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.     

β-Isothiocyanatoketones: A Convenient Source of Heterocyclic Compounds

Summary. The preparation of -isothiocyanatoketones and their reactions leading to formation of pyrimidine and bicyclic, tricyclic, tetracyclic, and pentacyclic heterocyclic compounds are reviewed. A few references concerning the rearrangement of heterocyclic compounds are also included. Some of the compounds reported have shown good antiinflammatory activity.     

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.     

Chemoselective thioacetalisation and transthioacetalisation of carbonyl compounds catalysed by tetrabutylammonium tribromide (TBATB)

Thioacetals and thioketals of various aldehydes and ketones were obtained directly from carbonyl compounds or by a transthioacetalisation process from cyclic O,O-acetals in the presence of dithiols and a catalytic amount of tetrabutylammonium tribromide (TBATB). Chemoselective thioacetalisation of aromatic aldehydes containing an electron-donating group in the presence of an aldehyde containing an electron-withdrawing group, aldehydes in the presence of ketones, aliphatic cyclic ketones in the presence of aromatic ketones and less hindered ketones in the presence of more hindered ketones have been achieved. A cyclic acetal containing an electron-donating group has been chemoselectively transthioacetalised in the presence of an acetal having an electron-withdrawing substituent. These selectivities are due to the intrinsic reactivity of the substrate themselves and are independent of the catalyst and reaction conditions. Shorter reaction times, mild reaction conditions, stability of acid sensitive protecting groups, high efficiencies, facile isolation of the desired products and the catalytic nature of the reagent are the attractive features of the present method.     

BSE control: detection of gelatine-derived peptides in animal feed by mass spectrometry

The epidemic of bovine spongiform encephalopathy (BSE) is thought to have resulted from feeding scrapie-infected sheep to cattle. This has led to a ban of feeding animals with "processed animal protein"(PAP). We report a novel approach for the mass spectrometric detection of PAP contamination in animal feedstuffs by detecting gelatine, a derivative of the major animal protein collagen. A method was developed to hydrolyse gelatine standards with hydrochloric acid, followed by detection of the derived hydrolytic peptides at m/z 828, 915, 957 and 1044 by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography electrospray ionisation mass spectrometry (LC-ESI-MS-MS). The marker peptides can be detected at concentrations of 100 ng ml(-1) gelatine in water with MALDI. The procedure was adapted to obtain a suitable peptide map of gelatine extracted from spiked feed. The ratio of signal area of the gelatine-derived peptide at m/z 1044 to the internal standard at m/z 556 is shown to relate to the total amount of gelatine present in the sample.