Isolation, synthesis and optimization of cyclopropanation process of 4-allyl-2-methoxyphenol

The synthesis of 4-((2,2-dichlorocyclopropyl)methyl)-2-methoxyphenol 2 have been accomplished by using cyclopropanation process and Reponse Surface Methodology [1,2]. This methodology was used to determine the optimal conditions for the cyclopropanation reaction of eugenol 1. The reaction time (X1) and the ratio of the reaction mixture’s solvent (X2) were the two investigated factors. The statistical analysis of this study indicates that both of these factors had significant effects on the cyclopropanation yield. The central composite design showed that polynomial regression models were in good agreement with the experimental results of the coefficient determination (0.95) of product 2 yield. The optimal conditions were 17.44 and 5.78 hours. In such condition, the predicted yield of the product 2 was 43.96%. Keywords: Eugenol; 4-((2,2-dichlorocyclopropyl)methyl)-2-methoxyphenol; Central composite design; Optimization experiment

Synthesis of pyrazolo-enaminones, bipyrazoles and pyrazolopyrimidines and evaluation of antioxidant and antimicrobial properties

A novel pyrazolo-enaminones, bipyrazoles and bipyrazolopyridines from 1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)butane-1,3-dione and 4-methyl-2-phenyl-2H-pyrazolo[3,4-b]pyridine-3,6(3aH,7H)-dione have been synthesized by assisted heating with microwave radiation without any catalyst. The pyridine and pyrazole ring formation has been developed from easily accessible enamino keto esters by formylation followed by intramolecular cyclization. The general applicability for the synthesis of the important pyrazolo-enaminones, bipyrazoles and pyrazolo-pyridines heterocycles was attributed to simplicity of operation, synthesis without catalyst, energy efficiency (shorter reaction time under microwave irradiation), good yields, more environmentally friendly and more cost-effective procedure. The antioxidant activity of new heterocyclic compounds was evaluated by free radical scavenging by DPPH assay. Several of these compounds showed good activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria

Siderophore-based detection of Fe(iii) and microbial pathogens

Siderophores are low-molecular-weight iron chelators that are produced and exported by bacteria, fungi and plants during periods of nutrient deprivation. The structures, biosynthetic logic, and coordination chemistry of these molecules have fascinated chemists for decades. Studies of such fundamental phenomena guide the use of siderophores and siderophore conjugates in a variety of medicinal applications that include iron-chelation therapies and drug delivery. Sensing applications constitute another important facet of siderophore-based technologies. The high affinities of siderophores for both ferric ions and siderophore receptors, proteins expressed on the cell surface that are required for ferric siderophore import, indicate that these small molecules may be employed for the selective capture of metal ions, proteins, and live bacteria. This minireview summaries progress in methods that utilize native bacterial and fungal siderophore scaffolds for the detection of Fe(III) or microbial pathogens.Massachusetts Institute of Technology. Dept. of Chemistr

CHARACTERIZATION AND VIBRATIONAL SPECTRA OF THE VITREOUS DOMAIN EXISTING IN THE TERNARY DIAGRAM Li2O-CdO-P2O5

L'analyse radiocristallographique a été réalisée sur des phosphates mixtes de Li et de Cd trempés à partir de l'état liquide. Cette technique a permis de délimiter un large domaine vitreux existant au sein du diagramme ternaire Li2O-CdO-P2O5. La stabilité thermique des verres ainsi isolés a été précisée après un recuit effectué pendant 14 heures sur plusieurs échantillons vitreux à différentes températures variant de 80 à 550°C. La spectroscopie Raman a été utilisée afin d'examiner l'évolution de la structure du verre au sein de son domaine d'existence.Xray analysis carried out on supercooled melts of mixed Li and Cd phosphates has permitted the determination of the border of a wide glass forming region inside the ternary system Li2O-CdO-P2O5. The heat stability of the isolated glasses has been determined using the annealing technique for 14 hours at different temperatures between 80 and 550°C for many compositions. Raman scattering was used to examine the evolution of glass structure inside the vitreous domain

Structural relationship between vitreous P2O5 and its relevant crystalline polymorphs by Raman spectroscopy

Vitreous and relevant crystalline polymorphs of P2O5 have been synthesised and characterised by X-ray diffraction and Raman scattering spectroscopy..