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International audience; The functionalization of (R,R)-S,S '-di-tert-butylferrocene-1,1 '-disulfoxide by deprotolithiation-electrophilic trapping sequences was studied towards polysubstituted, enantiopure derivatives for which the properties were determined. While the 2,2 '-disubstituted ferrocene derivatives were obtained as expected, subsequent functionalization of the 2,2 '-di(phenylthio) and 2,2 '-bis(trimethylsilyl) derivatives occurred primarily at the 4- or 4,4 '-positions. This unusual regioselectivity was discussed in detail in light of pK(a) values and structural data. The less sterically hindered 2,2 '-difluorinated derivative yielded the expected 1,1 ',2,2 ',3,3 '-hexasubstituted ferrocenes by the deprotometallation-trapping sequence. Further functionalization proved possible, leading to early examples of 1,1 ',2,2 ',3,3 ',4,4 '-octa, nona and even decasubstituted ferrocenes. Some of the newly prepared ferrocene-1,1 '-disulfoxides were tested as ligands for enantioselective catalysis and their electrochemical properties were investigated.

Tetrazolium-5-aminides have been prepared by the tert-butylation of 5-aminotetrazole and its N-methyl derivatives by the t-BuOH/HClO4 system followed by the treatment of the tetrazolium salts by alkali. The mesoionic compounds have been found to show a higher reactivity of the exocyclic N atom in comparison with 5-aminotetrazoles. The compounds reacted with 1,2-dibromoethane and 5-(methylsulfonyl)-1-phenyl-1H-tetrazole with substitution of bromine and methylsulfonyl groups giving the corresponding tetrazolium salts or conjugate aminides. The obtained mesoionic tetrazoles have been characterized by elemental analysis, FTIR, NMR, and UV–vis spectroscopy, TGA/DSC analysis and for 1,3-di-tert-butyltetrazolium-5-aminide, its N,N’-ethylene-bridged bis-derivative and (1,3-di-tert-butyl-1H-tetrazol-3-ium-5-yl)(1-phenyl-1H-tetrazol-5-yl)amide by single crystal X-ray analysis. The structural and spectral features of the tetrazolium-5-aminides are discussed by using quantum-chemical calculations.

International audience; Ferrocenesulfonyl fluorides represent a new subfamily of metallocenes barely explored. Here, we describe how the use of deprotolithiation-electrophilic trapping sequences and 'halogen dance' reactions can afford up to 1,2,3,4,5-hetero pentasubstituted derivatives. While the orthogonal reactivity of ferrocenesulfonyl fluorides was demonstrated in a variety of transformations, SuFEx chemistry afforded various sulfur-based ferrocene derivatives. The electrochemical behaviour of many polysubstituted derivatives was studied and discussed as well as weak interactions identified in the solid state.

International audience; Five protocols were first compared for the copper-catalyzed C-N bond formation between 7-azaindole and aryl/heteroaryl iodides/bromides. The 1-arylated 7-azaindoles thus obtained were subjected to deprotometalation-iodolysis sequences using lithium 2,2,6,6-tetramethylpiperidide as the base and the corresponding zinc diamide as an in situ trap. The reactivity of the substrate was discussed in light of the calculated atomic charges and the pK(a) values. The behavior of the 1-arylated 7-azaindoles in direct iodination was then studied, and the results explained by considering the HOMO orbital coefficients and the atomic charges. Finally, some of the iodides generated, generally original, were involved in the N-arylation of indole. While crystallographic data were collected for fifteen of the synthesized compounds, biological properties (antimicrobial, antifungal and antioxidant activity) were evaluated for others.

2-(1H-Tetrazol-1-yl)thiazole (tth), prepared by heterocyclization of 2-aminothiazole with triethyl orthoformate and sodium azide, was found to react with copper(II) chloride in ethanol giving a mixture of [Cu(tth)2Cl2]n (1) and [Cu2(ethc)2Cl4]·2H2O (2), where ethc is ethyl thiazol-2-ylcarbamimidate. Formation of complex 2 with ethc ligand can be explained by tetrazole ring-opening reaction of tth followed by addition of ethanol to the intermediate N-(thiazol-2-yl)cyanamide (N-tca). This assumption was confirmed by isolation of complex 2 under interaction of N-tca with copper(II) chloride in ethanol. Transformation of the tetrazole ring was not observed under interaction of tth and copper(II) chloride in 1,2-dichloroethane/ethanol mixture, when 1 and [Cu2(tth)4Cl4] (3) were isolated. Ligand tth was found to react with copper(II) tetrafluoroborate and cobalt(II) chloride giving [Cu(tth)2(H2O)4](BF4)2 (4) and [Co(tth)2Cl2(H2O)2]·2tth (5), correspondingly. Molecular crystals of tth and complexes 1–5 were characterized by X-ray single crystal analysis. In the complexes, tth acts as a monodentate ligand coordinated via the tetrazole ring N4 atom.

A series of cupric chloride complexes with 1-methyl-5-R-tetrazole ligands, where R = NH2, t-Bu, Ph, MeS, CH CH2, MeSO2, were synthesized by interaction of CuCl2·2H2O with the above ligands LNH2, LtBu, LPh, LMeS, LVin, and LMeSO2, respectively. The obtained complexes [Cu(LNH2)3Cl2]·H2O (1), [Cu(LtBu)2Cl2] (2), [Cu(LPh)2Cl2] (3), [Cu(LMeS)2Cl2] (4), [Cu(LVin)Cl2]n (5), and [Cu(LMeSO2)(H2O)Cl2]n (6) were characterized by single crystal X-ray analysis. The effect of C5-substituent on coordination modes of tetrazole ligands and structural motifs of complexes was observed. Complexes 1–4 are mononuclear, with the tetrazole ring N4 coordination. Complex 5 presents 1D coordination polymer, formed at the expense of triple bridge between two neighboring copper(II) cations (double chlorido bridge and the tetrazole ring N3,N4-bridge). In 6, being also 1D coordination polymer, coordination chains are composed of alternating Cu(LMeSO2)2 and Cu(H2O)2 fragments linked by double chlorido bridges. Ligand LMeSO2 shows N3 coordination, being rare among 1,5-disubstituted tetrazoles. The influence of the nature of C5 substituents on coordination features of the obtained complexes is discussed by using quantum-chemical calculations of the electronic structure and basicity of the ligands.

International audience; Few studies have been reported on the synthesis of ferrocenesulfonates up to now. Here, we describe the use of ortho-deprotometalation and "halogen dance" reactions to easily reach original derivatives. Further functionalizations using cross-coupling and metal/halogen exchange were also performed from iodinated derivatives. Finally, while the electrochemical properties of selected ferrocenesulfonates were evaluated and compared with the corresponding sulfonamide derivatives, halogen bonds were observed at the solid state for iodinated derivatives of ferrocenesulfonates.

International audience; Despite the well-established pharmacological properties of aromatic sulfonamides and the interest of introducing ferrocene into drugs, ferrocene sulfonamides have scarcely been studied. General synthetic methods using lithium bases to perform sulfonamide-directed deprotolithiation or the "halogen dance" reaction are here reported for the functionalization of N,N-dialkylferrocenesulfonamides toward various polysubstituted derivatives. Postfunctionalization of the ferrocenyl iodides by cross-coupling and lithium/iodine exchange reactions were also considered. Finally, the ligand behavior of new ferrocene phosphines in palladium-catalyzed coupling reactions was studied, and the reaction outcomes are viewed in light of DFT calculations.

Different 2-arylated oxazolo[4,5-b]pyrazines, obtained by palladium(II)-catalyzed domino reaction from 2,3-dichloropyrazine and the corresponding carboxamides, were functionalized by deprotometallation. Employing lithium 2,2,6,6-tetramethylpiperidine, in order to form a lithio derivative, and then trapping it by iodolysis, proved to be inefficient. However, the presence of a zinc-based in situ trap allowed most substrates to be functionalized. Deprotonation of the pyrazine ring was observed in the presence of tolyl and anisyl groups at the oxazole 2-position. In contrast, with chlorophenyl and thienyl groups in this 2-position, deprotonation rather occurred on these groups either competitively or exclusively. The regioselectivities were discussed in the light of calculated pK(a) values of the substrates in THF. Finally, in the case of 2-phenyloxazolo[4,5-b]pyrazine, we converted the mixture of 5- and 6-iodinated products into the corresponding 5,6-diiodide, which was further functionalized by a double Suzuki coupling.

Various aromatic ketones were first functionalized next to the carbonyl function by deprotolithiation in the presence of a zinc salt followed by iodolysis. The outcome of the reactions was analyzed, and in particular their regioselectivity in the light of the calculated pKa values. The various halogenated ketones were next involved in copper-catalyzed twofold C-N bond formation in order to obtain fused systems based on 2-aminopyrimidines. Besides potential antibacterial effect, reached 2-aminobenzothiopyrano[4,3,2-de]quinazoline proved to inhibit PIM1 (IC50: 0.61 μM) and CDK2/cyclin A (IC50: 2.0 μM) kinases.

International audience; A series of methoxy- and fluoro-pyridines have been deprotometalated in tetrahydrofuran at room temperature by using a mixed lithium-zinc combination obtained from ZnCl2·TMEDA (TMEDA = N,N,N’,N’-tetramethylethylenediamine) and LiTMP (TMP = 2,2,6,6-tetramethylpiperidino) in a 1:3 ratio, and the metalated species intercepted by iodine. Efficient functionalization at the 3 position was observed from 4-methoxy, 2-methoxy, 2,6-dimethoxy, 2-fluoro and 2,6-difluoropyridine, and at the 4 position from 3-methoxy and 2,3-dimethoxypyridine. Interestingly, clean dideprotonation was noted from 3-fluoropyridine (at C2 and C4) and 2,6-difluoropyridine (at C3 and C5). The obtained regioselectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase (DFT B3LYP and G3MP2B3 levels) and in THF solution. In the case of methoxypyridines, the pKa values have also been calculated for complexes with LiCl and LiTMP

International audience; The ferrocene halogen "dance" has been deemed hardly controllable. Here, we describe the first efficient examples of this reaction. Conversion of 1-fluoro-2-iodo (or 1-chloro-2-iodo) to 1-fluoro-3-iodo (or 1-chloro-3-iodo) ferrocenes was ensured by suitably protecting the free 5 position.

International audience; Two methods were compared to convert ferrocene into N,N-diisopropylferrocenecarboxamide, N,N-diethylferrocenecarboxamide, N,N-dimethylferrocenecarboxamide, and (4-morphohnocarbonyl)ferrocene, namely, deprotometalation followed by trapping using dialkylcarbamoyl chlorides and amide formation from the intermediate carboxylic acid. The four ferrocene-carboxamides were functionalized at C-2; in the case of the less hindered and more sensitive amides, recourse to a mixed lithium-zinc 2,2,6,6-tetramethylpiperidino-based base allowed us to "achieve the reactions. Halogen migration using lithium amides was next optimized. Whereas it appeared impossible to isolate the less hindered 3-iodoferrocenecarboxamides, 3-iodo-N,N-diisopropylferrocenecarboxamide proved stable and was converted to new 1,3-disubstituted ferrocenes by Suzuki coupling or amide reduction. DFT calculations were used to rationalize the results obtained.

4-Nitro-1,2,3-triazole was found to react with tert-butanol in concentrated sulfuric acid to yield 1-tert-butyl-4-nitro-1,2,3-triazole as the only reaction product, whereas tert-butylation and tritylation of 4-nitro-1,2,3-triazole in presence of catalytic amount of sulfuric acid in benzene was found to provide mixtures of isomeric 1- and 2-alkyl-4-nitro-1,2,3-triazoles with predominance of N2-alkylated products. A new methodology for preparation of 1-alkyl-5-nitro-1,2,3-triazoles from 1-tert-butyl-4-nitro-1,2,3-triazole via exhaustive alkylation followed by removal of tert-butyl group from intermediate triazolium salts was demonstrated by the example of preparation of 1-methyl-5-nitro-1,2,3-triazole.

The behavior of amino- and mercapto-1,2,4-triazoles in a t-BuOH–HClO4 system has been examined. Under the investigated conditions monoalkylation of 3-amino-1,2,4-triazole proceeds at the endocyclic N1 atoms whereas 1,2,4-triazole-3-thiol undergoes S-tert-butylation. Exhaustive alkylation of the above mentioned triazoles results in di-tert-butyl substituted derivatives, which give 1,3-disubstituted triazoles under the action of base. 4-Amino-1,2,4-triazole undergoes alkylation on the amino group as well as on the endocyclic N1 atom giving a 1,4-disubstituted triazolium salt. An X-ray diffraction investigation of 5-tert-butylsulfanyl-1,2,4-triazole, 1-tert-butyl-3-tert-butylamino-1,2,4-triazol-4-ium, 1-tert-butyl-3-tert-butylsulfanyl-1,2,4-triazol-4-ium, and 1-tert-butyl-4-tert-butylamino-1,2,4-triazolium perchlorates was carried out.

Intramembrane complex formation processes of heptyl p-trifluoroacetylbenzoic ether with series of anions have been studied using reference ion technique. The influence of the ion exchanger nature and the ability of the anion to form intramolecular hydrogen bond on the values of formal complex formation constants have been elucidated. Theoretical studies of methyl p-trifluoroacetylbenzoic ether interactions with acetate and bromide taken as model substances were carried out using density functional theory B3LYP method.

The dinuclear nickel(II) complex [Ni 2 L(μ-ClO 4 )]ClO 4 , where L 2- represents a 24-membered macrocyclic bis(triamine-thiophenolate) ligand, reacts with 1-methyltetrazole-5-thiol and triethylamine to give the complex [Ni 2 L(μ-SCN 4 Me)]ClO 4 , which was subjected to metathesis with NaBPh 4 yielding [Ni 2 L(μ-SCN 4 Me)]BPh 4 . This new complex was characterized by elemental analysis, UV/Vis/NIR and IR spectroscopy. The structure of [Ni 2 L(μ-SCN 4 Me)]BPh 4 was determined by X-ray crystallography, showing the 1-methyltetrazole-5-thiolate ligand in an N(3),N(4)-bridging mode generating a bis(octahedral) N 3 Ni(μ-S) 2 (μ-SCN 4 Me)NiN 3 core. Quantum chemical calculations of the molecular electrostatic potential, natural population analysis and total energies of possible structures of [Ni 2 L(μ-SCN 4 Me)] + are in agreement with the structural data obtained. Temperature-dependent magnetic susceptibility measurements revealed that the Ni II ions in the dinuclear complex are weakly ferromagnetically coupled showing a coupling constant J of 19.5 cm -1 (H = -2JS 1 S 2 ).

The CH acidity of all possible N -methyl substituted nitrotriazoles as well as of some 4-substituted 1,2,3-triazoles and N -alkyl-4-nitro-1,2,3-triazoles in the gas phase and in THF and DMSO solution has been calculated with the density functional theory B3LYP method. Electronic effects of substituents on the CH acidity of 4-substituted 1,2,3-triazoles have been examined using linear free energy relationship (LFER) methodology. In order to investigate the relation between the CH acidity of the heterocycles and their ability to undergo electrophilic substitution involving C–H bond cleavage, we have studied the reaction of isomeric N -alkyl-4-nitro-1,2,3-triazoles (alkyl=methyl, ethyl, isopropyl and tert -butyl) with HgBr 2 in alkali solution. It was found that 1-isomers undergo mercuration readily, while mercuration of 2-substituted compounds do not occur under the same conditions, which is in agreement with the results of DFT calculations of the CH acidity of the compounds, showing that 2-isomers have considerably lower CH acidity than 1-isomers.

The influence of the nature of plasticizer in the membrane of an ion-selective electrode (ISE) on its selectivity to cations of more than 20 physiologically active amines (PAA) is studied. It is found that an increase in the basicity of the plasticizer leads to a sharp increase in the membrane selectivity to PAA cations with lower degrees of the substitution of the salt-forming nitrogen atom, and also to PAA cations with nonionic polar groups capable of forming hydrogen bonds with Lewis bases. PAA cations forming intermolecular hydrogen bonds are an exception. The effect of the nature of the ion exchanger on the selectivity to PAA cations is strongest when plasticizers with low basicity are used; the selectivity of membranes with plasticizers of high basicity does not depend on the nature of the ion exchanger. For ISEs based on the neutral carrier dibenzo-18-crown-6 (DB-18-C-6), the best selectivity to primary amine cations in comparison to secondary and tertiary ones is achieved using plasticizers with low basicity.

N-Substituted bis(tetrazol-5-yl)diazenes (substituents are 1-CH3 (3a), 1-Ph (3b), 2-CH3 (3c), and 2-tBu (3d)) were synthesized by oxidative coupling of corresponding 5-aminotetrazoles. All compounds were characterized with 1H and 13C NMR, IR- and UV-spectroscopy, and thermal analysis. Crystal and molecular structures of bis(1-phenyltetra- zol-5-yl)diazene (3b) and bis(2-tert-butyltetrazol-5-yl)diazene (3d) were determined by single crystal X-ray diffraction. Molecules of these compounds are trans-isomers in solid. According to X-Ray data, 3b molecule is S-trans-S-trans conformer, however 3d is S-cis-S-cis one. Quantum-chemical investigation of geometry and relative stability of cis- and trans-isomers and stable conformations of compounds 3a–d was carried out. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:24–35, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20574

The process of alkylation of 1-alkyl-substituted 4-nitro-1,2,3-triazoles with dimethyl and diethyl sulfates has been studied. The structures of the N,N’-dialkyl-C-nitro-1,2,3-triazolium alkylsulfates and perchlorates has been confirmed by IR, 1H and 13C NMR spectroscopy. Alkylation with an excess of dialkyl sulfate occurred regioselectively at N-3 with the formation of 1,3-dialkyl-4-nitro-1,2,3-triazolium salts, which is in agreement quantum-chemical calculations of the relative stability of the corresponding isomeric cations. The molecular and crystal structures of the first example of this type of salt – 1,3-diethyl-4-nitro-1,2,3-triazolium perchlorate – have been determined by X-ray crystallo-graphy. Nitrotriazolium salts with mixed alkyl substituents – 3-ethyl-1-methyl- and 1-ethyl-3-methyl-4-nitro-1,2,3-triazolium salts – have been synthesized an studied for the first time.

Quantum-chemical calculations of the standard enthalpies of formation in the gas phase of C-nitro-1,2,4-triazole and isomers of N-alkyl-C-nitro-1,2,4-triazoles (Alk = Me, Et, i-Pr, t-Bu) were carried out by the B3LYP method using equations for the isodesmic reactions and isomerization reactions. The relative Gibbs free energies of tautomers and isomers in aqueous solution were calculated. For the tautomers of C-nitro-1,2,4-triazole the structural indexes of aromaticity were estimated and the electron population density of the Natural Bond Orbital was analyzed. The relative stabilities of the described tautomers and isomers in the gas phase and in solutions were discussed on the basis of the results of the calculations.

Quantum-chemical calculations have been carried out on molecular electrostatic potentials, proton affinity in the gas phase, gas phase basicity, and pK BH+ values in aqueous solution for C-nitro- and N-alkyl-4(5)-nitro-1,2,3-triazoles, and the relative stability of the isomeric N-alkyl-4(5)-nitrotriazoles (alkyl = Me, Et, i-Pr, t-Bu) in the gas phase and in aqueous solution. For all the studied substances in the gas phase the 2H-tautomer and the N(2)-isomers were considerably more stable than the corresponding N(1) compounds, and the 3H-tautomer and N(3)-isomer were the least stable. In aqueous solution 1- and 3-isomers had close values of energies, but in the case of C-nitro-1,2,3-triazole the 1H form became even more stable than the 2H-form. It was established which ring nitrogen atoms of 1,2,3-triazoles are protonated in the gas phase and in solution. The obtained data correlate well with the results of experimental investigations on the alkylation of 1,2,3-triazoles in acidic and basic media and of the experimental investigation on the alkylation of C-nitro-1,2,3-triazoles with diethyl sulfate carried out in the present work.

The formation enthalpies of tautomeric forms of 1,2,3-triazole, 4(5)-nitro-1,2,3-triazole and isomeric N-alkyl-4(5)-nitro-1,2,3-triazoles (alkyl = methyl, ethyl, isopropyl and tert-butyl) have been calculated with the density functional theory B3LYP method by means of designed isolobal, isodesmic and isomerisation reactions. The experimental ideal-gas formation enthalpy of 2-methyl-4-nitro-1,2,3-triazole has been determined based on the formation enthalpy in the crystalline state and the sublimation enthalpy. The experimental value of formation enthalpy (228.7 ± 3.5 kJ mol−1) is in good agreement with the one obtained from reaction enthalpy calculations (233.5 kJ mol−1). The relative Gibbs energies for tautomeric forms of 1,2,3-triazole and 4(5)-nitro-1,2,3-triazole and isomeric N-alkyl-4(5)-nitro-1,2,3-triazoles in aqueous solution have also been calculated using the Conductor polarized continuum model (CPCM). The results of the calculations have been discussed concerning the relative stability of the titled compounds.

The crystal and molecular structures of 1-vinyl-5-amino-1 H -tetrazole (VAT) were determined by single crystal X-ray diffraction. The amino group lies in the plane of the tetrazole ring and valence angles around the N atom are close to 120°, the exocyclic C N amino bond being substantially shorter in comparison with “normal” C N bond. Natural bond orbital analysis was performed, using density functional theory B3LYP method, to explain the structural peculiarities of crystalline VAT. By using MO calculations, relative stability of all possible tautomeric forms of protonated VAT molecule was investigated.

International audience; Substituted azafluorenones were synthesized from dihalogeno diaryl ketones under palladium catalysis by combining, in auto-tandem processes, Suzuki coupling and intramolecular arylation reactions. Different dihalogenated diaryl ketones, prepared by sequential deprotocupration-aroylation, were identified as suitable substrates to this purpose. Conditions were identified to allow successful syntheses of several 6-/7-arylated 4-azafluorenones, 1-substituted 4-azafluorenones, 2-phenyl-3-azafluorenone and 4-phenyl-3-azafluorenone from 3-(bromobenzoyl)-2-chloropyridines, 3-benzoyl-4-bromo-2-chloropyridines, 4-benzoyl-2,5-dichloropyridine and 4-benzoyl-2,3-dichloropyridine, respectively. Some of the synthesized compounds exhibit interesting biological properties.

International audience; The metallation of aryl ketones was achieved by using LiTMP in the presence of ZnCl2 center dot TMEDA, as evidenced by subsequent interception with iodine or by a palladium-catalysed cross-coupling reaction. One of the synthesized iodo ketones has been further elaborated to reach derivatives of biological interest.

1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2](4+) (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N(4)-coordination, and two ligands L providing two tetrazole ring N(3),N(4) bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions. Complex 2 includes a linear trinuclear complex cation [Cu3L6(H2O)6](6+) (the S6 symmetry point group), in which neighbouring copper(ii) cations are linked by three ligands L via tetrazole ring N(3),N(4) bridges; central and terminal metal ions show octahedral CuN6 and CuN3O3 coordination cores, respectively. The temperature-dependent magnetic susceptibility measurements of complex 2 revealed that the copper(ii) ions were weakly ferromagnetically coupled showing a coupling constant J of 2.2 cm(-1) {H = -2J(S1S2 + S2S3)}. The quantum-chemical investigation of the electronic structure and basicity of ligand L was carried out.

International audience; 1-Aryl- and 2-aryl-1,2,3-triazoles were synthesized by N-arylation of the corresponding azoles using aryl iodides. The deprotometalations of 1-phenyl-1,2,3-triazole and -1,2,4-triazole were performed using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination and occurred at the most acidic site, affording by iodolysis the 5-substituted derivatives. Dideprotonation was noted from 1-(2-thienyl)-1,2,4-triazole by increasing the amount of base. From 2-phenyl-1,2,3-triazoles, and in particular from 2-(4-trifluoromethoxy)phenyl-1,2,3-triazole, reactions at the 4 position of the triazolyl, but also ortho to the triazolyl on the phenyl group, were observed. The results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method. 4-Iodo-2-phenyl-1,2,3-triazole and 4-iodo-2-(2-iodophenyl)-1,2,3-triazole were next involved in Suzuki coupling reactions to furnish the corresponding 4-arylated and 4,2’-diarylated derivatives. When evaluated for biological activities, the latter (which are resveratrol analogues) showed moderate antibacterial activity and promising antiproliferative effect against MDA-MB-231 cell line.

The data on synthesis, crystal structure, magnetic susceptibility and thermal properties of coordination compound of copper(II) chloride with 2-methyltetrazole (2mtet) of Cu(2mtet)2Cl2 composition are reported. The Cu atom environment forms an elongated octahedron, with two 2-methyltetrazole ligands (N4 bound) and two Cl atoms in the equatorial positions. Symmetry related 2-methyltetrazole ligand and Cl atom are in the axial positions. One of the two 2-methyltetrazole molecules of the asymmetric unit exhibits bridging properties being linked to two Cu atoms through two N atoms (i.e., N4 and N1) of the tetrazole ring, while the other ligand molecule is coordinated in monodentate fashion via one tetrazole N4 atom. The Cu-octahedra form dinuclear building bricks by sharing edges with equatorial and axial Cl atoms. These dinuclear units are linked together via bridging 2-methyltetrazole ligands to form infinite layers parallel to the ( 1 0 1 ¯ ) plane. Magnetic properties of Cu(2mtet)2Cl2 and the data of quantum-chemical calculations of molecular electrostatic potential and energies of hydronation of nitrogen atoms for 2mtet using B3LYP/6-31G* level of theory are in agreement with the structural data obtained.

Two new coordination complexes, Cu(datz)Cl2 and Cu(datz)2Cl2, where datz is 1,5-diaminotetrazole, have been obtained by the reaction of copper(II) chloride with datz. For one of them, Cu(datz)2Cl2, the crystal structure, magnetic susceptibility and thermal properties are reported. For the other compound only spectroscopic and thermal properties are presented. In Cu(datz)2Cl2 the Cu atoms were found to be octahedrally coordinated. Equatorial positions are occupied by two chloride anions and two tetrazole ligands via their N4 donor atoms. Surprisingly, the amino groups at the N1 atom of the tetrazole ring of nearby molecules are in axial positions. Each copper atom is linked with four others through the datz molecules to form 2D polymeric networks parallel to the yz plane. Magnetic properties of Cu(datz)2Cl2 and the data of quantum-chemical calculations of molecular electrostatic potential and energies of hydronation of nitrogen atoms for datz using MP2/6-31G* and B3LYP/6-31G* levels of theory are in agreement with the structural data obtained.

Calculations have been carried out of the total Mulliken charges on carbon and nitrogen atoms, the relative stability, and equilibrium populations of the s-cis(R) and s-trans(R) conformers of a series of 1-vinyl-5R-tetrazoles (R = H, Me, n-Bu, tert-Bu, Ph, NH2, I, CF3, NO2) by the ab initio MP2/6-31G** method. Out-of-plane structures correspond to the stable s-cis(R) conformer, and the deviation from planarity grows regularly with an increase in the bulk of the substituent. The proportion of s-trans(R) conformation increases in the same series and reaches 100% for R = tert-C4H9. The data of quantum-chemical calculations are in agreement with the results of investigations of the spatial structure of 1-vinyl-5R-tetrazoles by 1H and 13C NMR methods. Values of the total energies of the corresponding homodesmotic reactions were calculated to assess the effect of the nature of the substituent in position 5 of the tetrazole ring on the size of the conjugation energy in planar s-trans(R) conformations of the compounds investigated. The quantum-chemical calculations carried out show that the conjugation energy decreases regularly according to the increase in electron-withdrawing properties of the substituent in position 5 of the ring.

Study of interaction of NO and (NO)2 molecules with silver clusters has been carried out using the hybrid method S2LYP based on density functional theory (DFT). The role of cluster charge and site of adsorption on N–O stretch frequency, adsorption energy and geometry has been investigated. Four cluster models of different size have been used for simulation of (NO)2 adsorption on Ag{111} surface. The pronounced effect of N–N bond shortening in comparison with gaseous (NO)2 has been found due to adsorption of (NO)2 on silver cluster. This phenomenon is important as possible pathway of N–N bond formation in catalytic fragmentation of NO molecule. The calculations showed that the silver octamer is the best candidate for simulation of formation and fragmentation of (NO)2 on Ag{111} surface within the cluster model.

In the molecules of 5-amino-1-phenyltetrazole, C(7)H(7)N(5), (I), and 5-amino-1-(1-naphthyl)tetrazole, C(11)H(9)N(5), (II), the tetrazole rings and aryl fragments are not coplanar; corresponding dihedral angles are 50.58 (5) and 45.19 (7) degrees for the two independent molecules of (I), and 64.14 (5) degrees for (II). Intermolecular N-H.N hydrogen bonds between the amino groups and tetrazole N atoms are primarily responsible for formation of two-dimensional networks extending parallel to the bc plane in both compounds. The presence of the amino group has a distinct effect on the geometry of the tetrazole rings in each case.

The crystal and molecular structures of 1,5-diamino-1H-1,2,3,4-tetrazolium picrate (DATP) were determined by X-ray diffraction analysis. The tetrazolium cation in DATP has a structure with protonated N4 atom of the ring. Two amino groups in the cation are found to be rather different. The 5-amino group lies in the plane of the tetrazole ring and valence angles around the N atom are close to 1208, which indicates sp 2 hybridization of atomic orbital of the nitrogen atom. In contrast, valence angles around the N atom of the 1-amino group are close to tetrahedral angle, which suggests sp 3 hybridization. The exocyclic C– N bond in the cation is substantially shorter than that in 1,5-diaminotetrazole. The obtained results indicate a conjugation between the p-system of the tetrazole ring and the 5-amino group. The results of ab initio calculations of electronic structure and relative stability for various tautomeric forms of protonated 1,5-diaminotetrazole using MP2/6-31G* and B3LYP/6-31G* levels of theory are in a good agreement with X-ray data and show that there are differences in s-electron overlap populations for the C– N bonds in the cation in DATP, while p-electrons are delocalized. q 2003 Elsevier Science B.V. All rights reserved.

In the indazole series, the title reaction leads to ring opening of the heterocycle in general.

1-Aryl-1H-benzotriazoles and -1H-indazoles were synthesized, and their deproto-metallation using the base prepared by mixing LiTMP with ZnCl2·TMEDA (1/3 equiv.) was studied. In the indazole series, reactions occurring at the 3 position were followed by ring opening, and functionalization of the substrate was only found possible (on the sulfur ring) using 2-thienyl as aryl group. In the benzotriazole series, either mono- or bis-deprotonation (depending on the amount of base employed) was achieved with phenyl, 4-methoxyphenyl and 2-thienyl as aryl group, and bis-deprotonation in the case of 4-chlorophenyl and 4-trifluoromethylphenyl. The experimental results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method.

International audience; 2-Substituted quinolines were synthesized, and their deproto-metallation using the bases prepared by mixing LiTMP with either ZnCl2*TMEDA (1/3 equiv) or CuCl (1/2 equiv) was studied. With phenyl and 2-naphthyl substituents, the reaction occurred at the 8 position of the quinoline ring, affording the corresponding iodo derivatives or 2-chlorophenyl ketones using the lithium-zinc or the lithium-copper combination, respectively. With a 4-anisyl substituent, a dideprotonation at the 8 and 3' position was noted using the lithium-zinc base. With 3-pyridyl, 2-furyl and 2-thienyl substituents, the reaction took place on the subtituent, at a position adjacent to its heteroatom. 2-Chlorophenyl 2-phenyl-8-quinolyl ketone could be cyclized under palladium catalysis. The experimental results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method.

4-Nitro-1,2,3-triazole was found to react with tert-butanol in concentrated sulfuric acid to yield 1-tert-butyl-4-nitro-1,2,3-triazole as the only reaction product, whereas tert-butylation and tritylation of 4-nitro-1,2,3-triazole in presence of catalytic amount of sulfuric acid in benzene was found to provide mixtures of isomeric 1- and 2-alkyl-4-nitro-1,2,3-triazoles with predominance of N2-alkylated products. A new methodology for preparation of 1-alkyl-5-nitro-1,2,3-triazoles from 1-tert-butyl-4-nitro-1,2,3-triazole via exhaustive alkylation followed by removal of tert-butyl group from intermediate triazolium salts was demonstrated by the example of preparation of 1-methyl-5-nitro-1,2,3-triazole.

International audience; A no. of substituted biaryls, arylpyridines, arylpyrimidines and arylquinolines was prepd. by coupling reactions; deprotonation-iodination with a mixed lithium/zinc-TMP base gives the corresponding iodides. The obtained exptl. results on acidity are compared with calcd. values of Gibbs energies of deprotonation at different positions of the considered biaryl and arylheterocyclic systems. With the aim of synthesizing biaryl compds., several arom. iodides were prepd. by the deprotonative metalation of methoxybenzenes, 3-substituted naphthalenes, isoquinoline, and methoxypyridines by using a mixed lithium/zinc-TMP (TMP = 2,2,6,6-tetramethylpiperidino) base and subsequent iodolysis. The halides thus obtained, as well as com. compds., were cross-coupled under palladium catalysis (e.g., Suzuki coupling with 2,4-dimethoxy-5-pyrimidylboronic acid) to afford various representative biaryl compds. Deprotometalation of the latter compds. was performed by using the lithium/zinc-TMP base and evaluated by subsequent iodolysis. The outcome of these reactions has been discussed in light of the CH acidities of these substrates, as detd. in THF soln. by using the DFT B3LYP method. Except for in the presence of decidedly lower pKa values, the regioselectivities of the deprotometalation reactions tend to be governed by nearby coordinating atoms rather than by site acidities. In particular, azine and diazine nitrogen atoms have been shown to be efficient in inducing the reactions with the lithium/zinc-TMP base at adjacent sites (e.g., by using 1-(2-methoxyphenyl)isoquinoline, 4-(2,5-dimethoxyphenyl)-3-methoxypyridine, or 5-(2,5-dimethoxyphenyl)-2,4-dimethoxypyrimidine as the substrate), a behavior that has already been obsd. upon treatment with lithium amides under kinetic conditions. Finally, the iodinated biaryl derivs. were involved in palladium-catalyzed reactions. [on SciFinder(R)]

In the crystal structure of the title compound, [Cu(3)Cl(6)(C(4)H(6)N(4))(4)](n), there are three Cu atoms, six Cl atoms and four 2-allyltetrazole ligands in the asymmetric unit. The polyhedron of one Cu atom adopts a flattened octahedral geometry, with two 2-allyltetrazole ligands in the axial positions [Cu-N4 = 1.990 (2) and 1.991 (2) A] and four Cl atoms in the equatorial positions [Cu-Cl = 2.4331 (9)-2.5426 (9) A]. The polyhedra of the other two Cu atoms have a square-pyramidal geometry, with three basal sites occupied by Cl atoms [Cu-Cl = 2.2487 (9)-2.3163 (8) and 2.2569 (9)-2.3034 (9) A] and one basal site occupied by a 2-allyltetrazole ligand [Cu-N4 = 2.028 (2) and 2.013 (2) A]. A Cl atom lies in the apical position of either pyramid [Cu-Cl = 2.8360 (10) and 2.8046 (9) A]. The possibility of including the tetrazole N3 atoms in the coordination sphere of the two Cu atoms is discussed. Neighbouring copper polyhedra share their edges with Cl atoms to form one-dimensional polymeric chains running along the a axis.

International audience; A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method.