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PubMed1994

The reaction of methylglyoxal with aminoguanidine under physiological conditions and prevention of methylglyoxal binding to plasma proteins.

Increased formation of methylglyoxal in clinical diabetes mellitus and metabolism by the glyoxalase system has been linked to the development of clinical complications of diabetes: retinopathy, neuropathy and nephropathy. Aminoguanidine has been proposed as a prophylactic agent for preventive therapy of diabetic complications. Methylglyoxal reacted with aminoguanidine under physiological conditions to form two isomeric triazines, 3-amino-5-methyl-1,2,4-triazine and 3-amino-6-methyl-1,2,4-triazine. The mean second order rate constant for the reaction of methylglyoxal with aminoguanidine, kMG.AG = 0.39 +/- 0.06 M-1 sec-1 at pH 7.4 and 37 degrees. Under these conditions, no methylglyoxal bisguanylhydrazone was detected. Aminoguanidine prevented the irreversible modification of human plasma protein by a physiological concentration of methylglyoxal (1 microM); the median inhibitory concentration IC50 value of aminoguanidine was 203 +/- 16 microM (N = 28). The scavenging of methylglyoxal by aminoguanidine may contribute to the beneficial effects of aminoguanidine in the prevention of vascular pathogenesis in diabetes.

Blood Proteins↗
PubMed1995

Trace determination of herbicides in estuarine waters by liquid chromatography-high-flow pneumatically assisted electrospray mass spectrometry.

High-flow pneumatically assisted electrospray (ESP) was applied to the characterization of triazine (atrazine, simazine, ametryne, cyanazine, deethylatrazine and deisopropylatrazine), phenylurea (chlortoluron++, isoproturon, diuron, linuron and diflubenzuron) and other priority herbicides (alachlor, metolachlor). In LC-ESP-MS the [M+Na]+ ion was used as the base peak in most cases, with the exception of chlorotriazines, which showed [M+H]+ as the base peak. When LC-TSP-MS was used, [M+H]+ was the base peak for many of the pesticides, with the exception of linuron and diflubenzuron, which showed [M+NH4]+ as the base peak. The ESP results were compared with those obtained with thermospray (TSP). LC-TSP-MS offered greater sensitivity for triazines than phenylurea herbicides, whereas the use of LC-ESP-MS offered an enhancement in sensitivity for phenylurea herbicides. As regards the fragmentation obtained using both techniques, ESP offered a considerable amount of structural information for the different chlorotriazines studied when the extraction voltage was increased from 20 to 40 V. Liquid-liquid extraction with dichloromethane was used for the trace enrichment of the different herbicides in estaurine water samples from the Elorn river (France). The presence of the different triazine metabolites, atrazine, simazine, metolachlor, isoproturon and diuron was confirmed by both LC-MS techniques.

Chromatography, High Pressure Liquid↗
PubMed1988

On the mutagenic and recombinogenic activity of certain herbicides in Salmonella typhimurium and in Aspergillus nidulans.

The plant growth-regulating hormones indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA), both strong recombinogens in Aspergillus nidulans, were tested in Salmonella typhimurium strains for his revertants at a range of concentrations from 1 to 2000 micrograms/plate with and without metabolic activation and were found negative. Also 3 herbicides of the chlorophenoxy group, 2,4-(dichlorophenoxy)acetic acid (2,4-D), 2,4-(dichlorophenoxy)butyric acid (2,4-DB) and 4-chloro-2-methylphenoxyacetic acid (MCPA), which show a plant growth hormone-like activity, and 2 of the triazine group, 2-ethylamino-4-chloro-6-isopropylamino-1,3,5-triazine (atrazine) and 2,4-bis(isopropylamino)6-chloro-1,3,5-triazine (propazine) were tested in S. typhimurium for point mutations and in A. nidulans for mitotic recombination. 2,4-D and MCPA were found to be weakly mutagenic at concentrations between 250 and 750 micrograms/plate in strain TA97a and only after metabolic activation and were recombinogens by inducing mainly mitotic crossing-over in A. nidulans at concentrations of 4-48 microM and 1500-3000 microM, respectively. 2,4-DB, atrazine and propazine were negative in both the Ames and the Aspergillus tests.

Animals↗
PubMed1990

Determination of the effect of tridiphane on the pharmacokinetics of [14C]-atrazine following oral administration to male Fischer 344 rats.

The absorption, distribution, metabolism and excretion of [14C]-atrazine was studied in male Fischer 344 rats administered a 30 mg [14C]-atrazine/kg of body weight oral dose with or without pretreatment with a non-radiolabeled oral dose of 60 mg tridiphane/kg of body weight. The objective of this study was to determine whether tridiphane had any meaningful effect on the pharmacokinetics and/or metabolism of atrazine in the rat. The 14C plasma time-course exhibited a mono-exponential decrease with an absorption and elimination half-life of approximately 3 h and 11 h, respectively for both treatment groups. In addition, at 72 h after the administration of [14C]-atrazine, approximately 93% of the administered radioactivity was recovered and the primary route of excretion was via the urine (67%) for both treatment groups. The feces accounted for approximately 18% of the dose, and less than 10% remained in the carcass, skin, and red blood cells (RBCs). The urine excreted in the first 24 h post-dosing contained approximately 57% of the administered radioactivity for both treatment groups. There were no appreciable differences in the metabolite distribution between treatment groups, and the major urinary metabolite of atrazine was found to be 2-chloro-4,6-diamino-1,3,5-triazine (II; 64-67%). Additionally, S-(2-amino-4-methylethylamino-1,3,5-triazin-6-yl)-mercapturi c acid (V; 13-14%), and S-(2,4-diamino-1,3,5-triazin-6-yl)-mercapturic acid (III; 9%) were tentatively identified based upon similar HPLC retention times as seen with synthesized standards. These data indicate that there are no meaningful differences in the absorption, distribution, metabolism, and excretion between rats administered only [14C]-atrazine and those administered both tridiphane and [14C]-atrazine. Therefore, it can be concluded that tridiphane has no meaningful effect on the pharmacokinetics and/or metabolism of atrazine in the rat.

Administration, Oral↗
PubMed2005

Sol-gel-coated oligomers as novel stationary phases for solid-phase microextraction.

Amphiphilic and hydrophilic oligomers were synthesized and coated on fused silica capillaries using a sol-gel technique. Sol-gel-coated capillaries were evaluated for the solid-phase microextraction and preconcentration of a wide variety of non-polar and polar analytes. Both types of coatings were stable under high temperature (up to 280 degrees C). The extraction efficiency of the sol-gel coatings was evaluated for the extraction of both non-polar and polar analytes, including organochlorine pesticides, triazine herbicides, estrogens and alkylphenols (APs) and bisphenol-A (BPA). Compared with commercially available solid-phase microextraction (SPME) adsorbents such as poly(dimethylsiloxane)divenylbenzene and polyacrylate, the new materials showed comparable selectivity and sensitivity towards both non-polar and polar analytes. The new coatings gave good linearity and detection limits. For example with triazines, a detection limit of <0.005 microl l(-1), precision from 5.0 to 11.0% (n = 6) and linearity of the calibration plots (0.5 to 50 microl l(-1)) were obtained. The sol-gel coated SPME capillaries were used for the determination of triazine herbicides in reservoir water samples collected in Singapore.

Estrogens↗
PubMed2005

Use of immobilized cytochrome c as a ligand for affinity chromatography of thiosulfate dehydrogenase from Acidithiobacillus ferrooxidans.

Three matrices were used for immobilizing the cytochrome c: Sepharose CL-4B, Silasorb SPH amine and a laboratory-prepared new matrix based on crosslinked triazine (2,4,6-tris(aminoethylamine)-1,3,5-triazine) (TAT). Cytochrome c was immobilized on the matrices by several procedures and the amount of incorporated cytochrome c was determined. Cytochrome c immobilized on Sepharose CL-4B with periodate activation, cytochrome c immobilized on Silasorb-amine with carbodiimide activation and cytochrome c immobilized on crosslinked triazine were suitable for purification of thiosulfate dehydrogenase from Acidithiobacillus ferrooxidans. The yield with all matrices was about 90%. The purification factor of the above matrices was about 15. A new matrix based on TAT with cytochrome c represented a suitable way for thiosulfate dehydrogenase purification.

Acidithiobacillus↗
PubMed2006

Emerging antifungal azoles and effects on Magnaporthe grisea.

Derivatives of pyrazolo[1,5-a][1, 3, 5]triazine-2,4-dione,pyrazolo[1,5-c][1, 3, 5]thiadiazine-2-one, pyrazolo[3,4-d][1, 3]thiazine-4-one, and pyrazolo[3,4-d][1, 3]thiazine-4-thione were screened for antifungal activity against the causal agent of rice blast disease, Magnaporthe grisea. The compounds were tested at doses ranging from 10 to 200mugml(-1), using the commercial fungicide tricyclazole as reference compound. All triazine derivatives inhibited the growth and pigmentation of the mycelia less effectively than tricyclazole. The thiadiazine derivatives proved to be more effective than their triazine counterparts, but only 4-(butylimino)-7-methylpyrazolo[1,5-c][1,3,5]thiadiazine-2-one (2h) and 4-(cyclohexylimino)-7-methylpyrazolo[1,5-c][1,3,5]thiadiazine-2-one (2j) were more effective than tricyclazole. Pyrazolo[3,4-d][1,3]thiazine-4-one derivatives were active only at the highest doses, whereas members of the pyrazolo[3,4-d][1,3]thiazine-4-thione series inhibited fungal growth at the lowest concentrations used, at which tricyclazole had no effect. A dose-dependent mechanism might be responsible for this effect, with lipophilicity as the governing factor. Within a given set, the presence of a cyclohexyl or an n-butyl group generally increased antifungal activity, with respect to both growth inhibition and cell de-pigmentation of the mycelium, suggesting that a higher lipophilicity might improve transport inside the cells. SEM and TEM of M. grisea hyphae showed that treatment with the most active substance (2h) caused significant ultrastructural effects, particularly on the endomembrane system, suggesting a mechanism of action similar to that of most azole fungicides. Dissimilarities were also observed, with no alterations of the cell wall evident. In conclusion, several compounds showed greater inhibition than tricyclazole, and therefore provide useful new chemistry for control of M. grisea infections.

Antifungal Agents↗
PubMed1983

Preparative high-performance liquid affinity chromatography.

The reactive triazine dye, Procion Blue MX-R, has been covalently attached to preparative-grade silica and used for the large-scale purification of rabbit muscle lactate dehydrogenase by high-performance liquid affinity chromatography (HPLAC). Purified dye was coupled directly to glycol-silylated silica via the reactive triazine ring to yield an adsorbent containing 12 mumol dye/g silica. Essentially homogeneous lactate dehydrogenase in 80% overall yield was obtained from crude extracts. Thus this report demonstrates the potential for adapting the speed of operation and resolution shown for triazine dye-HPLAC in analytical applications to preparative protein purification.

Animals↗
PubMed1999

Atmospheric pressure ionisation multiple mass spectrometric analysis of pesticides.

Liquid chromatography-multiple mass spectrometry (LC-MS") has been investigated for analysis of polar pesticides in water using an ion-trap instrument and atmospheric pressure ionisation. Carbamate, triazine and phenylurea pesticides were best ionised as positive ions with atmospheric pressure chemical ionisation, while phenoxy acid herbicides, nitrophenols and bentazone yielded stronger signals as negative ions with pneumatically assisted electrospray. The ion fragmentation processes and pathways were studied in detail by MS, MS2, MS3 and MS4. All compounds were observed as their protonised or deprotonised molecular ions by MS and in the successive fragmentation by MS" the structures of typical (diagnostic) product ions were tentatively identified for each class of pesticide. Phenylureas yield an ion at m/z 72 by MS2, corresponding to O=C=N+(CH3)2. Carbamates produce [M+H-CONCH3]+ fragments by MS2 from neutral loss of methylisocyanate. Characteristic fragmentation pathways for triazine pesticides are [M+H]+-->m/z 174-->m/z 146-->m/z 110 and [M+H]+-->m/z 174-->m/z 132-->m/z 104 by MS-MS2-MS3-MS4 from cleavage of lateral chains in the triazine ring followed by ring opening. Phenoxy acid herbicides produce peculiar fragments by MS2 from loss of the acidic group possibly as the corresponding lactone. Nitrophenols are subject to loss of both *OH radical and NO groups thereby forming the correspondent phenols and quinones. The performance of the method with respect to quantitation compares favourably with traditional methods. With the ion-trap run in a time scheduled single ion monitoring mode, typical limits of detection (LODs) are in the low pg range and the repeatability standard deviations are between 3 and 15%. Assuming extraction of 1-l water samples and 1 ml final volumes the injection of 50-microl aliquots corresponds to LODs well below the requirement for the European Union water directive (EC/80/778).

Atmospheric Pressure↗
PubMed2002

One- and two-dimensional silver-coordination networks containing pi-sandwiched silver-silver interactions.

The self-assembly of coordination networks from reaction of 2,4,6-trimesityl-1,3,5-triazine and silver(I) trifluoroacetate is described. A one-dimensional linear polymer is formed from solutions deficient in silver while a two-dimensional, graphite-like sheet is formed from solutions containing 3 equiv of silver per triazine. The structurally similar networks both contain triazine rings separated by two trifluoroacetate-bridged silver atoms. The two silver atoms are effectively sandwiched between two mesityl rings with intermediate arene-silver interactions. The silver-silver bond lengths are 2.9731(4) and 2.9246(5) A in the one-dimensional network and 2.8842(4) A in the two-dimensional network.

Journal Article↗
PubMed2001

Orthogonal, convergent syntheses of dendrimers based on melamine with one or two unique surface sites for manipulation.

An orthogonal, convergent route for the introduction of substoichiometric numbers of latent surface sites into dendrimers based on melamine is used to prepare targets that display one or two Boc-protected amines on the periphery. Asymmetry is the result of the stepwise incorporation of functionalized and unfunctionalized dendrons onto the triazine cores, a highly selective process due to the different reactivities of the substituted triazines. The routes to the dendrons rely on iterative reactions of the growing dendrons with triazine cores and diamine linkers. p-Aminobenzylamine is used as a linking group to avoid functional group interconversions or protecting group manipulations. Addition of the benzylamine group to the monochlorotriazine of the dendron proceeds cleanly leaving a less reactive aniline for subsequent reaction with trichlorotriazine. The routes to these targets proceed in 5 or 6 linear steps (11 or 12 total steps) in 40% overall yield. The unique surface sites can be deprotected and subjected to additional chemistries. Reaction of the monofunctionalized dendrimer with trichlorotriazine yields the desired dimer, a molecule whose increased size is evident from light scattering and tapping mode atomic force microscopy, and corroborated with computation.

Journal Article↗
PubMed2001

High-pressure bulk synthesis of crystalline C(6)N(9)H(3).HCl: a novel c(3)n(4) graphitic derivative.

A novel carbon nitride compound, structurally related to the proposed graphitic phase of C(3)N(4), has been synthesized in a bulk well-crystallized form. The new material, with stoichiometry C(6)N(9)H(4)Cl, was prepared through a solid-state reaction of 2,4,6-triamino-1,3,5-triazine with 2,4,6-trichloro-1,3,5-triazine at 1.0-1.5 GPa and 500-550 degrees C and also through a self-reaction of 2-amino-4,6-dichloro-1,3,5-triazine at similar conditions. X-ray and electron diffraction measurements on the yellowish compound indicate a hexagonal space group (P6(3)/m) with cell parameters of a = 8.4379(10) A and c = 6.4296(2) A. This new compound possesses a two-dimensional C(6)N(9)H(3) framework that is structurally related to the hypothetical P6m2 graphitic phase of C(3)N(4), but with an ordered arrangement of C(3)N(3) voids. The large voids in the graphene sheets are occupied by chloride ions with an equivalent number of nitrogen atoms on the framework protonated for charge balance. The composition of the sample was determined by bulk chemical analysis and confirmed by electron energy loss (EELS) spectroscopy. The chemical and structural model is consistent with bulk density measurements and with the infrared and (13)C NMR spectra. This work represents the first bulk synthesis of a well-characterized and highly crystalline material containing a continuous network of alternating carbon and nitrogen atoms.

Journal Article↗
PubMed2002

Anion-aromatic bonding: a case for anion recognition by pi-acidic rings.

The basis for unprecedented noncovalent bonding between anions and the aryl centroid of electron-deficient aromatic rings has been demonstrated by an ab initio study of the interaction between 1,3,5-triazine and the fluoride, chloride, and azide ion at the MP2 level of theory. Minima are also located corresponding to C[bond]H...X(-) hydrogen bonding, reactive complexes for nucleophilic attack on the triazine ring, and pi-stacking interactions (with azide). Trifluoro-1,3,5-triazine also participates in aryl centroid complexation and forms nucleophilic reactive complexes with anions. This novel mode of bonding suggests the development of new cyclophane-type receptors for the recognition of anions.

Journal Article↗
PubMed1998

Atrazine, Deethylatrazine, and Deisopropylatrazine Persistence Measured in Groundwater in Situ under Low-Oxygen Conditions.

The degradation of atrazine [2-chloro-4-(ethylamino)-6-isopropylamino-1,3,5-triazine], deethylatrazine [DEA; 2-amino-4-chloro-6-(isopropylamino)-1,3,5-triazine], and deisopropylatrazine [DIA; 2-amino-4-chloro-6-(ethylamino)-1,3,5-triazine] was assessed under limited oxygen conditions using in situ microcosms. Denitrification was induced in a shallow sand and gravel aquifer to measure the potential for degradation of atrazine, DEA, and DIA under low-O(2) conditions. The dissolved oxygen content decreased from 7-8 mg/L to </=1 mg/L within 4 days and remained less, similar3 mg/L for the remainder of the 45-day experiment. Atrazine, DEA, and DIA concentrations (normalized to the bromide concentration at each sampling time to account for dilution) did not show a significant decrease with time, indicating that these compounds are relatively stable under the low-O(2) conditions induced in the aquifer. Although removal of one alkyl group has been proposed as the rate-limiting step in atrazine degradation, no transformation of either monodealkylated metabolite (DEA or DIA) was observed in this study.

Journal Article↗
PubMed1997

Glycolonitrile oligomerization: structure of isolated oxazolines, potential heterocycles on the early earth.

A study of glycolonitrile polymerization has led to the isolation and characterization of two 2,5-dihydro-4-aminooxazoles, 4 and 5. Previous reports have misassigned these structures as s-triazines or pyrimidines. X-ray diffraction analysis of crystals of 4 and an acetylated oxazole derivative of 5 (6) confirm the proposed structures. Ab initio computations are used to assess the relative thermodynamic stability of three trimer isomers (an s-triazine, an aminohydroxypyrimidine, and an aminooxazoline), and the results indicate that 4 is a novel kinetic product. Mechanistic considerations rationalize kinetic oxazole formation over the more customary triazine or pyrimidine trimers.

Acetonitriles↗
PubMed2003

Characterization of the alterations of the chlorophyll a fluorescence induction curve after addition of Photosystem II inhibiting herbicides.

The effects of Photosystem II inhibiting herbicides, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), atrazine and two novel 2-benzylamino-1,3,5-triazine compounds, on photosynthetic oxygen evolution and chlorophyll a fluorescence induction were measured in thylakoids isolated from Chenopodium album (wild type and atrazine-resistant plants) and cyanobacterial intact cells. The resistant plants have a mutation of serine for glycine at position 264 of the D1 protein. Diuron and two members of a novel class of 2-benzylamino-1,3,5-triazine compounds were almost as active in wild-type as in atrazine-resistant thylakoids, indicating that the benzylamino substitution in the novel triazines may be important for the lack of resistance in these atrazine-resistant plants. The inhibition by the herbicides of oxygen evolution in the cyanobacteria was somewhat lower than in the thylakoids of Chenopodium album wild type, probably caused by a slower uptake in the intact cells. The so-called OJIP fluorescence induction curve was measured during a one second light pulse in the absence and in the presence of high concentrations of the four herbicides. In the presence of a herbicide we observed an increase of the initial fluorescence at the origin (Fo'), a higher J level, and a decreased steady state at its P level (Fp). The increase to Fo' and the decreased leveling Fp are discussed. After dark adaptation about 25% of the reaction centers are in the S(0) state of the oxygen evolving complex with an electron on the secondary electron accepting quinone, Q(B). The addition of a herbicide causes a transfer of the electron on Q(B) to the primary quinone acceptor, Q(A), and displacement of Q(B) by the herbicide; the reduced Q(A) leads to a higher Fo'. The decrease of Fp in the presence of the herbicides is suggested to be caused by inhibition of the photo-electrochemical stimulation of the fluorescence yield.

Journal Article↗
PubMed1997

Evaluation of atrazine positive and false positive immunoassay detections in ground water.

False positive responses on an atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine) immunoassay kit were investigated to explain possible causes for these occurrences. Ground water samples were evaluated with the immunoassay kit and positive responses (> 0.20 microgram L-1) were confirmed using gas chromatography/mass spectrometry (GC/MS). Non-confirming samples (false positives) were analyzed for seven additional compounds on GC. Resulting GC/MS and GC analyses showed that 70% of the false positives could be attributed to two compounds. Prometon (6-methoxy-N,N'-bis(1-methylethyl)-1,3,5-triazine-2,4-diamine) was responsible for the majority (64%) of the false positive responses The atrazine metabolite, deethylatrazine (2-chloro-4-amino-6-isopropylamino-1,3,5-triazine), was responsible for the other 6% of the false positives measured. Unattributed false positives (30%) were probably due to an overestimation of pesticide concentrations in the kit's lower detection range.

Atrazine↗
PubMed1998

Atrazine, alachlor, and total inorganic nitrogen concentrations of winter wind-eroded sediment samples.

The objective of this study was to determine if atrazine (2-chloro-4-ethylamino-6-isopropyl-1,3,5-triazine), alachlor [2-chloro-N-(2,6-diethylphenyl-N-(methoxymethyl)acetamide], or inorganic nitrogen was present on wind-eroded sediments collected from road ditch areas in mid to late winter. Sediment samples that had been deposited in ditches on top of snow were collected during the winters of 1994, 1995, and 1996 at randomly selected sites in eastern South Dakota and western Minnesota. Atrazine, atrazine metabolites [deethylatrazine (DEA)(6-chloro-N-1-methylethyl-1,3,5-triazine-2,4-diamine], and deisopropylatrazine (DIA) (6-chloro-N-ethyl-1,3,5-triazine-2,4-diamine), and alachlor were determined by gas chromatography. Total inorganic N (NO(3-) + NH4+) concentration was determined with a nitrogen analyzer. In all years, atrazine was detected in at least 72% of the samples, with a mean concentration of 8.9 ug kg-1 and, while DEA was detected in at least 18% of the samples. Alachlor was detected in at least 27% of the soil samples for all three years with mean sediment concentration of > 5 ug kg-1. Inorganic N concentration of all samples averaged 33 mg kg-1. These data suggest that deposition of wind-eroded sediment contributes to nonpoint source contamination of nontarget areas by agrichemicals.

Acetamides↗