Nucleophilic Displacement Reaction on Tosyl Cellulose by L-Methionine to the Synthesis of Novel Water-Soluble Cellulose Derivative and Its Antibacterial Activity

A novel ampholytic cellulose derivative, cellulose-L-methionine, has been synthesized by means of an esterification reaction of microcrystalline cellulose with tosyl chloride (p-TsCl) in DMAc/LiCl (8%) at 8°C that was followed by nucleophilic displacement (SN) of the tosyl group by the L-methionine amino acid. The resulting structure of cellulose-L-methionine has been characterized by elemental analysis (CHNSO), Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and scanning electron microscopy (SEM). The antibacterial activity of the synthesized product was screened against Gram-positive and Gram-negative microbial strains such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, by the agar well diffusion method, and compared with commercial antibiotics such as ampicillin and chloramphenicol. It was found that antibacterial experiment revealed excellent antibacterial activity of the cellulose-methionine with respect to a minimal inhibitory concentration (MIC) reference.

Catalytic, Regioselective Sulfonylation of Carbohydrates with Dibutyltin Oxide under Solvent-Free Conditions

A simple approach was developed for the solvent-free regioselective functionalization of carbohydrate polyols with 4-toluesulfonyl (tosyl) group, allowing the easy and quick activation of a saccharide site with a tosylate leaving group. The method is based on the use of catalytic dibutyltin oxide and tetrabuylammonium bromide (TBAB), and a moderate excess of N,N-diisopropylethyl amine (DIPEA) and tosyl chloride (TsCl), leading to the selective functionalization at 75 °C of a secondary equatorial hydroxy function flanked by an axial one in a pyranoside. The procedure is endowed with several advantages, such as the use of cheap reagents, experimental simplicity, and the need for reduced reaction times in comparison with other known approaches.

Full-Colour Solvatochromic Fluorescence Emitted from a Semi-Aromatic Imide Compound Based on ESIPT and Anion Formation

A multi-colour solvatochromic fluorophore was developed by substituting a fully organic 3-amino-N-cyclohexyl phthalimide group with a p-toluenesulfonyl (tosyl) group. This compound is essentially colourless in the visible region and exhibits...

Improved Oxidative C-C Bond Formation Reactivity of High-Valent Pd Complexes Supported by a Pseudo-Tridentate Ligand

<p>There is a large interest in developing oxidative transformations catalyzed by palladium complexes that employ environmentally friendly and economical oxidizing reagents such as dioxygen. Recently, we have reported the isolation and characterization of various mononuclear Pd^III and Pd^IV complexes supported by the tetradentate ligands <i>N,N’</i>-di-alkyl-butyl-2,11-diaza[3.3](2,6)pyridinophane (^RN4, R = ^tBu, ⁱPr, Me), and the aerobically-induced C-C and C-heteroatom bond formation reactivity was investigated in detail. Given that the steric and electronic properties of the multidentate ligands were shown to tune the stability and reactivity of the corresponding high-valent Pd complexes, herein we report the use of an asymmetric N4 ligand, <i>N-</i>mehtyl-<i>N’</i>-tosyl-2,11-diaza[3.3](2,6)pyridinophane (^TsMeN4), in which one amine N atom contains a tosyl group. The N-Ts donor atom exhibits a markedly reduced donating ability, which led to the formation of transiently stable Pd^III and Pd^IV complexes, and consequently the corresponding O₂ oxidation reactivity and the subsequent C-C bond formation was improved significantly.</p>

Improved Oxidative C-C Bond Formation Reactivity of High-Valent Pd Complexes Supported by a Pseudo-Tridentate Ligand

<p>There is a large interest in developing oxidative transformations catalyzed by palladium complexes that employ environmentally friendly and economical oxidizing reagents such as dioxygen. Recently, we have reported the isolation and characterization of various mononuclear Pd^III and Pd^IV complexes supported by the tetradentate ligands <i>N,N’</i>-di-alkyl-butyl-2,11-diaza[3.3](2,6)pyridinophane (^RN4, R = ^tBu, ⁱPr, Me), and the aerobically-induced C-C and C-heteroatom bond formation reactivity was investigated in detail. Given that the steric and electronic properties of the multidentate ligands were shown to tune the stability and reactivity of the corresponding high-valent Pd complexes, herein we report the use of an asymmetric N4 ligand, <i>N-</i>mehtyl-<i>N’</i>-tosyl-2,11-diaza[3.3](2,6)pyridinophane (^TsMeN4), in which one amine N atom contains a tosyl group. The N-Ts donor atom exhibits a markedly reduced donating ability, which led to the formation of transiently stable Pd^III and Pd^IV complexes, and consequently the corresponding O₂ oxidation reactivity and the subsequent C-C bond formation was improved significantly.</p>

3-Methyl-1-tosyl-1H-indole-2-carbaldehyde

The title indole derivative, C17H15NO3S, crystallizes with two independent molecules in the asymmetric unit. The benzene ring of the tosyl group is almost perpedicular to the indole ring in both molecules, with interplanar angles of 82.60 (5)° and 81.82 (6)°. The two molecules are, as a consequence, able to form an almost centrosymmetric non-bonded dimer, in which the molecules are linked by pairs of C—H...π interactions. The crystal structure displays a three-dimensional network of C—H...O interactions. A π–π interaction occurs between inversion-related indole rings with a centroid–centroid distance of 3.6774 (16) Å and an interplanar angle of 1.53 (15)°. This interaction leads to a stacking of molecules along theaaxis.