Synthesis of new dendrimers—trimesic acid derivatives

Synthesis of 4-sulfamoyl phenyl diazocarboxylic acid derivatives as novel non-classical inhibitors of human carbonic anhydrase II activity: an in vitro study

The first class of carbonic anhydrase inhibitors (CAIs) discovered was sulfonamides, but their clinical use is limited due to side effects caused by their inhibition of multiple CA isoforms. To overcome this, researchers have focused on developing isoform-selective CAIs. This study involved the synthesis and characterization of novel carboxylic acid/sulfonamide derivatives. We investigated the interaction between these compounds and the human carbonic anhydrase II (hCA II) isoform using spectroscopic and computational methods. The synthesized compounds were evaluated based on their IC50, Kd and Ki values, and it was found that the inhibitory potency and binding affinity of the compounds increased with the number of carboxylic acids zinc binding groups. Specifically, the compound C4, with three carboxylic acid groups, showed the strongest inhibitory potency. Fluorescence measurements revealed that all compounds quenched the intrinsic fluorescence of hCA II through a dynamic quenching process, and each compound had one binding site in the hCA II structure. Thermodynamic analysis indicated hydrogen bonds and van der Waals interactions played key roles in the binding of these compounds to hCA II. Docking studies showed that the carboxylic acid groups directly attached to the zinc ion in the active site, displacing water/hydroxide ions and causing steric hindrance. Overall, the strengthening of inhibitory activity and the binding power of these carboxylic acid derivatives for the hCA II makes these compounds interesting for designing novel hCA II inhibitors.Communicated by Ramaswamy H. Sarma.

Crystal structure of 2-methyl-1H-imidazol-3-ium 3,5-di-carb-oxy-benzoate

The structure of the title salt, C4H7N2 +·C9H5O6 - (1), is reported. The compound is built from a protonated 2-methyl-imidazole and a singly deprotonated trimesic acid. Detailed analysis of bond distances and angles for both ions reveals subtle differences compared with their neutral mol-ecule counterpart. Analysis of the crystal packing in compound 1 reveals the formation of undulating chains by the ions through hydrogen bonding. The chains stack along the b axis through π-π inter-actions and inter-connect with other chains in an out-of-phase arrangement along the ac plane through further hydrogen-bonding inter-actions.

A Fast and Convenient Synthesis of New Water-Soluble, Polyanionic Dendrimers

Reasonably simple, efficient, and possessing aspects of generality, the methodology for the synthesis of new, water-soluble, dendrimeric polyesters with great potential applications as antiviral drugs in their own right is described. The essential aspect of the presented approach is a quite unique, immediate access to the polyanionic material at each generation during divergent synthesis. Six target polyanionic dendrimers (generations 1, 2, and 3) have been synthesized. The key monomers applied in this project were 1,3,5-benzenetricarboxylic acid derivatives, which also worked as direct precursors of the charged dendrimer surface.

Dendrimers as efficient nanocarriers for the protection and delivery of bioactive phytochemicals

The genesis of dendrimers can be considered as a revolution in nano-scaled bioactive delivery systems. These structures possess a unique potential in encapsulating/entrapping bioactive ingredients due to their tree-like nature. Therefore, they could swiftly obtain a valuable statue in nutraceutical, pharmaceutical and medical sciences. Phytochemicals, as a large proportion of bioactives, have been studied and used by scholars in several fields of pharmacology, medical, food, and cosmetic for many years. But, the solubility, stability, and bioavailability issues have always been recognized as limiting factors in their application. Therefore, the main aim of this study is representing the use of dendrimers as novel nanocarriers for phytochemical bioactive compounds to deal with these problems. Hence, after a brief review of phytochemical ingredients, the text is commenced with a detailed explanation of dendrimers, including definitions, types, generations, synthesizing methods, and safety issues; then is continued with demonstration of their applications in encapsulation of phytochemical bioactive compounds and their active/passive delivery by dendrimers. Dendrimers provide a vast and appropriate surface to entrap the targeted phytochemical bioactive ingredients. Several parameters can affect the yield of nanoencapsulation by dendrimers, including their generation, type of end groups, surface charge, core structure, pH, and ambient factors. Another important issue of dendrimers is related to their toxicity. Cationic dendrimers, particularly PAMAM can be toxic to body cells through attaching to the cell membranes and disturbing their functions. However, a number of solutions have been suggested to decrease their toxicity.

Characterisation and Evaluation of Trimesic Acid Derivatives as Disulphide Cross-Linked Polymers for Potential Colon Targeted Drug Delivery

Discovery and use of biocompatible polymers offers great promise in the pharmaceutical field, particularly in drug delivery systems. Disulphide bonds, which commonly occur in peptides and proteins and have been used as drug-glutathione conjugates, are reductively cleaved in the colon. The intrinsic stability of a disulphide relative to thiol groups is determined by the redox potential of the environment. The objective of this study was to synthesise a trimesic acid-based disulphide cross-linked polymer that could potentially be used for targeted delivery to the colon. The monomer was synthesised by an amide coupling reaction between trimesic acid and (triphenylmethyl) thioethylamine using a two-step synthesis method. The s-trityl group was removed using a cocktail of trifluoroacetic acid and triethylsilane to expose the thiols in preparation for further polymerisation. The resulting polymers (P10, P15, P21, P25, and P51, generated using different molar ratios) were reduced after 1.5 h of reduction time. Scanning electron microscopy images of the polymers showed spherical, loose, or tight patterns depending on the molar ratio of polymerisation. These polymers also exhibited efficient dissolution under various gastrointestinal conditions. Of the five polymers tested, P10 and P15 appeared to be promising drug delivery vehicles for poorly soluble drugs, due to the hydrophobic nature of the polymers.

1-Aminobenzocyclobutene-1-phosphonic Acid and Related Compounds as Inhibitors of Phenylalanine Ammonia-Lyase

Five new geminal aminocycloalkanephosphonic acids (4 - 8) containing both an aromatic ring and a cycloalkane ring were synthesized and evaluated as potential inhibitors of buckwheat phenylalanine ammonia-lyase (PAL). Within the set of compounds which are related to 2-aminoindane-2-phosphonic acid (AIP, 3), a known powerful inhibitor of PAL, racemic 1-aminobenzocyclobutene-1-phosphonic acid (4), was six times weaker than AIP as an in vitro inhibitor of buckwheat PAL, but six times stronger than AIP as an in vivo inhibitor of phenylalanine-derived anthocyanin synthesis in buckwheat.