The radical degradation can be offset by the addition of a radical inhibitor. The radical is probably formed on the methylene unit between the oxygen atoms and subsequently undergoes a rearrangement.

Solvent-free synthesis of novel vanillidene derivatives of Meldrum's acid: biological evaluation, DNA and BSA binding study

RSC Advances ◽  
2016 ◽  
Vol 6 (45) ◽  
pp. 39452-39459 ◽  
Author(s):  
Nenad Janković ◽  
Jovana Muškinja ◽  
Zoran Ratković ◽  
Zorica Bugarčić ◽  
Branislav Ranković ◽  
...  
Keyword(s):  
Biological Evaluation ◽  
Solvent Free ◽  
Binding Study ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
Bsa Binding ◽  
Solvent Free Conditions ◽  
Derivatives Of ◽  
Solvent Free Synthesis

A series of novel O-alkyl vanillidene derivatives containing Meldrum's acid scaffold under solvent-free conditions were synthesized.

A mild and efficient chemoselective N-benzyloxycarbonylation of amines using TBAB as a catalyst under solvent-free conditions

2009 ◽  
Vol 87 (2) ◽  
pp. 393-396 ◽  
Author(s):  
Kothamasu Suresh Babu ◽  
Vidadala Rama Subba Rao ◽  
Ravu Ranga Rao ◽  
Sakhamuri Sivaram Babu ◽  
Janaswami Madhusudana Rao
Keyword(s):  
Efficient Method ◽  
Aromatic Amines ◽  
Solvent Free ◽  
Solvent Free Conditions ◽  
Derivatives Of

We describe a mild and efficient method for the chemoselective N-benzyloxycarbonylation of amines by treatment of amines and aminoesters with benzyloxycarbonyl chloride (Cbz-Cl) in the presence of TBAB under solvent-free conditions in excellent yields. The method is general for the preparation of a wide variety of N-Cbz derivatives of aliphatic, aromatic amines, and aminoesters.

scholarly journals Copper(II) Complexes of Organophoshonic Acids-A Comparative Study

2011 ◽  
Vol 8 (s1) ◽  
pp. S271-S281
Author(s):  
B. Venkateswara Rao ◽  
D. M. Puri
Keyword(s):  
Phosphonic Acid ◽  
Octahedral Geometry ◽  
Spectral Studies ◽  
Diphosphonic Acid ◽  
Paramagnetic Resonance ◽  
Diethylene Triamine ◽  
Coordination Sites ◽  
Infrared Spectral ◽  
Electron Paramagnetic ◽  
Derivatives Of

Polynuclear copper(II) derivatives of 1-hydroxyethylidenediphosphonic acid (HEDP), 1-aminoethylidenediphosphonic acid (AEDP, H4L),α-aminobenzylidene diphosphonic acid (ABDP, H4L), 1-amino-2-carboxyethane- 1,1-diphosphonic acid (ACEDP, H5L), 1,3 diaminopropane-1,1,3,3-tetra-phosphonic acid (DAPTP, H8L), Ethylenediamine-N,N'-bis (dimethyl-methylenephosphonic) acid (EDBDMPO, H4L),o-phenylene-diamine-N,N'-bis (dimethylmethylenephosphonic) acid (PDBDMPO, H4L), diethylene triamine –N,N,N',N',N"N-penta (methylene phosphonic) acid (DETAPMPO, H10L) and diethylene triamine –N,N"-bis (dimethyl methylene phosphonic) acid (DETBDMPO, H4L) have been prepared in aqueous medium. The general formula of derivatives from elemental analysis was found to be Cu2L.XH2O (in case of AEDP, ABDP, EDBDMPO, PDBDMPO, DETBDMPO), Cu5L2.XH2O (in case of ACEDP) Cu4L.XH2O, Cu2H4L. XH2O (in case of DAPTP) and Cu5L.XH2O (in case of DETAPMPO). The electronic spectra have shown them to be six coordinated with slight distortion from octahedral geometry. Antiferromagnetism was inferred from magnetic moment data. Infrared spectral studies were carried out to determine coordination sites. EPR (Electron Paramagnetic Resonance) spectra that supports the presence of tetragonal distortion and antiferromagnetic behaviour, have also been studied.

EFFECTS OF COPPER DOPING ON DIELECTRIC AND A.C. CONDUCTIVITY IN LAYERED SODIUM TRI-TITANATE CERAMIC

2013 ◽  
Vol 27 (22) ◽  
pp. 1350114 ◽  
Author(s):  
SHRIPAL ◽  
SHAILJA DWIVEDI ◽  
RAKESH SINGH ◽  
R. P. TANDON
Keyword(s):  
Ionic Conduction ◽  
Relaxation Times ◽  
Paramagnetic Resonance ◽  
Temperature Range ◽  
Higher Temperature ◽  
Polaron Conduction ◽  
Tan Δ ◽  
Lower Temperature ◽  
Electron Paramagnetic ◽  
Derivatives Of

Electron paramagnetic resonance (EPR) spectra of 0.01, 0.1 and 1.0 molar percentage (mp) of CuO doped derivatives of layered Na 2 Ti 3 O 7 ceramic have been reported. The results show that copper substitutes as Cu 2+ at Ti 4+ octahedral sites. From the dependence of loss tangent ( tan δ) and the relative permittivity (ε′) on temperature and frequency, it is concluded that all the derivatives are of polar nature. The relaxation peaks at lower temperatures have been attributed to the presence of different types of dipoles, whereas peaks in the higher temperature region indicate possible ferroelectric phase transition. The dependence of conductivity on temperature show that electron hopping (polaron) conduction exists in a wide span of temperature range. However, the associated interlayer ionic conduction exists in a small temperature range. Interlayer alkali ion hopping mechanism of conduction has been proposed toward higher temperatures. The conductivity versus frequency plots reveal that the polaron conduction plays a prominent role toward the lower temperature side that diminishes with the rise in temperature. The most probable relaxation times for 0.01 and 0.1 mp CuO doped derivatives are almost same but it records an increased value for 1.0 mp doped material. This again attributes to the possible change in the symmetry of copper environment.

NiFe2O4@SiO2 @amino Glucose Magnetic Nanoparticle under Solvent-free Condition: A New, mild, Simple and Effective Avenue for the Synthesis of Quinazolinone, Imidazo[1,2-a]Pyrimidinone and Novel Derivatives of Amides

2020 ◽  
Vol 17 (4) ◽  
pp. 304-312
Author(s):  
Leila Z. Fekri
Keyword(s):  
Reaction Times ◽  
Solvent Free ◽  
Environmentally Benign ◽  
Multicomponent Synthesis ◽  
Solvent Free Condition ◽  
Amide Derivatives ◽  
Solvent Free Conditions ◽  
Ft Ir ◽  
First Time ◽  
Derivatives Of

Background: Imidazo[1,2-a]pyrimidinone, quinazolinone and amide derivatives have attracted a lot of interest because of their broad scope of biological and pharmacological activities. There are a lot of methods reported in the literature for their synthesis. Therefore, we became interested in developing a convenient synthetic method for the preparation of imidazoquinazolinone and amide derivatives. Objective: NiFe2O4@SiO2 @glucose amine were synthesized, characterized and have been used for the green, effective and mild multicomponent synthesis of quinazolinones, benzoimidazo[1,2-a]pyrimidinones and amides under solvent-free conditions in short reaction times and excellent yields. To expand of the scope of this avenue, multicomponent synthesis of mono and bis novel amides was tested for the first time. All of the products were characterized by mp, FT-IR, NMR and elemental analysis. Methods: Aldehyde (1mmol), 2-amino benzimidazole (1 mmol), dimedone (1mmol) or indane-1,3-dione (1 mmol) for the synthesis of quinazoline or imidazopyrimidinones and arene (1mmol), anhydride (1mmol), 2- aminobenzimidazole (1mmol) for the synthesis of amides in the nanocatalyst NiFe2O4@SiO2@glucose amine (0.15mol%: 0.05g) were stirred by a magnet for the required reaction time. After completion of the reaction, as indicated by TLC, the products were collected and recrystallized from ethanol if necessary. Results: We present a novel avenue for the synthesis of benzimidazo[1,2-a] pyrimidinones, quinazolinones and amides in the presence of NiFe2O4@SiO2@glucose amine under solvent-free conditions. Conclusion: In conclusion, we developed NiFe2O4@SiO2 @glucose amine-catalysed multicomponent synthesis of quinazolinones and imidazo[1,2-a]pyrimidinones using the reaction of benzaldehyde, dimedone or indane-dione and 2-aminobenzimidazole and multicomponent synthesis of amides using arenes, cyclic anhydrides and 2-aminobenzimidazole by a solvent-free technique. This method proves to be a robust and innovative approach for the synthesis of a biologically important structure. The operational simplicity, the excellent yields of products, ease of separation and recyclability of the magnetic catalyst, waste reduction and high selectivity are the main advantages of this method. Furthermore, this new avenue is cheap and environmentally benign.

Sign in / Sign up

Export Citation Format

Share Document