Fluorinated ionic surfactant microemulsions in hydrofluorocarbon 134a (HFC 134a)

The factors influencing the formation of water-in-134a-propellant microemulsions using the fluorinated ionic surfactants ammonium perfluorooctanoate, ammonium perfluoroheptanoate, and sodium perfluorooctanoate has been determined. None of the fluorinated ionic surfactants could be used to prepare clear, one-phase systems when used as sole surfactant, but they could be when combined with a short-chain fluoro- or hydrocarbon alcohol in surfactant:cosurfactant weight-mixing ratios (K(m)) in the range 1:2 to 2:1. When hydrocarbon alcohols were used this clear region extended over a wide range of compositions and was confirmed by means of photon correlation spectroscopy (PCS) to contain microemulsion droplets in the propellant-rich part of the phase diagram. PCS studies performed in the presence of the water-soluble drug terbutaline sulfate showed that it was possible to solubilize the drug within water-in-propellant microemulsion droplets. These studies confirm for the first time that it is possible to prepare water-in-propellant 134a microemulsions using fluorinated ionic surfactants and to solubilize water-soluble drugs within these systems.     

UTLC: An Advanced Technique in Planar Chromatography

As part of increasing research in the field of separation science, there have been many efforts to undertake planar chromatography with more efficient separation and better resolution in the shortest period of time, together with a specificity and a capability to identify more precisely an unknown compound present in a mixture. Ultra-thin layer chromatography (UTLC) is a modern technique which gives separation within 10–30 mm and development in just 1–6 min, with the consumption of less solvent. The stationary phase of UTLC is made up of a silica gel monolithic layer of 10 μm thickness having 3- to 4-nm mesopores and 1- to 2-μm macropores. Glancing angle deposition (GLAD)-UTLC is a modification of UTLC which gives separation within 15 mm distance and in less than 2 min. Anisotropic media of GLAD UTLC gives a unique migration direction effect. UTLC atmospheric pressure–matrix-assisted laser desorption ionizer–mass spectrometery (UTLC-AP-MALDI-MS) is a choice of technique for the identification of an unknown compound in a mixture or an impure form. ULTC-AP-MALDI-MS allows the fast changing of plates, produces more intact protonated molecules, less fragmentation and less entry of chromatographic material, and yielding less complicated spectra than the vacuum condition. Thus, UTLC is a useful technique for very rapidly giving the separation and identification of new components present in mixtures. This review provides a brief overview of UTLC, the stationary phases used for UTLC, and the detection options and applications of UTLC.     

Synthesis and characterization of polylactic acid (PLA) using a solid acid catalyst system in the polycondensation method

In this study, synthesis of poly(l(+) lactic acid) was carried out by using an acid catalyst. Neat chlorosulfonic acid reacts with cellulose to give cellulose sulfuric acid in which sulfuric acid is immobilized on the cellulose surface via bond formation. Cellulose sulfuric acid was used as a catalyst in a quantity of 1.0 wt.% calculated on the monomer. Polycondensation was carried out over a period of 24 h. The resulting poly(l(+) lactic acid) was characterized by Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) thermogravimetric analysis (TGA), ¹H and ¹³C nuclear magnetic resonance (NMR), and gel permeation chromatography. The molecular weight of poly(l-lactic acid) reached as high as 14,875.     

Palladium catalyzed domino C-H activation strategy: An access to 9- fluorenones

Palladium catalyzed domino C-H functionalization reaction of arylaldehyde with dihaloarene has been developed to access 9-flourenone molecules. Bidentate ligand assisted strategy, single step reaction, high yield and excellent functional group tolerance make this method concise and effective for the synthesis of 9-flourenone. In addition, proposed method has been successfully employed to synthesise Tilorone in gram scale.     

Synthesis,In Vitro Biological Screening,and In Silico Computational Studies of Some Novel Imidazole‐2‐thiol Derivatives

Substituted imidazole analogues 2‐((5‐acetyl‐4‐methyl‐1‐phenyl‐1H‐imidazole‐2‐yl)thio)‐N‐phenylacetamides ( 3a – 3m ) have been synthesized from 1‐[1‐(phenyl)‐2‐mercapto‐4‐methyl‐1H‐imidazol‐5‐yl]‐ethanone ( 1a – 1e ) and 2‐chloro‐N‐phenylacetamide ( 2a – 2i ) in the presence of potassium carbonate as a catalyst in dimethylformamide under microwave irradiation as well as conventional method. Structures of the obtained compounds have been confirmed by advance spectroscopic techniques such as IR, ¹H NMR, ¹³C NMR, and mass spectrometry. All the synthesized compounds were tested for their in vitro antimicrobial and antituberculosis activities. Good antibacterial molecules were further screened for the bacterial resisted cell line, from which compound 3b shows maximum inhibition. In silico molecular docking study was carried out to discover the binding affinity of synthesized compounds with active site of transferase (PDB ID: 1HNJ) and antibiotic resistance (PDB ID: 1W3R) protein. Moreover, molecular dynamics study of the 3b ‐1W3R complex has also been performed, as 3b has a good antibacterial activity as compared with other.     

Preparation and physicochemical characterization of carbamazepine (CBMZ): para-sulfonated calix[n]arene inclusion complexes

The formation of inclusion complexes with para-sulfonated calix[n]arene (PSC[n]A) was studied for carbamazepine (CBMZ), a poorly water soluble anticonvulsant drug. The effect of PSC[4]A and PSC[6]A on aqueous solubility of carbamazepine was studied extensively. The complete complexation of the drug was achieved after 48 h of shaking with PSC[n]A in water and evaporation of water to get solid complex. The interaction between PSC[n]A and CBMZ in solid state inclusion complexes was accomplished by aqueous phase solubility studies, HPLC, DSC, PXRD, FTIR, UV–Vis, and FT-Raman spectroscopy. The solubility of CBMZ increases as a function of PSC[n]A concentration. The results of the two phase solubility experiments are in good conformity to signify the formation of 1:1 (PSC[6]A:CBMZ) and 2:1 PSC[4]A:CBMZ complexes. The order of dissolution rate of CBMZ is inclusion complex > physical mixture > drug alone. The purpose of this study was to enhance solubility resulting in high dissolution rate and bioavailability of this essentially water insoluble drug.     

Liquid crystals based on calix[4]arene Schiff bases

New liquid crystals based on calix[4]arene Schiff base were prepared by the reaction of tetraamino-calix[4]arene with aldehydes (4-hydroxy benzaldehyde, 2-vanillin, 4-vanillin and 2-hydroxy naphthaldehyde). Dielectric investigations on a magnetically oriented sample forming N, SmA, and SmC phases were carried out. The dielectric constant (ε’ and ε”) and dielectric loss (tan δ) have been determined as a function of frequency (20 Hz–2 MHz). The synthesized derivatives were purified and characterized by FT-IR, ¹H-NMR, ¹³C-NMR and MALDI-TOF MS. All the synthesized compounds were investigated for liquid crystalline properties using DSC (Differential Scanning Calorimetry), DTA (Differential Thermal Analysis) and POM (Polarizing Optical Microscopy) attached with a hot stage. They generally exhibited nematic and typical fanlike or mosaic texture, which suggest the ordered smectic mesophases. Compounds were found to adopt a specific molecular structure due to the rigid bowl like calix[4]arene core, i.e., a cone-like structure with mesogenic units aligned within the molecule.     

Host-guest interactions template: the synthesis of a [3]catenane

Formation of a [3]catenane containing dibenzo-24-crown ether wheels and a large dipyridiniumethane ring is templated by formation of a host-guest adduct between the [3]catenane and the external crown ether.