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PubMed1991

Synthesis and application of Fmoc-hydrazine for the quantitative determination of saccharides by reversed-phase high-performance liquid chromatography in the low and subpicomole range.

A new derivatization reagent, Fmoc-hydrazine, has been synthesized from the reaction of Fmoc-chloroformate with hydrazine as a precolumn fluorometric labeling reagent for reducing sugars such as glucose, galactose, mannose, fructose, fucose, ribose, xylose, arabinose, lactose, and maltose. The optimization of derivatization conditions was examined in detail. Using a reversed-phase high-performance C-8 column and a mobile phase consisting of acetonitrile-aqueous acetic acid, seven sugar derivatives were separated under either isocratic or gradient conditions within 20 min. The Fmoc-hydrazine and sugar Fmoc-hydrazone derivatives exhibit excellent stability. The extent of the hydrazone formation was 77 and 82% for mannose and fucose as assessed by Dionex high-performance anion-exchange chromatography with pulsed amperometric detection. Linear calibration graphs were established in the range from 0.5 to 2 pmol and 12 to 110 pmol for individual sugar derivatives. The determination limits were 0.05-0.09 pmol for mannose, galactose, and ribose; 0.1 pmol for maltose, xylose, and glucose; 0.2 pmol for fucose and lactose; 0.3 pmol for arabinose; and 0.4 pmol for fructose. The component monosaccharides of ultramicroquantities of two glycoproteins (e.g., from 7 ng fetuin and ovalbumin) were determined in the subpicomole range.

Acetates↗
PubMed1993

Taurine protects against the cytotoxicity of hydrazine, 1,4-naphthoquinone and carbon tetrachloride in isolated rat hepatocytes.

Exposure of rat hepatocytes to hydrazine, carbon tetrachloride or 1,4-naphthoquinone results in cytotoxicity determined as uptake of Trypan blue and leakage of lactate dehydrogenase (LDH). After exposure of hepatocytes to hydrazine and 1,4-naphthoquinone, ATP was also measured and was found to be depleted. Addition of the beta-amino acid taurine to the hepatocyte incubation buffer partially protects the cells against the cytotoxicity of these three different cytotoxic compounds, as indicated by Trypan blue uptake and LDH leakage. Taurine also reduces the depletion of ATP caused by 1,4-naphthoquinone but not hydrazine. It is suggested that taurine may have a cytoprotective effect in vitro and may be a useful tool for the investigation of mechanisms of cytotoxicity.

Animals↗
PubMed1983

Changes induced by hydrazine in optical spectra of cytochrome oxidase.

Under aerobic conditions hydrazine reduces haem a of cardiac cytochrome oxidase and brings about the formation in optical spectra of a new band at 845 nm, whereas under anaerobic conditions hydrazine reduces both haems, a and a3, as well as EPR-detectable copper, CuA, and results in the band at 845 nm. The formation of this band was sensitive to inhibitors of oxygen binding. It is suggested that the band at 845 nm reflects changes induced by hydrazine in CuB which in the resting enzyme is EPR-undetectable.

Animals↗
PubMed1984

Mutagenicity and carcinogenicity of mono- and diacetyl hydrazine.

Two hydrazine derivatives, monoacetyl hydrazine (MAH) and diacetyl hydrazine (DAH), have been tested for mutagenic response in the Salmonella/mammalian microsome assay and micronucleus test. MAH but not DAH, increased the revertant mutants in TA100 and TA1535 and also increased the frequency of micronuclei in polychromatic erythrocytes. Gavage administration of MAH but not of DAH, resulted in increased incidence of lung tumors. These observations record for the first time the mutagenicity/carcinogenicity of MAH which is one of the metabolites of isoniazid in animals and humans.

Adenocarcinoma, Papillary↗
PubMed1987

Activation of hydrazine derivatives to free radicals in the perfused rat liver: a spin-trapping study.

Spin-trapping techniques and electron spin resonance spectroscopy have been used to study bioactivations of hydrazine and its derivatives by isolated perfused rat livers. Using phenylbutylnitrone (PBN) as the stable spin trap, it was found that the liver perfusion of hydrazine, acetylhydrazine and isoniazid resulted in the formation of the same carbon-centered radical which was shown to be the acetyl radical. The identity of the acetyl radical was confirmed after organic extraction of the liver perfusates, by comparing its coupling constants with those of the in vitro metal ion- or horseradish peroxidase-catalyzed oxidation products of the hydrazines in the same solvents. The liver perfusion of iproniazid formed the isopropyl radical which was previously observed to result from peroxidase-catalyzed oxidation.

Animals↗
PubMed1983

In vitro screening of the effect of hydrazine derivatives on hepatic aryl hydrocarbon hydroxylase activity.

1. The effect of hydrazine derivatives on the in vitro hepatic microsomal aryl hydrocarbon hydroxylase activity was examined using Sprague-Dawley male rats. 2. All hydrazine derivatives examined have some degree of inhibition on hepatic aryl hydrocarbon hydroxylase activity. 3. The inhibitory effect is concentration dependent and is also dependent on the structural substitution of the hydrazines. The more lipophilic the derivative, the more potent the inhibition of aryl hydrocarbon hydroxylase activity.

Animals↗
PubMed1993

Determination of hydrazine in human plasma by high-performance liquid chromatography.

A simple and sensitive liquid chromatographic method for the determination of hydrazine in human plasma and serum is described. Samples were prepared in a single-step reaction by protein denaturation with trichloroacetic acid and derivatization to a stable azine with 4-hydroxybenzaldehyde. Chromatographic separation was carried out on a reversed-phase (octadecylsilane) column with methanol-water (60:40) as mobile phase and ultraviolet detection at 340 nm. Linearity was found in the range 5-1000 ng/ml. The detection limit of spiked plasma was 1 ng/ml. The coefficient of variation ranged from 1.7 to 3.8%. No degradation of hydrazine was found in spiked plasma and serum, even after storage at room temperature for one week. An increased hydrazine level was found after in vitro degradation from isoniazid in human serum.

Chromatography, High Pressure Liquid↗
PubMed2005

Reduction of Cr(VI) by hydrazine in solution saturated with KHCO3.

Cr(VI) that exists in many industrial wastes is considered highly toxic. One of the most common ways to dispose of these wastes is to reduce Cr(VI) to Cr(III), which is less toxic and can be easily removed or fixed. Reduction of Cr(VI) by hydrazine in aqueous solutions saturated with potassium bicarbonate was studied in this paper. The content of Cr(VI), molar ratio of hydrazine to Cr(VI) and reaction temperature were 200-1000 ppm, 2:1-10:1 and 25-70 degrees C, respectively. Results showed that the overall reaction was third-order, i.e. first-order with respect to hydrazine and second-order with respect to Cr(VI). The apparent empirical activation energy was 75.6 kJmol(-1). The reaction kinetics could be interpreted by a three-step mechanism. Effect of the oxygen in the solution on the reduction of Cr(VI) was negligible.

Bicarbonates↗
PubMed2006

N-2-hydroxy-4-methoxyacetophenone-N'-4-nitrobenzoyl hydrazine: synthesis and structural characterization.

A new aroyl hydrazone, N-2-hydroxy-4-methoxyacetophenone-N'-4-nitrobenzoyl hydrazine was prepared by the condensation reaction of 2-hydroxy-4-methoxyacetophenone and 4-nitrobenzoyl hydrazine. Characterization of the compound was done by elemental analysis and electronic, infrared and NMR spectral analyses. The complete structural assignment of the compound was done by NMR studies by using COSY homonuclear and HSQC heteronuclear techniques. The crystal and molecular structure was determined by single crystal X-ray diffraction studies: crystallized in the monoclinic system, space group P2(1)/n, Z=4, a=7.3343(9)A, b=20.3517(9)A, c=10.1375(5)A, alpha=90.00 degrees, beta=95.735(7) degrees and gamma=90.00 degrees. From the crystal structure, it is concluded that the compound exists as the keto isomer in the solid state. There is a completely extended conformation in the central part of the molecule C5C8N1N2C10O2 with an E configuration at the double bond of the hydrazinic bridge.

Acetophenones↗
PubMed1997

Involvement of polyamines in the protection of taurine against the cytotoxicity of hydrazine or carbon tetrachloride in isolated rat hepatocytes.

Taurine (2-aminoethanesulfonic acid) is known to protect hepatocyte injury induced by hydrazine or carbon tetrachloride. We investigated whether cellular polyamines are involved in the protective mechanism of taurine in the hepatocyte injury caused by hydrazine or carbon tetrachloride. The agents decreased cellular polyamine concentrations, but the treatment with taurine prevented this decrease. The protection of taurine against hepatic injury was not observed in hepatocytes treated with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase which is a key enzyme in polyamine biosynthesis. The protection of taurine was recovered by the addition of polyamines to DFMO-treated hepatocytes. These results suggest that cellular polyamines play an important role in the protection of taurine in hydrazine or carbon tetrachloride-induced hepatocyte injury.

Animals↗
PubMed1999

Detection of hydrazine, methylhydrazine and isoniazid by capillary electrophoresis with a 4-pyridyl hydroquinone self-assembled microdisk platinum electrode.

Capillary electrophoresis (CE)/electrochemical detection (EC) for the simultaneous detection of hydrazine, methylhydrazine, and isoniazid has been developed with a 4-pyridyl hydroquinone self-assembled microdisk platinum electrode. Such an electrode has very high catalytic ability for hydrazines and they could be detected even at 0.0 V. The responses for hydrazine, methylhydrazine, and isoniazid are linear over 3 orders of detected concentration and of magnitude of 0.2-400 microM, 0.2-400 microM, 0.5 microM-2 mM, with correlation coefficients of 0.9998, 0.9991, and 0.9982, respectively. And they could be detected to levels of 0.1, 0.1 and 0.2 microM, respectively. This modified electrode was found to be very stable and reproducible when continuously used as detector for capillary electrophoresis for period of at least 4 weeks with no apparent loss of response.

Electrochemistry↗
PubMed1999

Hydrazine cation radical in the active site of ethanolamine ammonia-lyase: mechanism-based inactivation by hydroxyethylhydrazine.

A study has been made of the mechanism of inactivation of the adenosylcobalamin-dependent enzyme, ethanolamine ammonia-lyase (EAL), by hydroxyethylhydrazine. Incubation of EAL with adenosylcobalamin and hydroxyethylhydrazine, an analogue of ethanolamine, leads to rapid and complete loss of enzymic activity. Equimolar quantities of 5'-deoxyadenosine, cob(II)alamin (B(12r)), hydrazine cation radical, and acetaldehyde are products of the inactivation. Inactivation is attributed to the tight binding of B(12r) in the active site. Removal of B(12r) from the protein by ammonium sulfate precipitation under acidic conditions, however, restores significant activity. This inactivation event has also been monitored by electron paramagnetic resonance (EPR) spectroscopy. In addition to EPR signals associated with B(12r), spectra of samples of inactivation mixtures reveal the presence of another radical. The other radical is bound in the active site where it undergoes weak magnetic interactions with the low spin Co(2+) in B(12r). The radical species was unambiguously identified as a hydrazine cation radical by using [(15)N(2)]hydroxyethylhydrazine, (2)H(2)O, and quantitative interpretation of the EPR spectra. Homolytic fragmentation of a hydroxyethylhydrazine radical to acetaldehyde and a hydrazine cation radical is consistent with all of the observations. All of the experiments indicate that the mechanism-based inactivation of EAL by hydroxyethylhydrazine results from irreversible cleavage of the cofactor and tight binding of B(12r) to the active site.

Binding Sites↗
PubMed2006

Excited-state mixed-valence distortions in a diisopropyl diphenyl hydrazine cation.

Excited-state mixed valence (ESMV) occurs in the 1,2-diphenyl-1,2-diisopropyl hydrazine radical cation, a molecule in which the ground state has a symmetrical charge distribution localized primarily on the hydrazine, but the phenyl to hydrazine charge-transfer excited state has two interchangeably equivalent phenyl groups that have different formal oxidation states. Electronic absorption and resonance Raman spectra are presented. The neighboring orbital model is employed to interpret the absorption spectrum and coupling. Resonance Raman spectroscopy is used to determine the excited-state distortions. The frequencies of the enhanced modes from the resonance Raman spectra are used together with the time-dependent theory of spectroscopy to fit the two observed absorption bands that have resolved vibronic structure. The origins of the vibronic structure and relationships with the neighboring orbital model are discussed.

Cations↗
PubMed1993

Synthesis and evaluation of 1-acyl-1,2-bis(methylsulfonyl)-2-(2- chloroethyl)hydrazines as antineoplastic agents.

A series of 1-acyl-1,2-bis(methylsulfonyl)-2-(2-chloroethyl)hydrazines, conceived as more potent analogs of 1-(2-chloroethyl)-1,2,2-tris(methylsulfonyl)hydrazine, were synthesized and evaluated for antineoplastic activity against the L1210 leukemia in mice. Of these, 1-acetyl-1,2-bis-(methylsulfonyl)-2-(2-chloroethyl)hydrazine produced "cures" of mice bearing the L1210 leukemia at dosage levels that were considerably less than those at which the tris(sulfonyl) analog produced its antineoplastic effects. This compound was also found to have pronounced activity against the P388 leukemia and against several solid tumors, including the B16F10 melanoma, the M5076 reticulum cell sarcoma, and the M109 lung carcinoma. Furthermore, the acyl derivatives were in general considerably more resistant to hydrolysis in aqueous media and more prone to protease- and thiol-mediated activation than the tris(sulfonyl) analog. The former property is important to formulation, while the latter properties may result in some degree of drug targeting and enhancement of the therapeutic indices of these agents.

Acylation↗
PubMed1985

Synthesis and evaluation of N,N'-bis(arylsulfonyl)hydrazines as antineoplastic agents.

Several N,N'-bis(arylsulfonyl)hydrazines, with the potential to function as biological methylating agents, were synthesized and evaluated for antineoplastic activity against the L1210 leukemia and other transplanted rodent tumors. In general, the N-methyl-N,N'-bis(arylsulfonyl)hydrazines that possess the capacity to generate an alkylating species under physiological conditions showed significant antineoplastic activity, while N,N'-bis(phenylsulfonyl)-hydrazine and N-methyl-N,N'-dibenzoylhydrazine were inactive.

Animals↗
PubMed2006

Facile synthesis of mono-, di-, and trisubstituted alpha-unbranched hydrazines.

Methods for the alkylation of di-tert-butyl hydrazine-1,2-dicarboxylate were investigated. It was found that under mild conditions mono- or di-substituted hydrazine derivatives were obtained in good to excellent yield. Furthermore, it was shown that one of the two Boc-groups of the disubstituted derivatives was selectively removed by heating, leading to precursors for trisubstituted hydrazines.

Hydrazines↗
PubMed2002

Intermolecular alkyne hydroaminations involving 1,1-disubstituted hydrazines.

[reaction: see text] Two readily prepared catalysts have been developed for the hydroamination of alkynes by 1,1-disubstituted hydrazines. The catalyses are facile with terminal alkynes and some internal alkynes. If the hydrazine bears an aryl group, Fischer cyclization can occur in a one-pot procedure. In addition, reactions with acetylene to produce a plethora of hydrazones are described. Catalytic reactions involving acetylene and substituted hydrazines are complete in less than 2 h at room temperature and 1 atm of pressure.

Alkynes↗
PubMed1981

Chemical modification of peptides by hydrazine.

High pressure ('performance') liquid chromatography on reverse-phase supports has been used to characterize the products arising from the hydrazine treatment of peptides. In addition to converting arginine residues into ornithine, the reaction was found to cleave predominately Gly-Xaa, Xaa-Gly, Asn-Xaa and Xaa-Ser peptide bonds. Peptide-bond cleavage and deguanidation was studied as a function of time of exposure to hydrazine, hydrazine concentration and temperature. The convenience of this method of chromatography for the rapid low-cost separation and isolation of peptides, as well as their reaction products, is illustrated at the level of material required for solid-phase microsequencing.

Amino Acids↗