New non-symmetric azido-diacetylenic s-triazine monomer for polycycloaddition

An original synthesis of a new non-symmetric energetic ABB' type monomer, 2-azido-4-propargylamino-6- propargyloxy-s-triazine, with a total yield of 40% involves the sequential introduction of propargylamino, propargyloxy and azido groups into s-triazine. DFT investigation of azide- Cl alkyne cycloaddition mechanism at M06-2X/6-311++G(d,p) level of theory for this monomer predicts that the regioselectivity of polycycloaddition reaction should increase with the number of propargylamino groups in the monomer structure due to the stabilization of the transition state, leading to 1,5-triazole regioisomer.     

Derivatives Of ditraizinylamine and tritriazinylamine

2-Arylamino-4,6-dichloro-s-triazine reacts with cyanuric chloride in the presence of alkali to yield N,N-bis(4,6-dichloro-s-triazin-2-yl)-arylamine. In like manner, 2-substituted o-chloro-, p-chloro-, o-nitro- and p-carbomethoxyphenylamino-4,6-dimethoxy-s-triazines react with cyanuric chloride to yield the corresponding 4,6-dichloro-s-triazin-2-yl-4′,6′-dimethoxy-s-triazin-2′-ylaryl-amine, while anilino-, p-toluidino, o- and p-methoxyphenylamino and o-carbomethoxyphenylamino derivatives did not. The reaction of cyanuric chloride with 2,4-dichloro-6-ethylamino-s-triazine in the presence of alkali yields the condensation product of the ditriazinylamine type and the reaction of cyanuric chloride with ammonia yields N,N-bis(4,6-dichloro-s-triazin-2-yl)- or tris(4,6-dichloro-s-triazin-2-yl)amine.     

An anomalous broad emission of s-triazine vapor

When excited into rovibronic levels of 6¹ or 6² in S₁, s-triazine vapor exhibits an emission with a broad spectral feature besides the     

Synthesis,purification and spectroscopic characterization of potential impurities of hexamethylmelamine

The syntheses and spectroscopic properties (ir, ¹H nmr, ¹³C nmr, uv and ms) of pure samples of 2-chloro-4,6-bis(dimethylamino)-s-triazine 1 , 4,6-dichloro-2-dimethylamino-s-triazine 2 , 4,6-bis(dimethylamino)-s-triazin-2(lH)-one 3 , 4-chloro-6-dimethylamino-s-triazin-2(1H)-one 4 , 6-dimethylamino-s-triazine-2,4(1H,3H)-dione 5 , and 2,4,6-tris(dimethylamino)-s-triazine (altretamine, HMM) are reported. Evidence for enol-keto equilibria are also presented for 3 , in which the enol form exhibits as an H-bonded dimer structure similar to the dimer of organic carboxylic acids.     

On the electroreduction of 4-chloro-2,6-diisopropylamino-s-triazine (propazine) on mercury electrodes

This paper presents a polarographic (dc and differential pulse (DP)) study of the reduction of the s-triazine derivative propazine (4-chloro-2,6-diisopropylamino-s-triazine). The study is performed in acidic media (from solutions 2.25 M in H₂SO₄ to pH 5) because no signals were obtained above pH 5 (even at pH values of 11–12). In the pH range 2–4 the polarograms decreased until they vanished. In DP polarography, two main reduction peaks were observed, accompanied by a pre-peak at less negative potentials, and a post-peak at more negative potentials, due to the adsorption of propazine on the electrode. The main peaks corresponded to two-electron reduction processes. At pH below the protonation pK of the triazine ring (about 1.7), the results showed that, in a first stage, propazine suffers a cleavage of the Cl atom via a CEC process (electron transfer placed between two chemical reactions) to yield a dechlorinated intermediate, which is reduced through an irreversible two-electron process, the rate-determining step (r.d.s.) being the second electron transfer. At pH above the pK, a protonation of the triazine ring precedes the reduction process, this reaction being also responsible for the observed decrease in limiting current.     

EC(EE) processes in the reduction of some 2-methylthio-4,6-di(alkylamino)-1,3,5-triazines on mercury electrodes

Polarographic (direct current, dc, and differential pulse, DP) studies of the electroreduction of the s-triazine derivatives ametryn (2-methylthio-4-ethylamino-6-isopropylamino)-1,3,5-triazine), dimethametryn (2-methylthio-4-ethylamino-6-(1,2-dimethylpropyl) amino-1,3,5-triazine) and simetryn (2-methylthio-4,6-di(ethylamino)-1,3,5-triazine) were made in the acidity range from 2.25 M H₂SO₄ to pH 6.5. Above this last pH value no signals were obtained. In DP polarography, two main reduction peaks were observed, accompanied by a pre-peak due to the adsorption of the herbicides on the electrode. The main peaks corresponded to two-electron irreversible reduction processes, at pH values higher than the protonation pK of the triazine ring (ca. 4). In this pH range, the protonation of the triazine ring preceding the reduction process is responsible for decrease in limiting current. At pH<pK the herbicides suffer a cleavage of the –SCH₃ group via two different intermediates related by a chemical reaction, whose extension depends on the herbicide.     

Determination of the antifouling booster biocides irgarol 1051 and diuron and their metabolites in seawater by high performance liquid chromatography-diode array detector

A method for the simultaneous determination of two antifouling booster biocides, diuron (1-(3,4 dichlorophenyl) 3,3 dimethyl urea) and irgarol 1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine), and their metabolites, DCPMU (1-(3,4 dichlorophenyl)-3 methyl urea), DCPU (1-(3,4 dichlorophenyl) urea), DCA (3,4 dichloroaniline) and M1 (2-methylthio-4-tert-butylamino-s-triazine) in seawater by high performance liquid chromatography-diode array detector (HPLC-DAD) was developed. The optimization of the extraction procedure included the type of sorbent and the type of the organic solvent for the elution. Optimization of the liquid chromatography (LC) separation was also performed and the robustness of the developed separation was tested, in respect to the effect of three factors (column temperature, flow rate and initial strength of acetonitrile) on the retention times, peak resolution and peak area of the six compounds. The optimized procedure included off-line extraction of these compounds from seawater samples using C18 solid phase extraction (SPE) cartridges. The inter-day precision of the developed procedure was less than 14% (as R.S.D.s) for all the tested compounds. Satisfactory recoveries (higher than 82%) were obtained for all substances, except for DCA, for which low recovery was obtained (30.5%). The limits of detection (LODs) of the substances varied between 0.005 (DCPMU) and 0.026 (M1) μg L⁻¹.     

Hyperfine structure and isotope shift of some even parity levels in the YbI spectrum

Using laser induced fluorescence spectroscopy the hyperfine structure of the even parity levels 4f ¹⁴6s6d ³ D ₁, 4f ¹⁴ 6s8s ³ S ₁ and 4f ¹³ 5d6s6p (7/2, 5/2)J=1,2,3 as well as of the odd parity level 4f ¹⁴ 6s6p ³ P ₂ in neutral ytterbium has been investigated. The isotope shift of the transitions 4f ¹⁴6s6p ³ P ₀ → 4f ¹⁴ 6s6p ³ D ₁ and 4f ¹⁴ 6s6p ³ P ₂ → 4f ¹⁴ 6s8s ³ S ₁, 4f ¹³ 5d6s6p (7/2, 5/2)J=1,2,3 could be measured with high accuracy. The results for the 4f ¹⁴ 6s6p ³ D ₁ level show a considerable influence of second order effects of the hyperfine interaction. The isotope shifts of the 4f ¹⁴ 6s8s ³ S ₁ and 4f ¹³ 5d6s6p (7/2, 5/2)J=1 levels indicate a possible configuration mixing for these levels.     

Synthesis of certain 6-alkylthio-2,2′-anhydro-5-azauridines

β-D-Arabinofurano[1′,2′:4,5]oxazolo-s-triazin-4-one-6-thione ( 7b ) and its t-butyldimethylsilyl protected counterpart 7a were synthesized by treating the appropriate 2-amino-β-D-arabinofurano[1′,2′:4,5]-2-oxazoline with ethoxycarbonyl isothiocyanate. These 2,2′-anhydro-s-triazine nucleosides were then subjected to alkylation under similar reaction conditions. Alkylation of 3′,5′-bis(O-t-butyldimethylsilyl)-β-D-arabinofurano[1′,2′:-4,5]oxazolo-s-triazin-4-one-6-thione ( 7a ) provided the targeted S-alkylated nucleosides, i.e., the C6-SCH₃ ( 9a ), C6-SCH₂-CH = CH₂ ( 10a ), and C6-S-CH₂-C = CH ( 11a ), in reasonable yields. Attempted deprotection of these nucleosides failed. In order to circumvent this problem, 7b was alkylated with the same reagents. In each case, instead of the expected S-alkylated anhydronucleosides, a mixture of the 5-N-alkylanhydro-s-triazine-4,6-dione and 5-N-alkylanhydro-s-triazin-4-one-6-thione derivatives were obtained. The 2,2′-anhydro linkage of 7a was also found to be more stable than the s-triazine ring to mild base. Basic conditions displaced the C6-sulfur substituent and eventually caused ring opening of the s-triazine aglycone.     

Determination of two antifouling booster biocides and their degradation products in marine sediments by high performance liquid chromatography-diode array detection

A method for the simultaneous determination of two antifouling booster biocides, diuron [1-(3,4-dichlorophenyl)-3,3-dimethylurea] and irgarol 1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine) and their degradation products, DCPMU [1-(3,4-dichlorophenyl)-3-methylurea], DCPU [1-(3,4-dichlorophenyl) urea], DCA [3,4-dichloroaniline] and M1 (2-methylthio-4-tert-butylamino-s-triazine), in marine sediments by high performance liquid chromatography-diode array detection (HPLC-DAD) was developed. The extraction of these compounds from sediment was achieved by means of methanolic ultrasonic extraction. The optimization of the extraction procedure included the variation of the volume of the extraction solvent, the amount of the extracted sediment, the duration and the temperature of sonication. C18 solid phase extraction (SPE) cartridges were used for the cleaning of the extracts. The relative standard deviations (R.S.Ds) of the developed procedure was <10% for all the tested compounds, except for DCA, where R.S.Ds up to 15% were obtained. Satisfactory recoveries were obtained (higher than 80% for all substances), except for DCA, which gave a recovery in the range of 35-50%. The limits of detection (LODs) of the substances varied between 1.7 (DCPU) and 4.0 (DCPMU) ng g⁻¹ of dry sediment.     

Rotational effects on the quantum yield and lifetime of the slow component of fluorescence from s-triazine

The fluorescence quantum yield and lifetime of the slow component of fluorescence obtained along the rotational contour of the 6¹₀ and 6²₀ absorption bands of s-triazine at low pressure show a marked variation. For each band, the quantum-yield spectrum shows a sharp peak at the Q-branch edge, the lifetime spectrum exhibits a valley at the same position.     

Synthesis of a 2-Methyl-4-sulfanilamido-s-triazine derivative

An attempt to obtain 2-methyl-4-sulfanilamido-s-triazine (XXI) by condensation of 2-amino-4-methyl-s-triazine (II) with p-acetamidobenzenesulfonyl chloride (III) in pyridine and in benzene containing trimethylamine gave instead the unexpected products, guanidine N-acetylsulfanilate (IV) (after hydrolysis) and N¹,N¹-dimethylsulfanilamide (V), respectively. On the other hand, 2-methyl-4-methylthio-6-sulfanilamido-s-triazine (XIX) was obtained from 4,6-dimethylthio-s-triazine (XVII), but the reduction of XIX with Raney nickel in aqueous sodium hydroxide solution also gave an unexpected compound, sulfaguanidine (XX).     

Microwave-assisted synthesis and reversed-phase high-performance liquid chromatographic separation of diastereomers of (R,S)-baclofen using ten chiral derivatizing reagents designed from trichloro-s-triazine

Four dichloro-s-triazine (DCT) and five monochloro-s-triazine (MCT) chiral derivatizing reagents (CDRs) were synthesized by incorporating amino acid amide moieties as chiral auxiliaries in trichloro-s-triazine and its 6-methoxy derivative, respectively. Another MCT reagent was synthesized by substitution of two chlorine atoms with two different amino acid amides in trichloro-s-triazine. These reagents were used for synthesis of diastereomers of (R,S)-baclofen under microwave irradiation (i.e. 60 s at 85% power using DCT reagents and 90 s at 85% power using MCT reagents). The diastereomers were separated on a reversed-phase C18 column using mixtures of methanol with aqueous trifluoroacetic acid (TFA) with UV detection at 230 nm. The separation behavior in terms of retention times and resolutions obtained for the two sets of diastereomers prepared with DCT and MCT reagents were compared among themselves and among the two groups. Longer retention times and better resolutions were observed with DCT reagents as compared to MCT reagents. The calibration curves were linear for both (R)- and (S)-baclofen in the concentration range 50-500 μg/ml. The average regression was 0.999 for both (R)- and (S)-baclofen. The RSD for (R)-baclofen was 0.40-0.86% for intra-day precision and 0.60-1.40% for inter-day precision and these values for (S)-baclofen were 0.52-0.75% and 0.64-1.32%, respectively. The recovery was 97.2-98.9% for (R)- and 97.0-98.9% for (S)-baclofen. The limit of detection was 1.63ng/ml and 1.52ng/ml for (R)- and (S)-baclofen, respectively.     

Syntheses and Structural Investigations of Penta-Coordinated Co(II) Complexes with Bis-Pyrazolo-S-Triazine Pincer Ligands,and Evaluation of Their Antimicrobial and Antioxidant Activities

Two penta-coordinated [Co(^MorphBPT)Cl₂]; 1 and [Co(^PipBPT)Cl₂]; 2 complexes with the bis-pyrazolyl-s-triazine pincer ligands ^MorphBPT and ^PipBPT were synthesized and characterized. Both ^MorphBPT and ^PipBPT act as NNN-tridentate pincer chelates coordinating the Co(II) center with one short Co-N(s-triazine) and two longer Co-N(pyrazole) bonds. The coordination number of Co(II) is five in both complexes, and the geometry around Co(II) ion is a distorted square pyramidal in 1, while 2 shows more distortion. In both complexes, the packing is dominated by Cl…H, C-H…π, and Cl…C (anion-π stacking) interactions in addition to O…H interactions, which are found only in 1. The UV-Vis spectral band at 564 nm was assigned to metal–ligand charge transfer transitions based on TD-DFT calculations. Complexes 1 and 2 showed higher antimicrobial activity compared to the respective free ligand ^MorphBPT and ^PipBPT, which were not active. MIC values indicated that 2 had better activity against S. aureus, B. subtilis, and P. vulgaris than 1. DPPH free radical scavenging assay revealed that all the studied compounds showed weak to moderate antioxidant activity where the nature of the substituent at the s-triazine core has a significant impact on the antioxidant activity.     

Oil-in-water emulsions as suitable working media for the direct polarographic determination of aziprotryne and desmetryne from its organic extracts in water samples

The electroanalytical behavior of the reduction of the herbicides aziprotryne (2-azido-4-isopropylamino-6-methylthio-1,3,5-triazine) and desmetryne (4-isopropylamino-6-methylamino-2-methylthio-1,3,5-triazine) in oil-in-water emulsions is reported. This medium allows the differential pulse polarographic determination of these s-triazines directly from their sample extracts in an appropriate organic solvent. Sodium pentanesulfonate was chosen as the most suitable surfactant to be used as emulsifying agent, whereas ethyl acetate was selected as the organic solvent to form the emulsions. The peak current was maximum in a 0.3 mol L^–1 HClO₄ medium of the continuous aqueous phase for aziprotryne, and at pH 3.0 for desmetryne, and the potential became more negative as the pH increased for both herbicides. The limiting current is diffusion controlled and the electrode process is irreversible. Four electrons are involved in the overall electrochemical reduction process as determined by controlled potential coulometry, whereas the αn_a values suggested that two electrons are involved in the rate-determining step. Using differential pulse polarography, aziprotryne and desmetryne can be determined in the emulsified medium over the concentration ranges 1.0 · 10^–7–1.0 · 10^–4 mol L^–1, with limits of detection of 4.5 · 10^–8 mol L^–1 and 6.6 · 10^–8 mol L^–1, respectively. The method was applied to the determination of aziprotryne and desmetryne in spiked irrigation water. At concentration levels of 6.0 · 10^–7 mol L^–1 aziprotryne and 4.0 · 10^–7 mol L^–1 desmetryne, recoveries of 94 ± 3% and 94 ± 4%, respectively, were obtained after preconcentration on Sep-Pack C₁₈ cartridges. Finally, partial least-squares regression (PLSR) has been used for treatment of the polarographic data obtained from mixtures of aziprotryne, desmetryne and simazine in oil-in-water emulsions. The size of the calibration set was of 29 samples by ninety two current measurements at different potentials. Prediction of the herbicides concentration within the range 1.0 · 10^–6 –1.0 · 10^–5 mol L^–1 was possible.     

Hydrogen-bonded supramolecular poly(ether ketone)s

The preparation of 2,4-diamino-1,3,5-triazine telechelic poly(ether ketone)s (triazine PEKs) and the formation of supramolecular polymers with dodecyl-(α-ω)-bis(5-methyl-1,3-pyrimidine-2,4-dione) were investigated. Both structures interacted by complementing hydrogen-bonding units present at their respective chain ends, this being reminiscent of triple hydrogen bonding in DNA. The preparation of the triazine PEKs started from hydroxyl-terminated poly(ether ketone)s by a nucleophilic displacement reaction with 2,4-diamino-6-(4-fluorophenyl)-1,3,5-triazine. With this method and molecular weight control via the Carothers equation, a series of triazine PEKs with a complete degree of end-group functionalization were prepared. The structure of the polymers was proven by ¹³C NMR spectroscopy and matrix-assisted laser desorption/ionization spectroscopy. When mixed as a 1:1 complex in solution with dodecyl-(α-ω)-bis(5-methyl-1,3-pyrimidine-2,4-dione), short triazine PEKs (molecular weight = 5700 or 10,000) showed a temperature-dependent association behavior visible via dynamic NMR spectroscopy. Additional proof of the formation of a supramolecular, hydrogen-bonded network was derived from solid-state NMR spectroscopy, differential scanning calorimetry, and rheological investigations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 661–674, 2004     

Octahedral iron(II) complexes with pyridyl triazine and bipyridine ligands – synthesis,computational studies,mechanisms and kinetics with 1,10-phenanthroline and 2,2′,6,2″-terpyridine

[Bis(3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine)(2,2′-bipyridine)iron(II)], [Fe(PDT)₂(bpy)]²⁺ (1), [bis(3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine)(2,2′-bipyridine)iron(II)], [Fe(PPDT)₂(bpy)]²⁺ (2), [bis(2,2′-bipyridine)(3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine)iron(II)], [Fe(PDT)(bpy)₂]²⁺ (3), and [bis(2,2′-bipyridine)(3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine)iron(II)], [Fe(PPDT)(bpy)₂]²⁺ (4) have been synthesized and characterized. Substitution of the triazine and bipyridine ligands from the complexes by nucleophiles (nu), namely 1,10-phenanthroline (phen) and 2,2′,6,2″-terpyridine (terpy) was studied in a sodium acetate-acetic acid buffer over the pH range 3–6 at 25, 35, and 45°C under pseudo-first order conditions. Reactions are first order in the concentration of complexes 1–4. The reaction rates increase with increasing [nu] and pH whereas ionic strength has no effect on the rate. Straight-line plots with positive slopes are observed when the k_obs values are plotted against [nu] or 1/[H⁺]. The substitution reactions proceed by dissociative as well as associative paths and the latter path is predominant. Observed low E_a values and negative ΔS^# values support the dominance of the associative path. Phenyl groups on the triazine ring modulate the reactivity of the complexes. The π-electron cloud on the phenyl rings stabilizes the charge on metal center by inductive donation of electrons toward the metal center, resulting in a decrease in reactivity of the complex and the order is 1 < 2 < 3 < 4. Density functional theory (DFT) calculations also support the interpretations drawn from the kinetic data.     

1-Arylethylamino-substituted s-triazine derivatives as chiral solvating agents for the determination of the enantiomeric composition of chiral compounds

The development of 2-[(R)-1-(9-anthryl)ethylamino]-4-chloro-6-methoxy-1,3,5-triazine, 2-[(R)-1-(9-anthryl)ethylamino]-4-chloro-6-[(R)-1-(1-naphthyl)ethylamino]-1,3,5-triazine and 2-[(R)-1-(9-anthryl)ethylamino]-4,6-bis-[(R)-1-(1-naphthyl)ethylamino]-1,3,5-triazine as chiral solvating agents (CSAs) for the determination of the enantiomeric composition of derivatized and underivatized chiral compounds is presented. The comparison between the efficiency of these chiral auxiliaries with the corresponding 1-(1-naphthyl)ethylamino substituted s-triazine derivatives is also discussed.     

The Reactivity of Cyameluric Chloride C6N7Cl3 towards Phosphines and Phosphine Oxides

Organophosphines (R₂PH) and phosphineoxides (R₂OPH) show a very high reactivity towards cyameluric chloride C₆N₇Cl₃. For example, 2,4,6‐trisdiphenylphosphino‐tri‐s‐triazine ( 1 ) forms quantitatively within a few seconds. Tris‐diphenylphosphinsulfide‐s‐heptazine ( 2 ) was obtained by reaction of 1 with sulfur. These compounds represent a new class of s‐heptazine derivatives which tend, unlike their s‐triazine analogues, to decompose in solution. 1 forms crystals with nitromethane, which were analysed by single‐crystal X‐ray diffraction. The nitromethane molecules fill the gaps in the crystal lattice supported by hydrogen bonds, C–H ··· π ring, and N–O ··· π ring interactions. All compounds were characterized by ¹H, ¹³C and ³¹P NMR and vibrational (FT‐IR, Raman) spectroscopy. The thermal stability of selected derivatives was measured by TG, indicating surprisingly low thermal decomposition temperatures.     

Cyanuric and thiocyanuric esters as carriers of boron-containing fragments and their fragmentation in mass spectrometry

Tripropargylic esters 2 and 10 of cyanuric and thiocyanuric acids were synthesized. Interaction of these compounds with disubstituted amines gives monoaminoderivatives of dipropargyloxy-s-triazine 4 and 11. Diaminosubstituted propargyloxy-s-triazine 6 was prepared from the corresponding diaminochloroderivative 5. First examples of boron-containing s-triazines 7, 8, 12, 13 were prepared by reaction of propargyl esters 4, 6, 10, 11 with decaborane. New rearrangements of the molecular ions of the 2-aminoderivatives of 4,6-dipropargyloxy-1,3,5-triazine in mass spectrometry were found.