Synthesis, In-vitro evaluation and molecular docking studies of oxoindolin phenylhydrazine carboxamides as potent and selective inhibitors of ectonucleoside triphosphate diphosphohydrolase (NTPDase).

Members of the ectonucleoside triphosphate diphosphohydrolases (NTPDases) constitute the major family of enzymes responsible for the maintenance of extracellular levels of nucleotides and nucleosides by catalyzing the hydrolysis of nucleoside triphosphate (NTP) and nucleoside diphosphates (NDP) to nucleoside monophosphate (NMP). Although, NTPDase inhibitors can act as potential drug candidates for the treatment of various diseases, there is lack of potent as well as selective inhibitors of NTPDases. The current study describes the synthesis of a number of carboxamide derivatives that were tested on recombinant human (h) NTPDases. The most promising inhibitors were 2h (h-NTPDase1, IC50: 0.12 ± 0.03 µM), 2d (h-NTPDase2, IC50: 0.15 ± 0.01 µM) and 2a (h-NTPDase3, IC50: 0.30 ± 0.04 µM; h-NTPDase8, IC50: 0.16 ± 0.02 µM). Four compounds (2e, 2f, 2g and 2h) were associated with the selective inhibition of h-NTPDase1 while 2b was identified as a selective h-NTPDase3 inhibitor. Considering the importance of NTPDase3 in the regulation of insulin release, the NTPDase3 inhibitors were further investigated to elucidate their role in the insulin release. The obtained data suggested that compound 2a was actively participating in regulating the insulin release without producing any effect on NTPDase3 mRNA. Moreover, the most potent inhibitors were docked within the active site of respective enzyme and the observed interactions were in compliance with in vitro results. Hence, these compounds can be used as pharmacological tool to further investigate the role of NTPDase3 coupled to insulin release.

Phenylhydrazides as inhibitors of Leishmania amazonensis arginase and antileishmanial activity.

Searching for new substances with antileishmanial activity, we synthesized and evaluated a series of α,α-difluorohydrazide and α,α-difluoramides against Leishmania amazonensis arginase (LaArg). Four α,α-difluorohydrazide derivatives showed activity against LaArg with Ki in the range of 1.3-26 µM. The study of the kinetics of LaArg inhibition showed that these substances might act via different inhibitory mechanisms or even by a combination of these. The compounds were tested against L. amazonensis promastigotes and the best result was obtained to the compound 4 (EC50 of 12.7 ±â€¯0.3 µM). In addition, in order to obtain further insight into the binding mode of such compounds, molecular docking studies were performed to obtain additional validation of experimental results. Considering these results, it is possible to conclude that α,α-difluorohydrazide derivatives are a promising scaffold in the development of new substances against the etiological agent of leishmaniasis by targeting LaArg.

QSAR studies of phenylhydrazine-substituted tetronic acid derivatives based on the 1 H NMR and 13 C NMR chemical shifts.

The quantitative structure-activity relationship models of 40 phenylhydrazine-substituted tetronic acid derivatives were established between the 1 H nuclear magnetic resonance (NMR) and 13 C NMR chemical shifts and the antifungal activity against Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis, and Colletotrichum capsici. The models were validated by R, R2 , RA2 , variance inflation factor, F, and P values testing and residual analysis. It was concluded from the models that the 13 C NMR chemical shifts of C8, C10, C7, and the 1 H NMR chemical shifts of Ha contributed positively to the activity against Fusarium graminearum, Botrytis cinerea, Colletotrichum capsici, and Rhizoctonia cerealis, respectively. The models indicated that decreasing the election cloud density of specific nucleuses in compounds, for example, by the substituting of electron withdrawing groups, would improve the antifungal activity. These models demonstrated the practical application meaning of chemical shifts in the quantitative structure-activity relationship study. Furthermore, a practical guide was provided for further structural optimization of the antifungal phenylhydrazine-substituted tetronic acid derivatives based on the 1 H NMR and 13 C NMR chemical shifts.

Discovery and structure-activity relationships of phenyl benzenesulfonylhydrazides as novel indoleamine 2,3-dioxygenase inhibitors.

A novel class of phenyl benzenesulfonylhydrazides has been identified as potent inhibitors of indoleamine 2,3-dioxygenase (IDO), and their structure-activity relationship was explored. Coupling reactions between various benzenesulfonyl chlorides and phenylhydrazides were utilized to synthesize the sulfonylhydrazides bearing various substituents. Compound 3i exhibited 61 nM of IC50 in enzymatic assay and 172 nM of EC50 in the HeLa cell. The computational study of 3i suggested that the major interactions between 3i and IDO protein are the coordination of sulfone and heme iron, the hydrogen bonding and hydrophobic interactions between 3i and IDO. This novel class of IDO inhibitor provides a new direction to discover effective anti-cancer agents.

Direct catalytic asymmetric reductive amination of simple aromatic ketones.

A green method for chiral amine synthesis, the direct catalytic asymmetric reductive amination, was developed. Phenylhydrazide is an ideal nitrogen source for reductive amination. Molecular sieves play dual roles in this reaction. They help to remove H2O to form imine, as well as promote an imine reduction. f-Binaphane minimizes the inhibition effect from amines and helps the coordination of sterically demanding imines to the iridium center, thus leading to a smooth reaction.

The optical properties, synthesis and characterization of novel 5-aryl-3-benzimidazolyl-1-phenyl-pyrazoline derivatives.

A series of novel 5-aryl-3-benzimidazolyl-1-phenyl-pyrazoline derivatives were synthesized by the reaction of benzimidazolyl chalcone and phenylhydrazine in 41-72% yields. The compounds were characterized using IR, (1)H NMR and HRMS. Absorption and fluorescence spectra were measured in different organic solvent. An intense absorption maxima was noted at ca. 370 nm and emission maxima was noted at ca. 460 nm. The absorption spectra of the pyrazoline derivatives reveal that 5-aryl group attached to the pyrazoline ring hardly influenced the maximum absorption. The fluorescence spectra of these compounds indicated the emission wavelength was red shifted and the fluorescence intensity was decreased with the increase in solvent polarity.

Novel antimicrobial organic thermal stabilizer and co-stabilizer for rigid PVC.

Biologically active N-benzoyl-4-(N-maleimido)-phenylhydrazide (BMPH) was synthesized and its structure was confirmed by elemental analysis and various spectral tools. It was examined as a thermal stabilizer and co-stabilizer for rigid poly (vinyl chloride) at 180 °C in air. Blending BMPH with reference samples in different ratios greatly lengthens the thermal stability value and improves the extent of discoloration of PVC. TGA confirmed the improved stability of PVC in presence of the investigated organic stabilizer. GPC measurements were done to investigate the changes occurred in the molecular masses of the degraded samples of blank PVC and PVC in presence of the novel stabilizer. BMPH showed good antimicrobial activity towards two kinds of bacteria and two kinds of fungi.

Characterisation of hydrazides and hydrazine derivatives as novel aspartic protease inhibitors.

Virtual screening of an in-house virtual library of synthetic compounds using FlexX, followed by enzyme inhibition, identified hydrazide and hydrazine derivatives as novel aspartic protease inhibitors. These compounds inhibited human cathepsin D and Plasmodium falciparum plasmepsin-II with low micromolar concentrations (IC(50) = 1-2.5 microM). Modelling studies with plasmepsin-II predicted binding of ligands at the centre of the extended substrate-binding cleft, where hydrazide/hydrazine parts of the inhibitors acted as the transition state mimic by forming electrostatic interactions with catalytic aspartates.

A simple and efficient colorimetric anion receptor for H(2)PO(4)(-).

A novel and neutral anion sensor bearing a urea group as binding sites and 2,4-di nitrophenylhydrazine unit as a molecular architecture and a chromophore was synthesized and the visible color changes, the UV-vis and (1)H NMR spectral responses toward anions were assessed.

4-(9-fluorenylmethyloxycarbonyl)phenylhydrazine (FmPH): a new chromophoric reagent for quantitative monitoring of solid-phase aldehydes(1-3).

A direct method for quantifying solid-phase aldehydes has been developed, using a new reagent, 4-(9-fluorenylmethyloxycarbonyl)phenylhydrazine (FmPH). The FmPH reagent was synthesized in three steps (24% overall yield) from commercially available p-hydrazinobenzoic acid. Resin-bound aldehydes reacted quantitatively with FmPH, in the presence of trimethylorthoformate (TMOF) as a dehydrating agent, to form a highly conjugated, immobilized FmPH-hydrazone. Next, mild treatment of the hydrazone with an excess of piperidine-N,N-dimethylformamide (1:1) released the piperidine-dibenzofulvene adduct chromophore (epsilon(301nm) = 7800 M(-1) cm(-1)) from the support. FmPH quantitation of aldehydes proved to be a straightforward, sensitive, and reproducible technique for monitoring resin-bound aldehydes [albeit insufficiently reactive to allow reliable quantification of ketones]. The FmPH aldehyde assay is applicable to a range of solid supports, as demonstrated specifically for poly(ethylene glycol)-polystyrene (PEG-PS), aminomethylpolystyrene (AMP), and cross-linked ethoxylate acrylate resin (CLEAR).

Reaction of 3-acetonyl-5-cyano-1,2,4-thiadiazole with phenylhydrazine hydrochlorides: indolization and phenylpyrazolation.

Treatment of 3-acetonyl-5-cyano-1,2,4-thiadiazole (1) with 4-methyl or 4-methoxyphenylhydrazine hydrochloride provided 5-cyano-3-(2,5-dimethylindol-3-yl)-1,2,4-thiadiazole (2) or 5-cyano-3-(5-methoxy-2-methylindol-3-yl)-1,2,4-thiadiazole (3) as the sole product, respectively. In contrast, treatment of 1 with phenylhydrazine hydrochloride resulted in the formation of 5-cyano-3-(2-methylindol-3-yl)-1,2,4-thiadiazole (4) and the unexpected 5-cyano-3-(3,5-dimethyl-1-phenylpyrazol-4-yl)-1,2,4-thiadiazole (5). In a similar manner, when 1 was treated with 4-chlorophenylhydrazine hydrochloride, indolization was suppressed by phenylpyrazolation giving rise to 5-cyano-3-(5-chloro-2-methylindol-3-yl)-1,2,4-thiadiazole (6) and 5-cyano-3-[1-(4-chlorophenyl)-3,5-dimethylpyrazol-4-yl]-1,2,4-thia diazole (7). The reaction mechanism is discussed. Compounds 4, 5 and 6 exhibited weak antimicrobial activity against Helicobacter pylori.

[Lipoxygenase inhibitors. 3. Synthesis of tetrahydrobenzazepinone phenylhydrazones]. / Lipoxygenase-Inhibitoren, 3. Mitt.: Synthese von Tetrahydrobenzazepinon-phenylhydrazonen.

Tetrahydro-2H-benz[b]azepin-2-ones as starting substances are synthesized by Beckmann rearrangement of Schmidt reaction. The tetrahydrobenzazepinones are transformed into the thiones, thiolactim ethers and phenylhydrazones. The compounds are tested as inhibitors of soja lipoxygenase.

[Synthesis of 4-aryl-1-lambda-2, 2-lambda- 4-dithia-3,4-diaza-buta-1,2-dienes, a new dithiadiazabutadiene system]. / Synthese von 4-Aryl-1 lambda 2,2 lambda 4-dithia-3,4-diaza-buta- 1,2-dienen, einem neuen Dithiadiazabutadien-System.

4-Aryl-1 lambda 2, 2 lambda 4-dithia-3,4-diaza-buta-1,2-dienes 1a-12a as representatives of a dithiadiazabutadiene structure in which sulphur occupies a different oxidation number are synthesized by reaction of diazotated acceptor-substituted aryl- and hetarylamines 1-12 with thiosulfates or disodium disulfide in strong acid solution. For some examples a first pharmacological test indicate an immune-stimulating effect. Analytical examination as well as MNDO calculation which give some mechanistical insight, supplements the new synthesis.

[Thiadiazolidines derivates as analytical reactants. Part XI. Synthesis and analytical properties of ATIDAREZ-beta and ATIDAREZ-gamma]. / Pochodne tiadiazoliloazowe jako odczynniki analityczne. XI. Synteza i wlasciwosci analityczne kwasów beta-rezorcyloazoaminotiadiazolowego (ATIDAREZ-beta) i gamma-rezorcyloazoaminotiadiazolowego (ATIDAREZ-gamma).

New complex-forming azodyes were synthesized: 2-amine-5-(2',4'-dihydroxy-5'-carboxyphenylazo-1')-1,3,4-thiadiazol (ATIDAREZ-beta) and 2-amine-5-(2',4'-dihydroxy-3-carboxyphenylazo-1')-1,3,4-thiadiazol (ATIDAREZ-gamma). Absorbance maximum of methanol solution occurs at lambda = 230 and 440 nm and the molar absorbance coefficient E(lambdamax) = 8000 and 25,000, respectively (ATIDAREZ-beta); lambda = 240 and 440 nm and E(lambdamax) = 10,200 and 21,600, respectively (ATIDAREZ-gamma). The determined dissociation constants--higher values for ATIDAREZ-gamma than for ATIDAREZ-beta--indicate a stronger interaction of -OH and -COOH group positioned (to ortho -COOH) side by side (of spectra IR analysis)--intra- and intermolecular hydrogen bonds (association). In reaction with metal ions the formation of chelate compounds with Fe3+, Fe2+, Co2+, Ni2+, Cu2+ was stated for ATIDAREZ-beta; Co2+, Cu2+ and Ni2+ with ATIDAREZ-gamma at the L:M molar ratio of 1:1, when M = Cu2+ (for ATIDAREZ-beta and gamma) and M = Ni2+ (for ATIDAREZ-gamma) or 2:1 for Co2+, Fe2+, Fe3+ and Ni2+ (ATIDAREZ-beta) and Co2+ (ATIDAREZ-gamma). ATIDAREZ-gamma complexes with Co2+ and Cu2+ and Ni2+ are more stable than that of ATIDAREZ-beta (except Ni2+ complex). The obtained results of determinations were compared with that of azodyes of the following series: 2-amine-1,3,4-thiadiazole (ATIDAN, ATIDAN-6S, ATIDAK, ATIDAR, ATIDAP), 1,3,4-thiadiazole (TIDAREZ-beta and gamma), benzimidazole (BIAREZ-beta and gamma).

Preparation of hydrazino-modified proteins and their use for the synthesis of 99mTc-protein conjugates.

The syntheses and protein linking properties of succinimidyl 4-hydrazinobenzoate hydrochloride (SHBH) and succinimidyl 6-hydrazinonicotinate hydrochloride (SHNH), two new heterobifunctional linkers which lead to hydrazino-modified proteins, are described. SHBH-modified proteins are unstable due to the presence of the phenylhydrazine moiety. This problem was overcome by synthesizing the hydrazinopyridine analogue SHNH, and the conjugates derived from this linker are stable. Tc(V) oxo precursors readily add to hydrazinopyridine-modified proteins to yield the desired 99mTc-radiolabeled protein. 99mTc-hydrazinopyridine-polyclonal IgG conjugates are useful agents for the imaging of focal sites of infection.

Soybean lipoxygenases-1, -2a, -2b and -2c do not contain PQQ.

Soybean isoenzymes lipoxygenases-1, -2a, -2b and -2c were examined spectroscopically for the presence of covalently bound pyrrolo quinoline quinone (PQQ) after derivatization by phenylhydrazine (PH), 2,4-dinitrophenylhydrazine (DNPH) and 3-methyl-2-benzothiazolinone hydrazone (MBTH). DNPH derivatization of PQQ after a pronase digestion step of lipoxygenase-1 in the presence of an anion exchange gel fixing the cofactor was also investigated. None of these experiments provided evidence for the presence of PQQ contrary to previous report by Van der Meer et al (1). We have checked, by EPR spectroscopy, that the three reactants used were able to reduce the active site ferric iron. Our results were confirmed by the absence of enzyme inhibition by cis- and trans-1,2-diaminocyclohexane or benzylamine in the presence of NaBH3CN which have been reported to react with PQQ and to inactivate quinoproteins (2,3).