Showing papers on "Triazene published in 2004"

The virtue of the multifunctional triazene linkers in the efficient solid-phase synthesis of heterocycle libraries.

Abstract: With the implementation of combinatorial chemistry into the modern drug discovery process, the approach to novel diverse heterocycle libraries is an indispensable requirement. Triazenes, which are concealed diazonium salts, can be used to link functionalized arenes and amines to generate various heterocyclic structures, namely, benzoannelated nitrogen heterocycles, upon cleavage from the resin. Since triazene anchors are stable toward various reagents and perform well under a range of reaction conditions, these multifunctional linkers are well suited for automated solid-phase syntheses and the syntheses of complex organic molecules, such as natural products, on solid supports.

Palladium-Catalyzed Cross-Coupling Reaction of 1-Aryltriazenes with Aryl- and Alkenyltrifluorosilanes

Abstract: The palladium-catalyzed cross-coupling reaction of 1-aryltriazenes with aryl- and alkenyltrifluorosilanes occurs readily at room temperature to yield the corresponding biaryl and stilbene products in moderate to good yields. In contrast to the previous results for the reaction with areneboronic acids, in which an additional Lewis acid such as boron trifluoride is essential for the activation of the 1-aryltriazenes, the Lewis acidity of organotrifluorosilanes seems to be strong enough to directly activate the triazene moiety to enter into the palladium-catalyzed cross-coupling reaction without an extra Lewis acid.

3-Hydroxy-4-oxo-3,4-dihydro-5-azabenzo-1,2,3-triazene†

Abstract: The known but long-neglected compound HODhat was shown to be in certain situations a useful peptide coupling additive. Uronium and phosphonium salts with HODhat built into the system were also useful stand-alone coupling reagents. Comparisons with related additives and coupling reagents showed that the new systems were sometimes more and sometimes less effective than previously described systems in the case of stepwise and segment couplings. Applications to assembly of the model decapeptide ACP showed that HDATU was far more effective than HDTU and more effective than HATU under some conditions.

Synthesis and characterization of a series of 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes and 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes

Abstract: 1-Methylhomopiperazine was coupled with a series of diazonium salts to afford the 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes (6), a new series of triazenes. These compounds are, in the main, stable crystalline solids (some of the series are stable oils), and they have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectrometry. NMR assignments were determined by 2D NMR and variable-temperature NMR experiments and by comparison with model compounds. A second series of new compounds, namely, 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes (5), were prepared by coupling unsubstituted homopiperazine (1,4-diazepane) with 2 molar equivalents of the diazonium salt and were similarly characterized. The crystal and molecular structure of the parent member of this bis-triazene series (5, X = H) has been determined by single-crystal X-ray diffraction analysis.Key words: triazene, bis-triazene, diazenyl, bis-diazenyl, diazonium salt, NMR, diazepane.

Synthesis and characterization of a series of 1-methyl-4-[2-aryl-1-diazenyl]piperazines and a series of ethyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates

Abstract: 1-Methylpiperazine was coupled with a series of diazonium salts to afford the 1-methyl-4-[2-aryl-1-diazenyl]piperazines (2), a new series of triazenes, which have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analysis. Assignment of the chemical shifts to specific protons and carbons in the piperazine ring was facilitated by comparison with the chemical shifts in the model compounds piperazine and 1-methylpiperazine and by a HETCOR experiment with the p-tolyl derivative (2i). A DEPT experiment with 1-methylpiperazine (6) was necessary to distinguish the methyl and methylene groups in 6, and a HETCOR spectrum of 6 enabled the correlation of proton and carbon chemical shifts. Line broadening of the signals from the ring methylene protons is attributed to restricted rotation around the N2-N3 bond of the triazene moiety in 2. The second series of triazenes, the ethyl 4-[2-phenyl-1-diazenyl]-1-piperazinecarboxylates (3), have been prepared by similar diazonium coupling to et...

4-( E )-2-[3-(3-[( E )-2-(4-cyanophenyl)-1-diazenyl]perhydrobenzo[ d ]imidazol-1-ylmethyl)perhydrobenzo[ d ]imidazol-1-yl]-1-diazenylbenzonitrile: X-ray crystal structure

Abstract: 4-(E)-2-[3-(3-[(E)-2-(4-Cyanophenyl)-1-diazenyl]perhydrobenzo[d]imidazol-1-ylmethyl) perhydrobenzo[d]imidazol-1-yl]-1-diazenylbenzonitrile (1) has been synthesized by reac- tion of p-cyanobenzene diazonium chloride with a mixture of formaldehyde and trans-1,2-cyclohexanediamine. The crystal structure has been determined by single crystal X-ray diffraction analysis. The bis-triazene (1) does not adopt a folded conformation, unlike previously studied ethylenediamine analogues, and there is no indication of π-stacking in the crystal packing. The dominant interaction between molecules is the van der Waal's attraction between cyclohexane rings. This result establishes the structure of the product of this diazonium coupling reaction as the 1-(1-imidazolidinylmethyl)imidazolidine derivative and not the alternate tetraazabicyclo[4.4.1]undecane derivative. Crystal data: 1 C29H34N10, orthorhombic, space group Pbca, a = 17.946(1), b = 13.106(1), c = 24.108(1) A, V = 5670.6(3) A3, for Z = 8.

New polyurethane cationomers with naphthyl and phenyltriazene pendants: Synthesis and properties

Abstract: Two new diols bearing triazene moiety, 1-(α-naphthyl)-3,3-di(2-hydroxyethyl) triazene-1 (NT-D) and 1-phenyl-3,3-di(2-hydroxyethyl) triazene-1 (PT-D), were synthesized from aromatic amines and diethanolamine. These monomers were used as chain coextenders in the two-step addition reaction between poly(tetramethylene oxide) diol, 2,4-tolylene diisocyanate, and N-methyldiethanolamine to obtain photosensitive polyurethanes of elastomer type. Triazene polyurethane cationomers with chlorine counterions were prepared via a quaternization reaction of the above polymers with benzyl chloride. All polyurethanes had a quantity of triazene units between 7.02 and 8.93 wt % polymer, and the content of ammonium quaternary groups in the cationic ones was of 30.56 meq/100 g naphthyl triazene polyurethane cationomer (PUC-NT) and 30.19 meq/100 g phenyl triazene polyurethane cationomer (PUC-PT), respectively. Photobehavior of the triazene units in all polymers under continuous Hg-lamp irradiation was similar to that found for monomers, when both chromophores were transformed during UV irradiation. It is concluded that the PT-D acts as a more efficient sensitizer in the UV light-induced reaction but the photolysis in elastomeric films was lower than that observed in solution. The presence of quaternary ammonium structure on the same polymer backbone decreases the constant rates of photolysis. Because the triazene polyurethanes become crosslinked during UV irradiation could be assessed as potential negative-resist polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2599–2605, 2004

Synthesis of Aryl Azides via Post-Cleavage Modification of Polymer-Bound Triazenes

Abstract: Starting from immobilized arenes on the triazene T1 linker resin, cleavage was achieved by trifluoroacetic acid in the presence of trimethylsilyl azide to obtain aryl azides in good yields and excellent purities. A novel cleavage protocol has been introduced and analytical and preparative applications have been presented.

M...HNR interactions in imino-bound diaryltriazene complexes: structure and fluxionality.

Abstract: The nominally square-planar coordination of the d8 complexes [MClL1L2(p-XC6H4NNNHC6H4X-p)] (M = Rh, L1 = L2 = CO, X = H, Me, Et or F; M = Ir, L1 = L2 = CO, X = Me; M = Pd or Pt, L1 = Cl, L2 = PPh3, X = Me; M = Pd, L1L2 = η3-C3H5, X = Me), with the triazene N-bonded via the imine group, is supplemented by an axial M⋯H–N interaction involving the terminal amino group.

3-Butyl-1-(5-nitrobenzo[c] [1,2]-thiazol-3-yl)-3-phenyltriazene

Abstract: The molecule of the title compound, C(17)H(17)N(5)O(2)S, consists of three pi systems, viz. two aromatic rings and the triazene moiety, which are mutually deconjugated although coplanar. The n-butyl chain is roughly perpendicular to the molecular plane, with the terminal methylene and methyl groups disordered between two equally populated positions. The molecules in the crystal associate in an antiparallel fashion, forming dimers across the centre of symmetry, the principal intradimer interaction being stacking of the pi-electron portions of the molecules.

Synthesis and Antiproliferative Activity of Triazenoindazoles and Triazenopyrazoles: A Comparative Study.

Abstract: Several triazenoindazoles and triazenopyrazoles were prepared transforming the appropriate aminoindazoles and aminopyrazoles in the corresponding diazonium salts which were reacted with dimethylamine, diethylamine and pyrrolidine. All the triazenes were tested for their antiproliferative activity against K562, HL60, L1210 and MCF7 cell lines. The biological data showed that the benzocondensation plays a positive role on the antiproliferative activity. The (1)H-NMR spectra showed that the rotational barrier around the N(2)-N(3) bond in the triazene group can be influenced both by the position of this group in the indazole nucleus and by the substitution pattern in the benzene moiety.

Preparation method of triazene polymer chelant and its application

Abstract: A process for preparing triazene as high-molecular chelating agent features that the functional group "-S-" is introduced to the adjacent position of amino in a compound. It has strong chelating action to heavy metal ions (such as Cd and Hg) and excellent regeneration performance.

Bis[1,3-bis(2-methyltetrazol-5-yl-κn4) triazenido-κn2]nickel(II)

Abstract: The title compound, [Ni(BMTT)2], where BMTT is 1,3-bis(2-methyl­tetrazol-5-yl)­triazenide (C4H6N11), presents a molecular complex with tridentate ligands. The tridentate mode of the ligand is realised through the central N atom of the triazene group and two N atoms of the two tetrazole rings. The [Ni(BMTT)2] mol­ecule is the meridional isomer, with crystallographic \overline 4 symmetry in space group P42/n. The nickel centre has a distorted octahedral environment, with two axial Ni—N bonds of 2.041 (2) A and four equatorial Ni—N bonds of 2.0739 (14) A. The mol­ecules are linked together by van der Waals interactions only.

3-(4-Acetylphenyl)-1-(4-nitrophenyl)triazene.

Abstract: The crystal structure of the title compound, C(14)H(12)N(4)O(3), shows that the stereochemistry about the N=N double bond of the N=N-N(H) moiety is trans. The whole molecule is almost planar (r.m.s. deviation = 0.0654 A), the interplanar angle between the phenyl rings being 0.7 (1) degrees and the largest interplanar angle being that between the phenyl ring and the nitro group of the 4-nitrophenyl substituent [11.5 (2) degrees ]. Intermolecular N-H.O interactions between molecules related by translation give rise to chains along the [110] and [1-10] directions, and these chains are held together by N.O pi-pi interactions. An unequal distribution of the double-bond character among the N atoms suggests a delocalization of pi electrons over the diazoamine group and the adjacent aryl substituents.

Polymerisation catalysts with triazenido ligands

Abstract: A polymerisation catalyst comprising (1) a nitrogen-containing transition metal compound of Formula (A), and (2) an organoaluminium or hydrocarbylboron activator, wherein either (a) R1 and R2 are monovalent groups or (b) R1 and R2 integrally form a divalent group R3 bridging the terminal nitrogen atoms of the triazene unit via carbon atoms; R1 and R2 and the divalent group R3 are (i) aliphatic hydrocarbon, (ii) alicyclic hydrocarbon, (iii) aromatic hydrocarbon, (iv) alkyl substituted aromatic hydrocarbon (v) heterocyclic groups and (vi) heterosubstituted derivatives of said groups (i) to (v); M is a metal from Group 3 to 11 of the Periodic Table or a lanthanide metal; X is an anionic group, L is a neutral donor group; n is 1 or 2, y and z are independently zero or integers such that the number of X and L groups satisfy the valencyand oxidation state of the metal M. The catalyst is used to polymerise 1-olefins especially ethylene and propylene. High molecular weight homo- and co-polypropylene are disclosed.