Showing papers on "Triazene published in 1991"

Studies on 1,3-diaryltriazene analogues of berenil: molecules with potential GC base-pair selectivity.

Abstract: 1,3-Bis(4-acetylphenyl)triazene (II): C16H15N3O2, Mr = 281.32, monoclinic, P2(1)/c, a = 14.002 (5), b = 12.359 (3), c = 8.457 (3) A, beta = 96.35 (2) degrees, V = 1454.5 A3, Z = 4, Dx = 1.287 Mg m-3, Cu K alpha, lambda = 1.54178 A, mu = 0.672 mm-1, F(000) = 592, T = 294 K, final R = 0.089 for 1890 unique observed reflections. 1,3-Bis(4-[2-dimethylamino)ethoxycarbonyl]phenyl)triazene monohydrate (III): C22H29N5O4.H2O, Mr = 445.52, triclinic, P1, a = 9.500 (2), b = 11.753 (3), c = 13.328 (2) A, alpha = 62.84 (1), beta = 66.60 (2), gamma = 77.58 (2) degrees, V = 1214.1 A3, Z = 2, Dx = 1.172 Mg m-3, Cu K alpha, lambda = 1.54178 A, mu = 0.640 mm-1, F(000) = 476, T = 294 K, final R = 0.063 for 1100 unique observed reflections. Both crystal structures have extended conformations for the 1,3-diaryltriazene groups, with a cisoid arrangement of phenyl rings. The terminal N--N bonds of each triazene are non-equivalent, and a hydrogen atom has been located in the N==N--NH moiety. Extensive molecular-orbital (MNDO) calculations on the model core 1,3-diphenyltriazene system have confirmed that this geometry is energetically favoured, and have revealed the shape of the energy surface for rotation about the N--NH bond in the triazene linkage.

New nucleoside tri:phosphoric acid ester derivs. - used for prepn. of polymerase chain reaction probes, amplification of nucleic acid sequences and as chain terminators for sequences

Abstract: New labelled nucleoside triphosphate derivs. (I) are ribonucleosides, 2'-deoxyribonucleosides or 2',4'-dideoxyribonucleosides, opt. in salt form, with a gp. of formula -(A)nQ linked to the nucleoside base, where: n = 0 or 1; A = an optional linking gp. stated to be an amino, alkyl, alkenyl, alkynyl, aryl, aralkyl or alkaryl gp. which may contain one or more terminal or internal structural functional units selected from amino, amido, imino, hydrazino, azo, triazene, keto, ester, hydroxy, ether, thioether, disulphide, ureido and thioureido gps., opt. substd. by alkyl, alkenyl, aryl, alkaryl or aralkyl gps.; Q = a gp. which is capable of complexing lanthanide ions and contains an 'energy donor' for lanthanide ions. Lanthanide complexes of (I) are also new. USE/ADVANTAGE - The complexes may be incorporated in oligonucleotides, e.g. by enzyme-catalysed tailing (using terminal deoxynucleotidyl transferase), to produce fluorescence-labelled hydridisation probes. They may also be used as markers in PCR amplification systems, as chain terminators (in the case of the dideoxy derivs.) in nucleic acid sequencing systems, and as tracers for measuring nucleic acid synthesis in vitro or in vivo. The lanthanide label can be detected by time-resolved fluorometry, which eliminates interference from autofluorescence and light scattering.

Triazene drug metabolites. Part 10. Metal-ion catalysed decomposition of monoalkyltriazenes in ethanol solutions

Abstract: The metal ions Fe2+, Zn2+ and Cu2+ bring about the rapid decomposition of 1-aryl-3-alkyltriazenes to the corresponding anilines. For Fe2+, a linear dependence of the pseudo-first-order rate constant, k0 on [Fe2+] was observed, while for Zn2+ and Cu2+ plots of k0versus[metal ion] were curved and indicative of complex formation. For Fe2+, second-order rate constants k2Fe2+ for substituted 1-aryl-3-methyltriazenes follow a Hammett relationship giving rise to a ρ value of –3.0. For Zn2+ and Cu2+, the data were analysed in terms of an equilibrium constant, KM2+, for the dissociation of a metal-ion-triazene complex and the first-order rate constant for the collapse of this complex to products, k2M2+. Hammett ρ values of 1.0 for both KZn2+ and KCu2+ are found, and the corresponding ρ values for k2Zn2+ and K2Cu2+ are –1.3 and –1.9. There is reasonable correlation between the Taft Es parameter for the alkyl group and KCu2+, giving a δ value of –1.6. The dependence of k2Cu2+ on the alkyl group is not simple: k2Cu2+ decreases in the order Pr > Et ≠ PhCH2ca. 4-MeOC6H4CH2 > CD3ca. Me. The reactions catalysed by Cu2+ are inhibited by added nucleophilies e.g. Br– and N-methylimidazole.A mechanism is proposed in which the triazene complexes to the metal ion via the N(1) nitrogen atom of the E–cis conformer, then undergoes a fast proton transfer to form a complex involving the unconjugated tautomer which subsequently decomposes via unimolecular scission of the N(2)–N(3) bond to form an alkyldiazonium ion and an aniline–metal complex. The observed products then arise from rapid solvolysis of the metal–aniline complex and the alkyl diazomum ion.

Synthesis and antitumor activity of hydrosoluble analogs of p-(3,3-dimethyl-1-triazeno) benzoic acid potassium salt.

Abstract: The hydrosoluble triazene derivatives of phenylacetic, phenylbutyric and cinnamic acid have been synthesized and their logP and pKa values were simultaneously determined according to a multiparametric fitting of potentiometric data. The antitumor activity caused by the synthesized compounds in mice bearing either Lewis lung carcinoma or TLX5 lymphoma was evaluated and discussed in comparison with the parent compound (p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK, CAS 70055-49-1). The tested compounds were at least as active as DM-COOK, the cinnamic and the phenylacetic derivatives being the more active compounds in mice bearing TLX5 lymphoma and Lewis lung carcinoma, respectively.

Synthesis of 1-phenyl-3,3-dimethyltriazene 2-oxide and the corresponding triazene from nitro compounds and N-magnesium bromides

Abstract: The reaction of dimethylnitramine with Ph-N(MgBr)2 gives 1-phenyl-3,3-dimethyl-triazene 2-oxide, which is the first reported triazene 2-oxide. The reaction of nitrobenzene with Me2NNHMgBr gives only the corresponding triazene.

Synthesis and Characterisation of Cu(II), Pd(II), Ni(II), Co(II) and Zn(II) Bis(3-thiazolyl/aryl-1-aryl/alkyl-triazene-1-oxide) Square Planar and Tetrahedral Complexes

Abstract: Bis complexes of the general formula M(TO)2 (M = Cu, Pd, Ni, Co or Zn; HTO = l-methyl(or ethyl or phenyl)-3-thiazolyl (or phenyl) triazene-1-oxide) have been prepared by the reaction of metal salts with the appropriate ligands. The complexes have been characterized by elemental analyses, IR, UV and reflectance spectra, PMR, magnetic susceptibilities and molecular weight determinations. These ligands form low spin 1:2 (metal:ligand) five-membered chelates. Formation constants of some of the metal complexes are reported and correlated with 10 Dq values.