Benzotriazole Ring Research Articles

Structural and conformational analysis of 1,2-bis(benzotriazol-1-yl)ethane

The compound 1,2-bis(benzotriazol-1-yl)ethane (BBTA) was prepared and its structure was determined by X-ray analysis. The compound crystallizes in monoclinic space group P2 1/c with a=7.526(2) Å, b=10.836(2) Å, c=8.412(2) Å, β=116.629(5)°, V=613.2(3) Å 3, Z=2, and D=1.431 Mg/m 3. The structure was solved by direct methods and refined to R=0.0537 and wR 2=0.1302 by full matrix anisotropic least-squares methods. The molecular geometry of the anti-BBTA in the ground state has been calculated using the restricted Hartree–Fock and density functional method (B3LYP) with 6-31G * basis set. The optimized geometric bond lengths and bond angles obtained by using B3LYP/6-31G * are better agreement with the experimental values than those by using RHF/6-31G *. The conformers located at minima by RHF/STO-3G calculation were re-optimized by using B3LYP/6-31G * method. Two anti conformations (A(1) and A(2)) and two gauche conformations (G(1) and G(2)) were obtained. The B3LYP/6-31G * relative energies for A(1), A(2), G(1) and G(2) conformers are 0.00, 1.09, 1.52 and 2.07 kcal/mol, respectively. In addition, a qualitative estimation of the chemical behaviors of the stable conformers has been investigated by analyzing charges of the nitrogen atoms in the benzotriazole ring.

Surface enhanced Raman scattering of benzotriazole: a molecular orientational study

Surface enhanced Raman scattering of benzotriazole in aqueous silver sol at pH ∼9 has been investigated. The spectra of the molecule at various concentrations were recorded and the maximum enhancement was observed with a 10 −5 M solution. From the comparison of the surface enhanced Raman spectra with the conventional Raman spectra and applying ‘surface selection rule’, it is inferred that the molecular ion interacts with the silver sol via the nitrogen atoms of the benzotriazole ring and the molecule assumes a near ‘end-on’ orientation.

Structure of benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP)

The crystal structure of a coupling reagent-benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate has been determined. The compound crystallizes in monoclinic system with a space group P2 1/ n and contains four molecules per unit cell. The benzotriazole ring is connected through the oxygen atom to the phosphorus one, which is bonded to three dimethylamino groups. The anion is the hexafluorophosphate. The 31P and 1H NMR spectra in DMSO solution supports the structure found for the crystalline state. There are no conformational restrictions on both chemical bonds connecting the two parts of the molecule through the oxygen atom in DMSO solution.

ROLE OF WEAK INTERACTIONS IN THE STRUCTURE OF 3-(α,α′-DIBROMOMETHYL)BENZYL 1-4 BENZOTRIAZOLE (DBT)

3-(α,α′-Dibromomethyl)benzyl 1-4 benzotriazole, C14H11Br2N3, F.W.=381.08, triclinic, P1¯ a=8.411(1)Å, b=9.008(1)Å, c=9.714(1)Å, α=97.74(1)°, β=103.11(1)°, γ=101.62(1)°,V=689.4(1)Å3, Z=2, Dcal=1.836 Mgm−3, μ=7.364 mm−1, λ(CuKα)=1.5418 Å, final R1 and wR2 are 0.0538 and 0.1383, respectively.The title compound is a precursor for the macroligand stilbenobenzotriazolophane. Unusual short bond length in the benzotriazole ring suggests the delocalization effect on the bonding. Intermolecular C–H…π, C–H…Br, and some face-to-face π-π interactions play a role in stabilizing the delocalized form. The molecules in the unit cell are stabilized by C–H…N type of interactions in addition to van der Waals forces.

A novel rearrangement to 1,2,4-triazolo[1,5-a]quinoxalines.

Reactions of benzyl bromide or benzyl cinnamate with N-(benzotriazol-1-ylmethyl)arylimidoyl chlorides (2a,b) in the presence of t-BuOK occur with opening of the benzotriazole ring affording 1,2,4-triazolo[1,5-a]quinoxalines (3a,b). A possible reaction mechanism is discussed.

Synthesis of E/Z 3-(1H-Benzotriazol-1-yl)-3-(pyridin-4-yl)acrylonitriles and E/Z 2-(3-Imino-2-benzofuran-1(3H)-ylidene)acetonitriles. An Unusual Case of Displacement of the Benzotriazole Ring

Synthesis of 3-(1H-benzotriazol-1-yl)-3-(pyridin-4-yl)acrylonitriles (E/Z 6) and 2-(3-imino-2-benzofuran-1(3H)-ylidene)acetonitriles (E/Z 20), by an unusual case of displacement of the benzotriazole ring, has been described. The X-Ray structure analysis of Z 20 and antimycobacterial activity of both E/Z 6 and E/Z 20 were also reported.

Some structural changes on triazolyl-benzotriazoles and triazolyl-benzimidazolones as potential potassium channel activators. III

This paper reports the synthesis and pharmacological evaluation of some compounds, obtained by structural modifications of 1,2,3-triazolyl-benzotriazoles and 1,2,3-triazolyl-benzimidazolones, which had shown activity as potential activators of the big-conductance calcium-activated potassium channels (BK Ca). Changes have concerned the introduction of a hinderer substituent in the 5-position of the benzimidazolone ( 4a, b) and benzotriazole ( 5a, b) rings, opening of the benzimidazolone ring ( 7) and substitution of the 1,2,3-triazole ring with a 2-hydroxyphenyl ring ( 10). Furthermore a series of 3-aryl-benzotriazin-4-one derivatives ( 13a– e) has been studied, which appears as a modification and/or combination of the benzimidazolone and benzotriazole rings. Only compound 10 shows interesting activity, while the other structural modifications either do not increase (compounds 4 and 5) or reduce (compounds 7 and 13) the pharmacological activity. However, these results provide useful information about structure–activity relationships.

New 5-substituted-1-(2-hydroxybenzoyl)-benzotriazoles, potassium channel activators. IV

This paper reports the synthesis of a series of new 5-substituted-1-(2-hydroxybenzoyl)-benzotriazoles, which have been tested for their activity as possible activators of potassium channels. In rat aortic rings, the ‘opened’ derivatives 1a– f, intermediates of synthesis, showed vasorelaxing properties, with appreciable values of potency. However, the most remarkable effects were recorded for the 2-hydroxybenzoylbenzotriazoles 3a– f, which showed full vasorelaxing efficacy and high potency values. The introduction of a 2-hydroxybenzyl substituent in the 1 position of the benzotriazole ring (compound 7) strongly decreased the activity, showing the importance of the electron-acceptor carbonyl function. The best compound, 3b, was further investigated, in order to evaluate the possible mechanism of action involved in the vasodilator activity. In the vascular model, different potassium channel blockers inhibited the effects of the compound, and an increase of the levels of membrane depolarisation induced a significant reduction of the recorded responses. Compound 3b was also tested in a model of isolated rat heart, retroperfused through the aorta and submitted to a global ischemia/reperfusion cycle. In such an experimental condition, 3b showed an interesting cardioprotective activity. All the above observations are in agreement with the hypothesis of a mechanism linked to the activation of potassium channels.

NMR Evidence for Cationic Behaviour of the Benzotriazole Ring in Novel α-(benzotriazol-1-yl)-N-acylglycines

Spin coupling of a proton to a nitrogen in the benzotriazole ring of novel α-(benzotriazol-1-yl)-N-acylglycines 1–3 revealed the zwitterionic properties of these compounds.

A Short and Efficient Synthesis of Novel N-(2,3-dihydro-2-oxo-5-phenyl-1 H-1,4-benzodiazepin-3-yl)-2-carboxamides

Several novel N-(2,3-dihydro-2-oxo-5-phenyl-1H-1,4-benzodiazepin-3-yl)-2-carboxamides were prepared by acyl coupling of 2-aminobenzophenones with α-(benzotriazol-1-yl)-N-acylglycines followed by displacement of the benzotriazole ring with ammonia and cyclization of the resulting monoacyl aminals. In addition to high yields and shorter reaction sequences due to avoiding deprotection and acylation of the protected 3-amino-1,4-benzodiazepin-2-one intermediates, the present approach did not involve the use of toxic and odoriferous materials as is the case with other methods.

Synthesis and pharmacological evaluation of aryl/heteroaryl piperazinyl alkyl benzotriazoles as ligands for some serotonin and dopamine receptor subtypes

Thirteen [(aryl/heteroaryl-piperazinyl)alkyl]benzotriazoles were prepared as potential trazodone- and buspirone-like drugs. The synthesized compounds displayed from moderate to good affinity to the serotonin 5-HT 1A receptor and only modest or poor affinity to the dopamine D 2 receptor, similar to buspirone. The introduction of substituents on the benzotriazole ring did not improve the affinity to the 5-HT 1A receptor, compared to the previously described unsubstituted derivatives. In a general pharmacological screening, which concerned only three of these compounds so far ( 5, 7 and 13), several in vitro and in vivo activities were observed. The guinea pig ileum contractions, induced either electrically or by several agonists, were strongly inhibited; at higher concentrations also the spontaneous tone of the guinea pig trachea was reduced. Compound 13 exhibited good analgesic activity in mice in the formalin-induced algesia and in the writhing test. The same at 30 mg kg −1 p.o. also displayed antihypertensive activity probably related to calcium channel blockade and adrenergic α 1 antagonism. In binding assays, 13 showed a IC 50=580 nM for displacing [ 3H]prazosin from α 1 receptor. Finally, compound 5 (and, to a minor extent, compound 13) protected mice against potassium cyanide induced hypoxia.

Triazolyl–benzimidazolones and triazolyl–benzotriazoles: new potential potassium channel activators. II

This paper reports the synthesis and pharmacological evaluation of a series of 5-substituted-triazolyl–benzotriazoles ( 2a–f) and the corresponding series of 5-substituted-triazolyl–benzimidazolones ( 6a–f), as potential activators of the big-conductance calcium-activated potassium channels (BK Ca). The synthesis and structure demonstration of the stock compounds of the two series have been described in our previous works, as well as the common starting compounds 4-carboxamido-5-(4-substituted-2-amino-anilino)-1,2,3-triazoles ( 1a–f). The triazolyl–benzotriazoles were obtained by diazotization, while the triazolyl–benzimidazolones were obtained by thermal intramolecular cyclization of ethoxycarbonylamino derivatives or directly with phosgene. Benzimidazolone compounds generally showed little effect whilst the compounds with a benzotriazole ring showed full efficacy, with vasorelaxing properties and potency parameters a little lower than that of the reference compound NS 1619. These effects were significantly reduced by an increased membrane depolarization. This depolarization-sensitive response is in agreement with the pharmacodynamic hypothesis of activation of potassium channels.

Self-assembly and X-ray structure of a triple helicate with two trigonal silver(I) termini

Reaction of the new ligand 1,3-bis(benzotriazol-1-ylmethyl)benzene ( 1) with silver nitrate results in the efficient self-assembly, about two silver(I) atoms, of a saturated homotopic triple-stranded helicate ( 2), the X-ray crystal structure of which is described. It consists of two silver atoms bridged, in a helical sense, by three molecules of 1, each of which coordinates through the N3 nitrogens of the benzotriazole rings. The helicates further associate into a tetranuclear species with a relatively short Ag···Ag contact.

A Vibrational Structural Analysis of Benzotriazole Adsorption and Phase Film Formation on Copper Using Surface-Enhanced Raman Spectroscopy

The adsorption of benzotriazole (BTAH) on copper in aqueous electrolytes is examined by means of a vibrational analysis utilizing surface-enhanced Raman spectroscopy (SERS) as a function of solvent deuteration, pH, and electrode potential in order to examine adsorbate speciation, surface bonding, and the potential-dependent onset of CuIBTA phase film formation. In acidic media at pH > 1, the monoprotonated acid BTAH constitutes the predominant adsorbate, being replaced by the diprotonated BTAH2+ species by pH 0, and the basic BTA- form in alkaline electrolytes. The analysis of adsorbate speciation is facilitated by the presence of several coupled ring modes yielding vibrational bands in the 1050−1350 cm-1 region that are sensitive to deuteration of the triazole ring nitrogen(s). Insight into the adsorbate molecular geometry and mode of surface attachment is obtained by examining the adsorption-induced alterations in frequency, bandwidth, and relative intensity of the various benzotriazole ring modes. These changes are especially prevalent for triazole ring vibrations and some deuteration-sensitive modes, the latter apparently associated with Fermi resonance effects. The former torsional/bending ring vibrations also exhibit potential-dependent frequencies (i.e., an electrochemical Stark effect), reflecting copper−triazole electronic interactions. Taken together, the SER spectral features for BTAH and BTA- suggest surface attachment via a pair of triazole nitrogens with a tilted (or vertical) orientation; the single nitrogen binding site anticipated for BTAH2+ is consistent with the milder vibrational perturbations observed for this adsorbate. The transformation from adsorbed benzotriazole to a CuIBTA film at higher potentials is readily diagnosed from the SER spectra, including the observed lack of a D/H vibrational effect on the latter species. The structure of benzotriazole films in air is also examined; emersion of adsorbed BTAH from solution spontaneously yields a CuIBTA layer via a coupled O2-induced electrochemical pathway. The thermal stability of copper-benzotriazole films in ambient-pressure O2 and N2 from 25 to 300 °C was also probed with SERS.

ChemInform Abstract: Formation of 1‐(2‐Aminophenyl)‐5‐ethoxy‐4‐methyl‐3‐phenylpyrazole (II) and 3‐Methyl‐2‐phenylpyrazolo(5,1‐b)benzimidazole (III) via an Unusual Benzotriazole Ring Opening.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Functional Polymers. 61. Ultraviolet Spectral Behavior of Selected 2(2-Hydroxyphenyl)2H-Benzotriazoles

Abstract Ultraviolet spectra of a number of 2(2-hydroxyphenyl)2H-benzotriazoles were studied in nonpolar, polar, and hydrogen bonding solvents. The effect of substituents located in the 4-position of the benzotriazole ring was investigated, and the effect on the UV absorption characteristics of 2(2-hydroxyphenyl)2H-benzotriazoles was determined. Substituted resorcinol or phloroglucinol-based 2(2-hydroxyphenyl)2H-benzotriazole derivatives were investigated with special emphasis on UV absorption characteristics that were expected to be useful as polymerbound UV stabilizers in optical lens applications.

Pharmacological evaluation of benzotriazole derivatives structurally related to trazodone

Thirteen [(aryl/heteroaryl-piperazinyl)alkyl]benzotriazoles were prepared as potential trazodone- and buspirone-like drugs. The synthesized compounds displayed from moderate to good affinity to the serotonin 5-HT1A receptor and only modest or poor affinity to the dopamine D2 receptor, similar to buspirone. The introduction of substituents on the benzotriazole ring did not improve the affinity to the 5-HT1A receptor, compared to the previously described unsubstituted derivatives. In a general pharmacological screening, which concerned only three of these compounds so far (5, 7 and 13), several in vitro and in vivo activities were observed.The guinea pig ileum contractions, induced either electrically or by several agonists, were strongly inhibited; at higher concentrations also the spontaneous tone of the guinea pig trachea was reduced. Compound 13 exhibited good analgesic activity in mice in the formalin-induced algesia and in the writhing test. The same at 30 mg kg−1 p.o. also displayed antihypertensive activity probably related to calcium channel blockade and adrenergic α1 antagonism. In binding assays, 13 showed a IC50=580 nM for displacing [3H]prazosin from α1 receptor.Finally, compound 5 (and, to a minor extent, compound 13) protected mice against potassium cyanide induced hypoxia.

4-(Benzotriazol-1-yl)-6H-benzo[c]tetrazolo[1,5-e][1,2,5]triazepine. A new heterocyclic ring system formed by a novel benzotriazole ring opening

Le compose du titre, dont la structure cristalline est donnee, est prepare via la decyclisation d'un groupe triazole present dans le 1-azido-1,2-bis[benzotriazol-1-yl]ethylene

Studies on the thermal isomerization of N-arylmethylbenzotriazoles

The thermal isomerizations of N-benzyl-, N-diarylmethyl- and N-trityl-benzotriazole, and of N-[bis-(4-methoxyphenyl)methyl]- and N-trityl-5,6-dimethylbenzotriazole under nitrogen have been investigated. In all these cases, the N-1 isomer predominates over the N-2 isomer at thermodynamic equilibrium, to an extent which depends on the steric bulk of the N-substituent. The rate of attainment of equilibrium depends on the electronic effects of the substituents, both in the benzotriazole ring and in the migrating group. These results, in conjunction with a cross-over experiment, support a mechanism involving a heterolytic N–C bond cleavage followed by an intermolecular rearrangement.

1H and 13 NMR study of the structure of 3‐N‐(4‐ and 5‐benzimidazolyl or benztriazolyl)amino derivatives of prop‐2‐enoic acid in the liquid and solid states

AbstractBenzimidazole‐ and benzotriazole‐amino derivatives of prop‐2‐enoic acid were studied by 1H NMR spectroscopy in the liquid state and by 13C NMR spectroscopy in the liquid and solid states. The spectra shows tautomerism of the benzimidazole and benzotriazole rings, E‐Z isomerism of the double bond of the propenoic acid substituent and the conformation around the amino NHCH bond. The formation of an intramolecular hydrogen bond between the amino proton and the COOR group of propenoic acid is discussed. The structures of the derivatives are presented on the basis of the 13C CP‐MAS NMR spectra in the solid state.