New aromatic/heteroaromatic propanesulfonylhydrazone compounds: synthesis, physical properties and inhibition studies against carbonic anhydrase II (CAII) enzyme.

Some new aromatic/heteroaromatic propanesulfonylhydrazone derivatives (1-8) were synthesized and characterized by elemental analyses, FT-IR, (1)H NMR, (13)C NMR, LC/MS techniques. The geometry optimizations and spectral calculations were performed by using DFT/B3LYP/6-311G(d,p) basis set in Gaussian 09 program. The inhibition activities of the synthesized compounds on carbonic anhydrase II (CAII) isoenzyme have been investigated by comparing IC50 values. Acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide) AAZ, a clinically used in CAII inhibition has also been investigated as standard inhibitor. The best aromatic/heteroaromatic propanesulfonylhydrazone inhibitors of this isoform were o-aminobenzaldehydepropanesulfonylhydrazone (1) and thiophenecarboxyaldehyde propanesulfonylhydrazone (5) having the same IC50 (0.55 mM) value. The molecular descriptors for propanesulfonylhydrazones were obtained to develop structure activity relationship (SAR) model between experimental IC50 values and the molecular descriptors calculated by PM3-based SAR models in Hyperchem 8, respectively. The obtained models confirm the good carbonic anhydrase II (CAII) inhibition activity of the propanesulfonylhydrazone derivatives. The selected descriptors are sensitive both to the imine (CH=N) and NH2 groups that are responsible from higher activities of (1) and (5) in their series.

Screening of novel chemical compounds as possible inhibitors of carbonic anhydrase and photosynthetic activity of photosystem II.

Thirty novel chemical compounds were designed and synthesized expecting that they would be possible inhibitors. From this number eleven were organic bases, twenty-four were their organic derivatives and fourteen were metal complexes. Screening of these chemicals by their action on photosynthetic electron transfer (PET) and carbonic anhydrase (CA) activity (CAA) of photosystem II (PSII), α-CA, as well as ß-CA was done. Several groups were revealed among them. Some of them are capable to suppress either one, two, three, or even all of the measured activities. As example, one of the Cu(II)-phenyl sulfonylhydrazone complexes (compound 25) suppresses CAA of α-CA by 88%, CAA of ß-CA by 100% inhibition; CAA of PSII by 100% and the PSII photosynthetic activity by 66.2%. The Schiff base compounds (12, 15) and Cu(II)-phenyl sulfonylhydrazone complexes (25, 26) inhibited the CAA and PET of PSII significantly. The obtained data indicate that the PSII donor side is a target of the inhibitory action of these agents. Some physico- or electrochemical properties such as diffusion coefficient, number of transferred electrons, peak potential and heterogeneous standard rate constants of the compounds were determined in nonaqueous media. pKa values were also determined in nonaqueous and aqueous media. Availability in the studied group of novel chemical agents possessing different inhibitory activity allow in future to isolate the "active part" in the structure of the inhibitors responsible for different inhibitory mechanisms, as well as to determine the influence of side substituters on its inhibitory efficiency.

Cr(III), Fe(III) and Co(III) complexes of tetradentate (ONNO) Schiff base ligands: synthesis, characterization, properties and biological activity.

A series of metal complexes were synthesized from equimolar amounts of Schiff bases: 1,4-bis[3-(2-hydroxy-1-naphthaldimine)propyl]piperazine (bappnaf) and 1,8-bis[3-(2-hydroxy-1-naphthaldimine)-p-menthane (damnaf) with metal chlorides. All of synthesized compounds were characterized by elemental analyses, spectral (UV-vis, IR, (1)H-(13)C NMR, LC-MS) and thermal (TGA-DTA) methods, magnetic and conductance measurements. Schiff base complexes supposed in tetragonal geometry have the general formula [M(bappnaf or damnaf)]Cl.nH(2)O, where M=Cr(III), Co(III) and n=2, 3. But also Fe(III) complexes have octahedral geometry by the coordination of two water molecules and the formula is [Fe(bappnaf or damnaf)(H(2)O)(2)]Cl. The changes in the selected vibration bands in FT-IR indicate that Schiff bases behave as (ONNO) tetradentate ligands and coordinate to metal ions from two phenolic oxygen atoms and two azomethine nitrogen atoms. Conductance measurements suggest 1:1 electrolytic nature of the metal complexes. The synthesized compounds except bappnaf ligand have the antimicrobial activity against the bacteria: Escherichia coli (ATCC 11230), Yersinia enterocolitica (ATCC 1501), Bacillus magaterium (RSKK 5117), Bacillus subtilis (RSKK 244), Bacillus cereus (RSKK 863) and the fungi: Candida albicans (ATCC 10239). These results have been considerably interest in piperazine derivatives due to their significant applications in antimicrobial studies.