Isocoumarins: a new class of selective carbonic anhydrase IX and XII inhibitors.

Isocoumarins, isomeric to comarins which act as effective carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, were investigated for the first time as inhibitors of this enzyme. A series of 3-substituted and 3,4-disubstituted isocoumarins incorporating phenylhydrazone, 1-phenyl-pyrazole and pyrazolo-substituted pyrimidine trione/thioxo-pyrimidine dione moieties were investigated for their interaction with four human (h) CA isoforms, hCA I, II, IX and XII, known to be important drug targets. hCA I and II were not inhibited by these compounds, whereas hCA IX and XII were inhibited in the low micromolar range by the less bulky derivatives. The inhibition constants ranged between 2.7-78.9 µM against hCA IX and of 1.2-66.5 µM against hCA XII. As for the coumarins, we hypothesise that the isocoumarins are hydrolysed by the esterase activity of the enzyme with formation of 2-carboxy-phenylacetic aldehydes which act as CA inhibitors. Isocoumarins represent a new class of CA inhibitors.

Design and synthesis of novel 1,3-diaryltriazene-substituted sulfonamides as potent and selective carbonic anhydrase II inhibitors.

A series of novel 1,3-diaryltriazene-substituted sulfonamides was synthesized by reaction of diazonium salt of 4-amino benzenesulfonamide with substituted aromatic amines. The obtained 1,3-diaryltriazene-substituted sulfonamides were investigated as inhibitors of four selected human carbonic anhydrase (CA, EC 4.2.1.1) isoforms (hCA I, hCA II, hCA VII and hCA IX) are involved in various diseases such as glaucoma, epilepsy, retinitis pigmentosa, cancer, obesity, etc. All these sulfonamides were found to be potent inhibitors of the cytosolic isoform hCA II with low nanomolar to sub-nanomolar Kis in the range of 0.2-21.5 nM, as well as a moderate selectivity against other cytosolic isoforms hCA I and hCA VII, and great selectivity against membrane-bound isoform hCA IX was observed. Since hCA II is an important drug target for antiglaucoma agents and diuretics, these isoform-selective inhibitors may be considered of interest as tools for the development of new candidates for these conditions.

Isocoumarins incorporating chalcone moieties act as isoform selective tumor-associated carbonic anhydrase inhibitors.

Aim: A series of isocoumarin-chalcone hybrids were prepared and assays for the inhibition of four isoforms of human carbonic anhydrase (hCA; EC 4.2.1.1), hCA I, II, IX and XII. Materials & methods: Isocoumarin-chalcone hybrids were synthesized by condensing acetyl-isocoumarin with aromatic aldehydes. They did not significantly inhibit off-target cytosolic isoforms hCA I and II (KI >100 µM) but acted as low micromolar or submicromolar inhibitors for the tumor-associated isoforms hCA IX and XII. Results & conclusion: Our work provides insights into a new and scarcely investigated chemotype which provides interesting tumor-associated CA inhibitors, considering that some such derivatives like sulfonamide SLC-0111 are in advanced clinical trials for the management of metastatic advanced solid tumors.

A series of isocoumarin­chalcone hybrids was prepared and assays for the inhibition of four isoforms of the metalloenzyme carbonic anhydrase (CA; EC 4.2.1.1), i.e., human (h) isoforms hCA I, II, IX and XII. Isocoumarins were less investigated as inhibitors of this enzyme. Here we show that the isocoumarin­chalcone hybrids do not significantly inhibit the off-target cytosolic isoforms hCA I and II (K_Is >100 µM) but act as low micromolar inhibitors for the tumor-associated isoforms hCA IX and XII. Our work thus provides insights into a new and scarcely investigated chemotype which may provide interesting tumor-associated CA inhibitors, because some such compounds, e.g., the sulfonamide SLC-0111, are presently in advanced clinical trials for the management of metastatic advanced solid tumors.

Synthesis, characterization and thermal degradation kinetics of a new pyrazole derived methacrylate polymer, poly(1,3-diphenyl-1H-pyrazol-5-yl methacrylate).

A new pyrazole derived methacrylate monomer, 1,3-diphenyl-1H-pyrazol-5-yl methacrylate, was synthesized from the reaction of 1,3-diphenyl-5-pyrazolone with methacryloyl chloride in the presence of triethylamine. After that, its homopolymerization was carried out by free radical polymerization method at 60 °C initiated with benzoyl peroxide. Spectral characterizations were achieved by 1H-NMR and FTIR spectroscopies. The kinetics of thermal degradation of the new polymer, poly(1,3-diphenyl-1H-pyrazol-5-yl methacrylate), poly(DFPMA), were investigated by thermogravimetric analysis (TGA) at different heating rates. The initial decomposition temperature of the polymer changed from 216.3 °C to 243.5 °C depending on the increasing heating rate. The thermal decomposition activation energies in a conversion range of 7-19% were 79.45 kJ/mol and 81.56 kJ/mol by the Flynn-Wall-Ozawa and Kissinger methods, respectively. Thermodegradation mechanism of the poly(DFPMA) were investigated in detail by using different kinetic methods available in the literature such as Coats-Redfern, Tang, Madhusudanan and Van Krevelen. Among all these methods, the best result was obtained for Coats-Redfern method (E =90.93 kJ/mol) at the optimum heating rate of 15 °C/min for D1 mechanism. That means the thermodegradation mechanism of poly(DFPMA) proceeds over a one-dimensional diffusion type deceleration mechanism.

1-(3-Mesityl-3-methyl-cyclo-butyl)-2-phenoxy-ethanone.

In the title compound, C(22)H(26)O(2), the cyclo-butane ring is puckered, with a dihedral angle of 24.97 (9)° between the two C(3) planes. In the crystal, inter-molecular non-classical C-H⋯O inter-actions between the methyl-cyclo-butyl CH group and the O atom of the phen-oxy group are found.

A novel fluorescent probe based on isocoumarin for Hg2+ and Fe3+ ions and its application in live-cell imaging.

Synthesis of the 2-amino-4-phenyl-6- (isocoumarin-3-yl) -3-cyanopyridine (APICP) containing both isocoumarin and pyridine ring in its structure was carried out, and this compound was characterized by ATR-FTIR, 1H NMR, and 13C NMR spectral techniques. A fluorescence sensor determining Hg2+ and Fe3+ ions in DMSO/HEPES buffer solution (9/1 v/v, 5 µM, pH 7.0) was developed using the synthesized compound, and the detection limits of the sensor with exquisite selectivity were calculated as 8.12 nM and 5.51 nM for Hg2+ and Fe3+ ions, respectively. Jobs plot method was used to determine the stoichiometry of APICP-Hg2+/Fe3+ complexes as 2:1 and FT-IR and ESI-MS methods confirmed the results. Besides, cell growth inhibitory potentials of the sensor over HepG2 cells and in vivo fluorescent cell imaging experiments were conducted. Findings revealed the relatively low cytotoxic effects of the synthesized sensor (IC50: 0.541 ±â€¯0.039 mM), and it could be utilized as an intracellular imaging agent for the determination of Fe3+ and Hg2+ ions in biological systems.

Synthesis and antimicrobial activity of some novel derivatives of benzofuran: part 2. The synthesis and antimicrobial activity of some novel 1-(1-benzofuran-2-yl)-2-mesitylethanone derivatives.

The reaction of salicylaldehyde with 1-chloro-3-mesitylacetone (2) and potassium carbonate was used to prepare 1-(1-benzofuran-2-yl)-2-mesitylethanone (4) for the starting reagent purposes. 1-(1-Benzofuran-2-yl)-2-mesitylethanoneoxime (5) was synthesized by the reaction of the compound (4) with hydroxylamine. New derivative of 1-(1-benzofuran-2-yl)-2-mesitylethanoneoxime (5) as 1-(1-benzofuran-2-yl)-2-mesitylethanonesemicarbazone (7) was obtained in very high yields. Alkyl substituted N-oxime ethers (8a-d) were obtained by the reaction compound 5 and various halogen contained compounds. The compounds 9a-d were synthesized by the reaction of the compound (5) and four different acyl chlorides. Some of the synthesized compounds were tested for antimicrobial activity against Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Among the synthesized compounds (E)-1-(1-benzofuran-2-yl)-2-mesitylethanone-O-benzoyloxime (9b) was found the most active derivative against S. aureus ATCC 6538 and E. coli ATCC 25922. The other compounds exhibited moderate activity against the other test microorganisms.

Synthesis and oxidant properties of novel (5-bromobenzofuran-2-yl)(3-methyl-3-mesitylcyclobutyl)ketonethiosemicarbazone.

The reaction of 5-bromosalicylaldehyde with 1-mesityl-1-methyl-3-(2-chloro-1-oxoethyl)cyclobutane (1) and potassium carbonate was used to prepare (5-bromobenzofuran-2-yl)(3-methyl-3-mesitylcyclobutyl)methanone (2) for the starting reagent purposes. (5-Bromobenzofuran-2-yl)(3-methyl-3-mesitylcyclobutyl)ketonethiosemicarbazone (3) was synthesized from the reaction of the compound (2) with thiosemicarbazide. In the present study, it was aimed to examine the influence of synthetic (5-bromobenzofuran-2-yl)(3-methyl-3-mesityl cyclobutyl)ketonethiosemicarbazone on levels of vitamins (A, E, C), selenium and malondialdehyde in rats. A total of 42 rats were used and the animals were divided into two groups in the study. Only a subcutaneous injection of 250 microl of 75% ethanol was given to the control group every other day. A subcutaneous injection of this compound (25 mg kg-1, dissolved in 250 microl of 75% ethanol) was administered to the other group of rats. After the application of (5-bromobenzofuran-2-yl)(3-methyl-3-mesitylcyclobutyl)ketonethiosemicarbazone for 20 days, the serum vitamins (A, E, C) and malondialdehyde levels were determined with high performance liquid chromatography, the serum selenium level was determined by using fluorescence spectrophotometer. The serum vitamin A, E, C and selenium levels were significantly decreased compared to control group (P<0.005), whereas serum malondialdehyde levels were higher than control group levels (P<0.005). As a result, it could be suggested that this compound induced a severe stress, and also increased the amount of free radicals depending on the stress.

The synthesis and antimicrobial activity of some new methyl N-arylthiocarbamates, dimethyl N-aryldithiocarbonimidates and 2-arylamino-2-imidazolines.

Methyl N-arylthiocarbamates (2a-d) and dimethyl N-aryldithiocarbonimidates (2e-i) were synthesized from the reaction of aromatic amines with carbon disulfide and methyl iodide and NaOH in various quantitative amounts. 2-Arylamino-2-imidazolines (3a-i) were prepared by heating both methyl N-arylthiocarbamates (2a-d) and dimethyl N-aryldithiocarbonimidates (2e-i) with 1,2-diaminoethane under reflux. o-chlorobenzyl derivatives of [1,3,4]-thiadiazole-2-yl substituted aminoimidazoline compounds were synthesized by treatment of [1,3,4]-thiadiazole-2-yl substituted aminoimidazolines (3h-i) with 2-benzyl chloride in basic medium and DMSO. Some of the synthesized compounds were tested in vitro for their antimicrobial activity. All of the selected compounds showed some antimicrobial activity against test microorganisms. Compounds 2f and 3f which have 1,3-benzothiazol ring exhibited a weak activity against Candida globrata.

Synthesis and antimicrobial activity of some novel derivatives of benzofuran: part 1. Synthesis and antimicrobial activity of (benzofuran-2-yl)(3-phenyl-3-methylcyclobutyl) ketoxime derivatives.

The reaction of salicylaldehyde with 1-phenyl-1-methyl-3-(2-chloro-1-oxoethyl) cyclobutane (1) and potassium carbonate was used to prepare (benzofuran-2-yl)(3-methyl-3-phenylcyclobutyl) methanone (2) for the starting reagent purposes. (benzofuran-2-yl)(3-phenyl-3-methyl cyclobutyl) ketoxime (3) was synthesized from the reaction of the compound (2) with hidroxylamine. New derivatives of (benzofuran-2-yl)(3-phenyl-3-methyl cyclobutyl) ketoxime (3) such as, O-glycidylketoxime (4) and O-phenylacylketoxime (5a-c) were obtained very high yields. Alkyl, allyl and aryl substituted N-oxime ethers (6a-e) were obtained from the reaction compound 3 and various halogen contained compounds. The syntheses of the compounds (7a-f) were carried out from the reaction of the compound (4) and different amines such as, isopropyl amine, natrium azide, morpholine and piperazine. All of the synthesized compounds were tested for antimicrobial activity against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis ATCC 14153 and Candida albicans ATCC 10231. Among the synthesized compounds (benzofuran-2-yl)(3-phenyl-3-methyl cyclobutyl)-O-[2-hydroxy-3-(N-methylpiperazino)] propylketoxime (7d) was found the most active derivative against S. aureus ATCC 6538. The compounds 2, 5b, 6b, 6c, 7b and 7f showed very strong and the same antimicrobial effect against C. albicans ATCC 10231. Similarly (benzofuran-2-yl)(3-phenyl-3-methylcyclobutyl)-O-benzylketoxime 6a showed good antimicrobial effect against C. albicans ATCC 10231. None of the other compounds exhibited activity against the other test microorganisms.

Studies on the synthesis and reactivity of novel benzofuran-2-yl-[3-methyl-3-phenylcyclobutyl] methanones and their antimicrobial activity.

Preparation in excellent yields of cyclobutyl benzofuran-2-yl- and naphthofuran- 2-yl-ketones, the corresponding ketoximes and thiosemicarbazones, ether derivatives of the ketoximes and thiazoles derived from the thiosemicarbazones are described. Two of the synthesized compounds have been tested against eight different microorganisms and found to be active against some of the species studied.

Synthesis, reactivity and biological activity of novel bisbenzofuran-2-yl-methanone derivatives.

Preparation of bisbenzofuran-2-yl-methanone (1), the corresponding ketoxime 4, semicarbazone and thiosemicarbazone 3a and 3b, ether derivatives of the ketoximes 5a-j and the alcohol 2 are described. These substances have been prepared in excellent yields. All the synthesized compounds except 5i have been tested against five different microorganisms and some of them were found to be active against some of the species studied.

Spectral characterization of a newly synthesized fluorescent semicarbazone derivative and its usage as a selective fiber optic sensor for copper(II).

In this work photoluminescent properties of highly Cu(2+) selective organic fluoroionophore, semicarbazone derivative; bis(naphtho[2,1-b]furan-2-yl)methanone semicarbazone (BNF) was investigated in different solvents (dichloromethane, tetrahydrofuran, toluene and ethanol) and in polymer matrices of polyvinylchloride (PVC) and ethyl cellulose (EC) by absorption and emission spectrometry. The BNF derivative displayed enhanced fluorescence emission quantum yield, Q(f)=6.1 x 10(-2) and molar extinction coefficient, epsilon=29,000+/-65 cm(-1)M(-1) in immobilized PVC matrix, compared to 2.6 x 10(-3) and 24,573+/-115 in ethanol solution. The offered sensor exhibited remarkable fluorescence intensity quenching upon exposure to Cu(2+) ions at pH 4.0 in the concentration range of 1.0 x 10(-9) to 3.0 x 10(-4)M [Cu(2+)] while the effects of the responding ions (Ca(2+), Hg(+), Pb(2+), Al(3+), Cr(3+), Mn(2+), Mg(2+), Sn(2+), Cd(2+), Co(2+) and Ni(2+)) were less pronounced.

C-H...O, C-H...pi and pi-pi interactions in three benzofuran-2-yl ketone derivatives.

The molecules of 2-benzoyl-1-benzofuran, C15H10O2, (I), interact through double C-H...O hydrogen bonds, forming dimers that are further linked by C-H...O, C-H...pi and pi-pi interactions, resulting in a three-dimensional supramolecular network. The dihedral angle between the benzoyl and benzofuran fragments in (I) is 46.15 (3) degrees . The molecules of bis(5-bromo-1-benzofuran-2-yl) ketone, C17H8Br2O3, (II), exhibit C2 symmetry, with the carbonyl group (C=O) lying along the twofold rotation axis, and are linked by a combination of C-H...O and C-H...pi interactions and Br...Br contacts to form sheets. The stability of the molecular packing in 3-mesityl-3-methylcyclobutyl 3-methylnaphtho[1,2-b]furan-2-yl ketone, C28H28O2, (III), arises from C-H...pi and pi-pi stacking interactions. The fused naphthofuran moiety in (III) is essentially planar and makes a dihedral angle of 81.61 (3) degrees with the mean plane of the trimethylbenzene ring.

1,3-Dibenzoylimidazolidine-2-thione and 1,3-dibenzoyl-3,4,5,6-tetrahydropyrimidine-2(1H)-thione.

The title compounds, 1,3-dibenzoylimidazolidine-2-thione, C17H14N2O2S, (I), and 1,3-dibenzoyl-3,4,5,6-tetrahydropyrimidine-2(1H)-thione, C18H16N2O2S, (II), were obtained from the reactions of imidazolidine-2-thione and 1,4,5,6-tetrahydropyrimidine-2-thiol, respectively, with benzoyl chloride. Compounds (I) and (II) contain, respectively, imidazolidinethione [C=S = 1.6509 (14) A] and pyrimidinethione [C=S = 1.6918 (19) A] moieties bonded to two benzoyl rings. The molecules of (I) exhibit C2 symmetry, the C=S bond lying along the twofold rotation axis, while the molecules of (II) have mirror symmetry (Cs). The imidazolidine ring in (I) is essentially planar, while the pyrimidine ring in (II) adopts a boat conformation. Molecules of (I) are linked by weak intermolecular C-H...O interactions, while molecules of (II) are held together by van der Waals interactions.

(Benzofuran-2-yl)(3-methyl-3-phenylcyclobutyl)methanone.

The structure of the title compound, C20H18O2, consists of a dimeric arrangement of benzofuran molecules around an inversion centre, linked via C-H...O hydrogen bonds. There are also C-H...pi ring interactions. All these interactions result in the formation of infinite chains parallel to the [100] axis. The cyclobutane ring is puckered, with a dihedral angle of 29.03 (13) degrees between the two three-atom planes.