A novel proton transfer salt of 2-amino-6-sulfamoylbenzothiazole and its metal complexes: the evaluation of their inhibition effects on human cytosolic carbonic anhydrases.

A novel proton transfer compound (SMHABT)+(HDPC)- (1) obtained from 2-amino-6-sulfamoylbenzothiazole (SMABT) and 2,6-pyridinedicarboxylic acid (H2DPC) and its Fe(III), Co(II), Ni(II) complexes (2-4), and Fe(II) complex of SMABT (5) have been prepared and characterized by spectroscopic techniques. Additionally, single crystal X-ray diffraction techniques were applied to complexes (2-4). All complexes (2-4) have distorted octahedral conformations and the structure of 5 might be proposed as octahedral according to spectral and analytical results. All compounds, including acetazolamide (AAZ) as the control compound, were also evaluated for their in vitro inhibition effects on human hCA I and hCA II for their hydratase and esterase activities. The synthesized compounds have remarkable inhibitory activities on hCA I and hCA II. Especially, the inhibition potentials of the salt and the metal complexes (1-5) are comparable with AAZ. Inhibition data have been analyzed by using a one-way analysis of variance for multiple comparisons (p < .0001).

Synthesis and characterization of complexes of a novel proton transfer salt and their inhibition studies on carbonic anhydrase isoenzymes.

A novel proton transfer compound (HClABT)(+)(HDPC.H2DPC)(-) (1) and its Fe(III), Co(II), Ni(II) and two different Cu(II) complexes (2-6) have been prepared and characterized by spectroscopic techniques. Additionally, single crystal X-ray diffraction techniques were applied to all complexes. All compounds, including acetazolamide (AAZ) as the control compound, were also evaluated for their in vitro inhibition effects on human hCA I and hCA II for their hydratase and esterase activities. Although there is no inhibition for hydratase activities, all compounds have inhibited the esterase activities of hCA I and II. The comparison of the inhibition studies of 1-6 to parent compounds, ClABT and H2DPC, indicates that 1-6 have superior inhibitory effects. The inhibition effects of 2-6 are also compared to the inhibitory properties of the simple metal complexes of ClABT and H2DPC, revealing an improved transfection profile. Data have been analysed by using a one-way analysis of variance for multiple comparisons.

Synthesis and characterization of some metal complexes of a proton transfer salt, and their inhibition studies on carbonic anhydrase isozymes and the evaluation of the results by statistical analysis.

A novel proton transfer compound (HMeOABT)(+) (HDPC)(-) (1) and its Fe(III), Co(II), Ni(II) and Cu(II) complexes (2-5) have been prepared and characterized by spectroscopic techniques. Complex 4 has distorted octahedral conformation revealed by single crystal X-ray diffraction method. Structures of the other complexes might be proposed as octahedral according to experimental data. All compounds were also evaluated for their in vitro inhibition effects on hCA I and II for their hydratase and esterase activities. Although there is no inhibition for hydratase activities, all compounds have inhibited the esterase activities of hCA I and II. Data have been analyzed by using a one-way analysis of variance. The comparison of the inhibition studies of 1-5 to parent compounds indicates that 1-5 have superior inhibitory effects. The inhibition effects of 2-5 are also compared to inhibitory properties of the metal complexes of MeOABT and H2DPC, revealing an improved transfection profile.

Synthesis and characterization of a proton transfer salt between 2,6-pyridinedicarboxylic acid and 2-aminobenzothiazole, and its complexes and their inhibition studies on carbonic anhydrase isoenzymes.

A novel proton transfer compound (HABT)(+)(Hdipic)(-) (1) obtained from ABT and H2dipic and its metal complexes (2-5) have been prepared and characterized by spectroscopic techniques. Single crystal X-ray diffraction method has also been applied to 2 and 5. While complex 2 has a distorted octahedral conformation, 5 exhibits a distorted square pyramidal structure. The structures of 3 and 4 might be proposed as octahedral according to experimental data. All compounds were also evaluated for their in vitro inhibition effects on hCA I and II for their hydratase and esterase activities. Although there is no inhibition for hydratase activities, all compounds have inhibited the esterase activities of hCA I and II. The comparison of the inhibition studies of 1-5 to parent compounds indicates that 1-5 have superior inhibitory effects. The inhibition effects of 2-5 are also compared to inhibitory properties of the metal complexes of ABT and H2dipic, revealing an improved transfection profile.

Synthesis and characterisation of two novel proton transfer compounds and their inhibition studies on carbonic anhydrase isoenzymes.

Two novel proton transfer compounds were prepared between 2,4-dichloro-5-sulphamoylbenzoic acid (lasamide) (Hsba) and ethylenediamine (en), namely ethane-1,2-diaminium 2,4-dichloro-5-sulphamoylbenzoate (1), and also between Hsba and 2-amino-3-methylpyridine (2-amino-3-picoline) (amp), namely 2-amino-3-methylpyridinium 2,4-dichloro-5-sulphamoylbenzoate (2). All these were characterised by elemental, spectral (IR and UV-vis), thermal analyses, and single crystal X-ray diffraction studies. Compounds 1 and 2 crystallised in the P-1 and P21/c space groups, respectively. Intermolecular non-covalent interactions, such as ion pairing, hydrogen bonding, and π-π stacking were observed for these ionic compounds. The free ligands Hsba, en and amp, the products 1 and 2, and acetazolamide (AAZ) as the control compound, were also evaluated for their in vitro inhibitor effects on the human carbonic anhydrase isoenzymes (hCA I and hCA II) purified from erythrocyte cells by affinity chromatography for their hydratase and esterase activities. The half maximal inhibitory concentration (IC(50)) values for products 1 and 2 with respect to hydratase activity are 0.15 and 0.32 µM for hCA I and 0.06 and 0.15 µM for hCA II, respectively. The IC(50) values of the same inhibitors for esterase activity are 0.13 and 0.8 µM for hCA I and 0.14 and 0.1 µM for hCA II, respectively. In relation to esterase activities, the inhibition equilibrium constants (Ki) were also determined and found to be 0.137 and 0.99 µM on hCA I and 0.157 and 0.075 µM on hCA II for 1 and 2, respectively. The comparison of the inhibition studies of the newly synthesised compounds 1 and 2 to the parent compounds Hsba and amp and also to AAZ indicated that 1 and 2 have an effective inhibitory activity on hCA I and II, and might be used as potential inhibitors.

Synthesis, characterization and antiglaucoma activity of a novel proton transfer compound and a mixed-ligand Zn(II) complex.

A novel proton transfer compound, pyridin-2-ylmethanaminium 2,4-dichloro-5-sulfamoylbenzoate (1), and a mixed-ligand Zn(II) complex, bis(2,4-dichloro-5-sulfamoylbenzoate)(2-aminomethylpyridine)aquazinc(II) monohydrate (2), have been synthesized from the same free ligands, which are 2,4-dichloro-5-sulfamoylbenzoic acid (Hsba) and 2-aminomethylpyridine (amp). They have been characterized by elemental, spectral ((1)H NMR, IR and UV-vis.) and thermal analyses. Additionally, magnetic measurement and single crystal X-ray diffraction technique were applied to compound 2. In the complex, Zn(II) ion exhibits a distorted octahedral configuration coordinated by O1 and O1(i) atoms of two mono dentante sba anions and N1, N2, N2(i) atoms of bidentante amp anion and a water molecule (O1w). The free ligands Hsba and amp, and the products 1 and 2, and acetazolamide (AAZ) as the control compound, were also evaluated for their in vitro inhibitor effects on human Carbonic Anhydrase isoenzymes (hCA I and hCA II) purified from erythrocyte cell by affinity chromatography for their hydratase and esterase activities. The IC(50) values of products 1 and 2 for hydratase activity are 0.26 and 0.13microM for hCA I and 0.30 and 0.15microM for hCA II, respectively. The IC(50) values of the same inhibitors for esterase activity are 0.32 and 0.045microM for hCA I and 0.29 and 0.23microM for hCA II, respectively. In relation to esterase activities, the inhibition equilibrium constants (K(i)) were also determined and found 0.25 and 0.058microM on hCA I and 0.22 and 0.24microM on hCA II for 1 and 2, respectively. The comparison of the inhibition studies of newly synthesized compounds 1 and 2 to parent compounds Hsba and amp and to AAZ indicated that 1 and 2 have effective inhibitory activity on hCA I and II, and might be used potential inhibitors.