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PubMed2001

Synthesis and structure-activity relationships of benzophenone hydrazone derivatives with insecticidal activity.

A broad range of benzophenone hydrazone derivatives was prepared and tested against selected chewing insect pests, allowing the analysis of structure-activity relationships. Good activity was found only when the aromatic rings were substituted at the 4-positions with an halogen atom and a triflate or perhaloalkoxy group. In contrast, a number of substituents on the hydrazone part led to active compounds, the best results being achieved with acyl-type substituents. The excellent laboratory and greenhouse activity of the best representatives was confirmed in semi-field trials against Spodoptera littoralis.

Animals↗
PubMed1988

In vitro kinetic studies of the reaction of hydralazine and its acetone hydrazone with pyruvic acid.

To understand the reaction between hydralazine (HP) or its acetone hydrazone (HAH), a metabolite of HP and pyruvic acid, a new selective HPLC method for simultaneous determination of HP, HAH, and hydralazine pyruvic acid hydrazone (HPH) was developed. In vitro degradation of HAH and formation of HP and HPH were investigated at pH 7.4 and 37 degrees C in the presence or absence of pyruvic acid. Hydralazine degraded slowly according to an apparent first-order rate (7.46 x 10(-2)h-1). The degenerative reaction of HAH, accompanied by simultaneous hydrolysis to the parent drug HP, was also subject to apparent first-order loss (3.00 x 10(-1)h-1). In addition, HAH was partly converted to HP and HPH in the presence of pyruvic acid. For the formation pathway of HPH, a model that included the direct reaction of HAH with pyruvic acid and the secondary formation mediated by back-conversion to HP gave a better fit to the experimental data than the model consisting of the latter reaction only. About 10% of the HPH formed was generated by the direct reaction of HAH with pyruvic acid, based on the rate constants estimated. These results suggest that the formation of HPH is not all accomplished through back-conversion to HP.

Chemical Phenomena↗
PubMed1992

Bis-daunomycin hydrazones: interactions with DNA.

A series of bis-daunomycin hydrazones were synthesised from diester diamide linking groups derived from alpha,omega-dicarboxylic acids. All members of the series bis-intercalated into DNA, as evidenced by doubling of the lengthening of rod-like DNA compared to daunomycin, and by a 1000-5000 fold slower dissociation from DNA than daunomycin under detergent sequestration conditions. The bis-hydrazones exhibited neighbour exclusion, and occupied 6 bp under saturating conditions of drug. A unique DNA sequence specificity was apparent from transcriptional footprinting of 100 bp of DNA, with the greatest preference for 5'-CACA sites.

Animals↗
PubMed1981

A novel preparation of human platelet lipoxygenase. Characteristics and inhibition by a variety of phenyl hydrazones and comparisons with other lipoxygenases.

Acetone-pentane powder preparations of human blood platelets were prepared and the characteristics of the 12L-lipoxygenase were studied using measurements of oxygen consumption. No sharp pH optimum with equal reaction velocities was observed over a range of pH 7.5-8.5 in a variety of buffers. The enzyme could be easily solubilized in 1% deoxycholate, and in this form was moderately stable to heat. Of 10 divalent cations tested at a concentration of 3.7 . 10(-3) M, only zinc and tin were inhibitory. None of he other ions was stimulatory. The products of the oxidation of arachidonate were characterized from both soluble and insoluble enzyme preparations. With the insoluble suspension, 55% of the added arachidonate was recovered as 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) and 27% appeared as trihydroxyeicosatetraenoic acid isomers (THETEs). With the soluble preparation, 84% of the arachidonate appeared as 12-HETE and only 5% as THETEs. The Michaelis constants for dihomo-gamma-linolenic aicd, arachidonic acid, and eicosapentaenoic acid substrates are presented. A series of phenyl hydrazone inhibitors of various structural types were discovered to be potent inhibitors of the human platelet lipoxygenase. The sensitivities of this enzyme to these inhibitors were compared to soybean lipoxygenase and sheep seminal vesicular cyclodioxygenase. In general, the soybean enzyme was most sensitive; the sheep seminal vesicular cyclodioxygenase was the least sensitive and the human platelet lipoxygenase was intermediate between the two. The Ki values for two phenyl hydrazone inhibitors with both soybean and human platelet lipoxygenases is presented.

Arachidonic Acids↗
PubMed2006

Mechanistic differences between in vitro assays for hydrazone-based small molecule inhibitors of anthrax lethal factor.

A systematically generated series of hydrazones were analyzed as potential inhibitors of anthrax lethal factor. The hydrazones were screened using one UV-based and two fluorescence-based in vitro assays. The study identified several inhibitors with IC50 values in the micromolar range, and importantly, significant differences in the types of inhibition were observed with the different assays.

Aldehydes↗
PubMed2005

Kinetic model studies on the chemical ligation of oligonucleotides via hydrazone formation.

We report on the suitability of hydrazone formation for activator-free ligation of oligonucleotides. 5'-Acyl hydrazides were synthesized using a previously described phosphoramidite modifier, whereas 3'-hydrazides resulted from a hydrazinolysis of an ester group serving as a linker to the solid support. Aromatic aldehydes could be directly introduced on the 5'-terminus via the respective phosphoramidates. Aliphatic aldehydes were generated by periodate cleavage of the corresponding 3'- and 5'-modified diol precursors. Ligation of a 3'-hydrazide-modified oligonucleotide with oligonucleotides bearing an aromatic aldehyde in 5'-position showed a fast reaction kinetics (k(1) about 10(-1) M(-1)s(-1)) [corrected] and irreversible hydrazone formation. The ligation of a 5'-hydrazide-modified oligonucleotide and a 3'-ribobisaldehyde appeared to proceed reversibly at the beginning, but became irreversible with increasing reaction time. Hydrazide-modified oligonucleotides were found to be somewhat unstable in aqueous solutions.

Combinatorial Chemistry Techniques↗
PubMed2005

HPLC study on stability of pyridoxal isonicotinoyl hydrazone.

Biocompatible iron chelators are currently under extensive investigation as promising drug candidates. Pyridoxal isonicotinoyl hydrazone (PIH) is a lead compound of the aroylhydrazone group of novel iron chelating agents. In this study, the precise and accurate HPLC analytical methods were used for the stability evaluation of water-soluble PIH salt (PIH x 2HCl) in aqueous media of different pH (2.0, 3.9, 7.0, 9.0 and 12.0) as well as in two selected pharmaceutical co-solvents at both laboratory and elevated (40 degrees C) temperatures. The susceptibility of PIH x 2HCl to oxidative decomposition was studied in the solutions of hydrogen peroxide (3 and 30%). Furthermore, the solid substance of PIH x 2HCl was exposed to UV, dry and wet heat. Our experiments revealed that PIH was considerably sensitive to hydrolytic decomposition in aqueous media, resulting in the splitting of the hydrazone bond. The elevated temperature significantly accelerated the hydrolytic reaction. The lowest rate of hydrolysis of PIH was observed in the phosphate buffer of pH 7.0 and in the pharmaceutical co-solvents (30% PEG-300 and 10% Cremophor EL). No special degradation products were detected in the samples exposed to either hydrogen peroxide or co-solvents. The solid substance of PIH x 2HCl was stable when exposed to UV, dry or wet heat for 33 h.

Calibration↗
PubMed2005

Synthesis and spectral characterization of ternary complexes of oxovanadium(IV) containing some acid hydrazones and 2,2'-bipyridine.

An interesting series of heterocyclic base adducts of oxovanadium(IV) complexes have been synthesized by the reaction of vanadium(IV) oxide acetylacetonate with some hydrazones (H(2)L) in the presence of a heterocyclic base 2,2'-bipyridine. The compounds were characterized by analytical and different physico-chemical techniques like IR, electron paramagnetic resonance (EPR) and UV-Vis spectral studies and magnetic studies. The EPR spectra indicate that the free electron is in the d(xy) orbital. The coordination geometry around oxovanadium(IV) in all complexes is octahedral, with one dibasic tridentate ligand L(2-), and one bidentate heterocyclic base. The IR spectra suggest that coordination takes place through azomethine nitrogen and enolate oxygen from the hydrazide moiety and phenolate oxygen. The pyridyl nitrogens of the hydrazones, H(2)L(2) and H(2)L(4) are not involved in the coordination. The molar conductivities show that all the complexes are non-electrolytes. All electronic transitions were assigned. All the compounds are paramagnetic. EPR studies of all compounds suggest axial symmetry. The calculated bonding parameters indicate that in-plane sigma bonding is more covalent than in-plane pi bonding.

2,2'-Dipyridyl↗
PubMed2006

Synthesis, spectroscopic, thermal and antifungal studies on lanthanum(III) and praseodymium(III) derivatives of 1,1-diacetylferrocenyl hydrazones.

A series of new coordination complexes of La(III) and Pr(III) with hydrazones, derived from 1,1-diacetylferrocene and different aromatic acid hydrazides have been synthesized and characterized by elemental analyses, electrical conductance, magnetic moment, IR, (1)H NMR, UV-vis spectra and molar conductance. The thermal behaviour of the complexes under non-isothermal condition was investigated by TG and DTG techniques. The antifungal activity of hydrazones and their corresponding complexes were also investigated.

Antifungal Agents↗
PubMed2000

Protection of erythrocytes against oxidative damage and autologous immunoglobulin G (IgG) binding by iron chelator fluor-benzoil-pyridoxal hydrazone.

Iron is released in a free desferrioxamine-chelatable form when erythrocytes are challenged by an oxidative stress. The release of iron is believed to play an important role in inducing destructive damage (lipid peroxidation and hemolysis) or in producing membrane protein oxidation and generation of senescent cell antigens (SCA). In this report, we further tested the hypothesis that intracellular chelation of iron released under conditions of oxidative stress prevents erythrocyte damage or SCA formation. Fluor-benzoil-pyridoxal hydrazone (FBPH), an iron-chelating molecule of the family of aromatic hydrazones, was prepared by synthesis and used for the above purpose after the capacity of the product to enter cells had been ascertained. GSH-depleted mouse erythrocytes were incubated with the oxidant drug phenylhydrazine in order to produce iron release, lipid peroxidation, and hemolysis. FBPH at a concentration of 200 microM prevented lipid peroxidation and hemolysis in spite of equal values of iron release. FBPH was active even at a lower concentration (100 microM) when the erythrocytes were preincubated with it for 15 min. No preventive effect was seen when FBPH saturated with iron was used. Prolonged aerobic incubation (60 hr) of erythrocytes produced iron release and formation of SCA as determined by autologous immunoglobulin G (IgG) binding. The IgG binding was detected by using an anti-IgG antibody labeled with fluorescein and by examining the cells for fluorescence by confocal microscopy. FBPH prevented SCA formation in a dose-related manner. These results lend further support to the hypothesis that iron release is a key factor in erythrocyte ageing.

Animals↗
PubMed2003

Sugar hydrazone-metal complexes: transition- and non-transition metal complexes of monosaccharide S-alkylhydrazonecarbodithioates and dehydro-L-ascorbic acid bis(S-alkylhydrazonecarbodithioates).

Copper(II), nickel(II) and palladium(II) complexes with aldehydo-D-arabinose-, L-arabinose-, D-galactose-, D-glucose- and D-mannose- S-methyl- and S-benzylhydrazonecarbodithioates were synthesized and characterized by elemental analyses, infrared and UV-Vis. In these complexes the aldehydo sugar hydrazone acts as a mononegative NS bidentate ligand. The reaction of Cu(II) chloride, however, proceeded with reduction, and copper(I) complexes were isolated. The hydrazone molecule in these Cu(I) complexes acts as neutral NS bidentate ligand. Dehydro-L-ascorbic acid bis(S-methylhydrazinecarbodithioate) and bis(hydrazinecarbothioamide), as well as their corresponding Cu(II), Ni(II), zinc(II) and Pd(II) complexes were prepared and characterized. Electrospray (ES) and field desorption (FD) mass spectra suggest that the Cu(II), Ni(II), and Pd(II) complexes are monomeric (square planar), whereas the Zn(II) are dimeric and pentacoordinate.

Aldehydes↗
PubMed2002

Synthesis, characterization and evaluation of antituberculosis activity of some hydrazones.

Several new hydrazone derivatives were prepared by the reaction of some active hydrogen compounds with the diazonium salts of 4-amino-3,5-di/1,3,5-trimethylpyrazoles at 0-5 degrees C. Structures of the new substances were confirmed using UV, IR, 1H NMR, 13C NMR and EI-mass spectral data. In vitro antituberculosis activity of these compounds were tested on Mycobacterium tuberculosis H37Rv at 6.25 microg/ml. Both hydrazone products, ethyl 2-[(3,5-dimethylpyrazole-4-yl)hydrazono]-3-oxobutyrate (3d) and methyl 2-[(3,5-dimethylpyrazole-4-yl)hydrazono]4-methoxy-3-oxobutyrate (3e) showed 29 and 28% inhibition against M. tuberculosis, respectively.

Acetoacetates↗
PubMedDate not supplied

New hydrazone derivatives of adriamycin and their immunoconjugates--a correlation between acid stability and cytotoxicity.

New N-substituted hydrazine linkers were synthesized and their hydrazone derivatives of adriamycin were prepared. These functionalized adriamycin derivatives were conjugated with a monoclonal antibody, 5E9. The release rate of adriamycin from the hydrazones and from some of the conjugates was studied, and their relationship to the IC50's of the conjugate against 5E9-positive Daudi cells was investigated.

Antibodies, Monoclonal↗
PubMed1990

A new mechanism-based inhibitor of photosynthetic water oxidation: acetone hydrazone. 1. Equilibrium reactions.

The process of photosynthetic water oxidation has been investigated by using a new type of water oxidation inhibitor, the alkyl hydrazones. Acetone hydrazone (AceH), (CH3)2CNNH2, inhibits water oxidation by a mechanism that is analogous to that of NH2OH. This involves binding to the water-oxidizing complex (WOC), followed by photoreversible reduction of manganese (loss of the S1----S2 reaction). At higher AceH concentrations the S1 state is reduced in the dark and Mn is released, albeit to a lesser extent than with NH2OH. Following extraction of Mn, AceH is able to donate electrons rapidly to the reaction center tyrosine radical Z+ (161Tyr-D1 protein), more slowly to a reaction center radical C+, and not at all to the dark-stable tyrosine radical D+ (160Tyr-D2 protein) which must be sequestered in an inaccessible site. Manganese, Z+, and C+ thus appear to be located in a common protein domain, with Mn being the first accessible donor, followed by Z+ and then C+. Photooxidation of Cyt b-559 is suppressed by AceH, indicating either reduction or competition for donation to P680+. Unexpectedly, Cl- was found not to interfere or compete with AceH for binding to the WOC in the S1 state, in contrast to the reported rate of binding of N,N-dimethylhydroxylamine, (CH3)2NOH [Beck, W., & Brudvig, G. (1988) J. Am. Chem. Soc. 110, 1517-1523]. We interpret the latter behavior as due to ionic screening of the thylakoid membrane, rather than a specific Cl- site involved in water oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetone↗
PubMed1980

Long-acting opiate agonists and antagonists: 14-hydroxydihydromorphinone hydrazones.

Two new long-acting hydrazone derivatives of 14-hydroxydihydromorphinones have been synthesized, oxymorphazone and naltrexazone. Both derivatives show high affinity for opiate binding sites in vitro, similar to naloxazone, the hydrazone analogue of naloxone. Sodium and manganese shifts imply that naltrexazone, like naloxazone, is a pure antagonist. By contrast, oxymorphazone inhibition of receptor binding is dramatically reduced by sodium and potentiated by manganese, suggesting it is an agonist. When given in vivo, all agents produce a significant inhibition of receptor binding for over 24 h despite extensive washing of the brain homogenates. Oxymorphone, naltrexone, and naloxone are without effect. Twenty-four hours after in vivo administration of oxymorphazone, 82% of mice are still analgetic compared to only 17% of oxymorphone-treated mice (p less than 0.005). Twenty-four hours after naltexazone or naloxazone treatment all mice were protected from morphine analgesia (12 mg/kg; p less than 0.005), while naltrexone- and naloxone-treated animals did not differ significantly from saline-treated controls.

Analgesics, Opioid↗
PubMed1985

Relationship between structure and antineoplastic activity of (arylsulfonyl)hydrazones of 4-pyridinecarboxaldehyde.

The effects of various structural modifications on the antineoplastic activity of (arylsulfonyl)hydrazones of 4-pyridinecarboxaldehyde were examined in mice bearing either Sarcoma 180 or P388 leukemia. The introduction of different functional groups into the phenyl ring of the benzenesulfonyl moiety did not alter tumor inhibitory activity appreciably, and the pyridine ring could be replaced by 4-nitrobenzene without loss of antineoplastic activity. However, the aldehyde proton and the hydrazone proton alpha to the sulfonyl group were essential, and their substitution resulted in inactive anticancer agents.

Animals↗
PubMed1988

Potential antisecretory antidiarrheals. 1. Alpha 2-adrenergic aromatic aminoguanidine hydrazones.

Guanabenz, a centrally acting antihypertensive agent, has been shown to have intestinal antisecretory properties. A series of aromatic aminoguanidine hydrazones was made in an effort to separate the antisecretory and cardiovascular activities. Benzaldehyde, naphthaldehyde, and tetralone derivatives were synthesized. The compounds were evaluated in the cholera toxin treated ligated jejunum of the rat and in the Ussing chamber using a rabbit ileum preparation. A number of compounds, including members of each structural class, were active upon subcutaneous administration in the rat. Active compounds were determined to be alpha 2-adrenergic agonists by yohimbine reversals of their Ussing chamber activities. The compound displaying the best separation of activities was the aminoguanidine hydrazone of 2,6-dimethyl-4-hydroxybenzaldehyde (20).

Adrenergic alpha-Agonists↗