288-94-8Relevant academic research and scientific papers
Mild and Catalyst-Free Microwave-Assisted Synthesis of 4,6-Disubstituted 2-Methylthiopyrimidines - Exploiting Tetrazole as an Efficient Leaving Group
Thomann, Andreas,Eberhard, Jens,Allegretta, Giuseppe,Empting, Martin,Hartmann, Rolf W.
, p. 2606 - 2610 (2015)
Typically, 4,6-disubstituted 2-thiomethylpyrimidines are synthesized starting from 4,6-dichloro-2-thiomethylpyrimidine or an amino-substituted precursor. However, these reactions take several hours up to days and require multiple steps. Herein, we report a novel, easy, and quick-to-prepare synthetic intermediate, namely 2-(methylthio)-4,6-di(1H-tetrazol-1-yl)pyrimidine, for the synthesis of these interesting target compounds. The intermediate can be transformed within minutes into desired substituted pyrimidines under mild conditions with moderate to excellent yields. The reaction can be conducted in an automated microwave system, at room temperature or by conventional heating. Furthermore, we demonstrate the robustness of the method in a one-pot procedure.
Thermodynamic properties and tautomerism of tetrazole
Kabo, G. J.,Kozyro, A. A.,Krasulin, A. P.,Sevruk, V. M.,Ivashkevich, L. S.
, p. 485 - 493 (1993)
The results of a study of tetrazole in different phase states are given.The heat capacity of crystalline tetrazole was measured by vacuum adiabatic calorimetry (T = 5 K to 320 K) and by the triple-heat-bridge method (T = 320 K to 400 K).The fusion properties: Tfus = (430 +/- 1) K and ΔfusHm deg = (18.0 +/- 0.5) kJ * mol-1 were obtained by the latter method.The Cp.m = f(T) curve shows a small anomaly at temperatures from 230 to 245 K, connected with a reversible solid-to-solid transition: ΔtrsHm = (14.0 +/- 1.0) J * mol-1 and ΔtrsSm = (0.060 +/-0.004) J * K-1 * mol-1.The value of ΔfGm deg(cr. 298.15 K) = (363.16 +/- 0.91) kJ * mol-1 was found on the basis of our own and literature results.The sublimation enthalpy was directly determined by heat-conduction differential microcalorimetry: ΔsubHm deg(353 K) = (88.16 +/- 0.48) kJ * mol-1.The saturated vapour pressure of crystalline tetrazole was measured by the integral-effusion-Knudsen method from 333 K to 404 K: ln(p/Pa) = (31.148 +/- 0.458)-(10560 +/- 168)(K/T) and molar enthalpy of sublimation was calculated ΔsubHm deg(369 K) = (87.80 +/- 1.40) kJ * mol-1.From these results a weight-averaged molar enthalpy of sublimation ΔsubHm deg(350 K) = (88.25 +/- 0.45) kJ * mol-1 was calculated and the conventional molar entropy of gaseous tetrazole Sm deg(g, 350 K) = (274.07 +/- 1.45) J * K-1 * mol-1 was found.The ideal-gas entropy of tetrazole was calculated by a statistical-mechanical method from molecular and spectral quantities.The calculated entropy Sm deg(g, 350 K) = 277.52 J * K-1 * mol-1 is in satisfactory accordance with the experimental value.So, our thermodynamic investigation shows that tetrazole in the gas phase exists most probably as molecules with a single configuration (without a probable tautomerism 1-H = 2-H).Thermodynamic functions of tetrazole in the solid state (T = 0 to 400 K) and in the ideal-gas state (T = 100 K to 1000 K) were calculated and tabulated.The molar values Cp.m deg, Δ0TSm deg, Δ0THm deg/T, and Φm deg of crystalline and gaseous tetrazole at the temperature 298.15 K are, respectively: (76.52 +/- 0.31) and 52.37; 96.40 +/- 0.41 and 267.12; 45.60 +/- 0.18 and 37.77; and 50.80 +/- 0.45 and 229.35) J * K-1 * mol-1.
Evidence of Ligand Elasticity Occurring in Temperature-, Light-, and Pressure-Induced Spin Crossover in 1D Coordination Polymers [Fe(3ditz)3]X2 (X = ClO4–, BF4–)
Weselski, Marek,Ksi??ek, Maria,Kusz, Joachim,Bia?ońska, Agata,Paliwoda, Damian,Hanfland, Michael,Rudolf, Miko?aj F.,Ciunik, Zbigniew,Bronisz, Robert
, p. 1171 - 1179 (2017)
The complexes [M(3ditz)3]X2 [X = ClO4–, M = FeII (1), ZnII (2); X = BF4–, M = FeII (3), ZnII (4); 3ditz = 1,3-di(tetrazol-1-yl)propane] were prepared. Disordering of the propylene chain in 3ditz is not affected by thermally induced spin crossover in 1 (T1/2↓ = 149 K, T1/2↑ = 150 K) and 3 (T1/2↓ = 158, T1/2↑ = 161 K). Low-spin to high-spin (LS→HS) switching triggered by laser-light irradiation (520 nm) also does not influence the disordering of the ligand, leading to restoration of the initial HS phase. Pressurization of crystals results in a reduction of the Fe–N distances by about 0.19 ?, which indicates practically complete spin crossover (SCO). Also, in this case, the disordering of the ligand remains unchanged, although thermally and pressure-induced SCO is accompanied by different changes of 3ditz molecules. Upon thermally induced SCO, perturbation resulting from the reduction of the Fe–N distances is accompanied by a slight elongation of the bridging ligand. In contrast, in the range 0.25–0.55 GPa, the pressure-induced SCO is associated with shrinkage of the 3ditz molecule. Further elevation of pressure results in the inversion of structural changes and – similar to temperature-induced spin crossover – a slight elongation of the ligand molecule takes place.
Synthesis and Characterization of Sodium 5-Chlorotetrazolate Dihydrate by Chlorination of 1H-Tetrazole
Wang, Xiaojun,Liu, Jiping,Wang, Dong,Bi, Xiaolu,Zhao, Wei
, p. 631 - 635 (2015)
A convenient, simple work-up procedure and low-cost chlorination method was developed to prepare sodium 5-chlorotetrazolate dihydrate by chlorination of self-prepared 1H-tetrazole with sodium hypochlorite solution. Several organic extracting solvents and factors (raw material ratio, reaction temperature, and reaction time) were investigated to optimize the operating conditions of the chlorination procedure. These products were characterized by 1H and 13C NMR spectroscopy, vibrational spectroscopy (IR), mass spectroscopy (MS), and single-crystal X-ray diffraction. In addition, the thermal behaviors of the resulting sodium 5-chlorotetrazolate dihydrate and sodium tetrazolate monohydrate were investigated and compared by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The results indicated that the optimum chlorination conditions were a stoichiometric raw materials ratio of 1:12:12 (1H-tetralzole: sodium hypochlorite solution : acetic acid solution), a reaction temperature of 55°C, a reaction time of 6 h, affording a 92.76% yield; moreover, acetone was determined to be the best extraction solvent in terms of yield and toxicity. Crystal data: sodium tetrazolate, orthorhombic, Pmc2(1), a = 5.847(4), b = 5.605(3), c = 6.387(4) ?, V = 209.3(2) ?3, Z = 2, ρ = 1.746 Mg·m-3; sodium 5-chlorotetrazolate, orthorhombic, Pnma, a = 6.8611(19), b = 6.9243(19), c = 12.281(4) ?, V = 583.5(3) ?3, Z = 8, ρ = 1.850 Mg·m-3. Sodium tetrazolate has a melting point at 275.97°C and an exothermic decomposition peak at 319.45°C, whereas sodium 5-chlorotetrazolate shows only a sharp exothermic peak at 237.33°C due to violent decomposition without melting.
SNAr azidation of phenolic functions utilizing diphenyl phosphorazidate
Ishihara, Kotaro,Shioiri, Takayuki,Matsugi, Masato
supporting information, (2019/12/27)
A useful method for the synthesis of aryl azides via SNAr reaction of phenol derivatives using diphenyl phosphorazidate (DPPA) as an azidation reagent was developed. Various phenol derivatives bearing electron-withdrawing groups were converted into the corresponding aryl azides in a single step. This method is easy to perform and enables the preparation of aryl azides without the use of explosive azide sources.
2-Methyl-substituted monotetrazoles in copper(ii) perchlorate complexes: manipulating coordination chemistry and derived energetic properties
Zeisel, Lukas,Szimhardt, Norbert,Wurzenberger, Maximilian H. H.,Klap?tke, Thomas M.,Stierstorfer, J?rg
supporting information, p. 609 - 616 (2019/01/10)
A proposed correlation between coordination chemistry and deduced energetic properties (thermal behaviour, and sensitivities towards mechanical and optical stimuli) of copper(ii) complexes is investigated. Starting from a system comprising Cu(ClO4)2 and either of the ligands 2-methyl-5-aminotetrazole (1, 2-MAT) or 2-methyl-5H-tetrazole (2, 2-MTZ), typically altered parameters like the metal(ii) centre, ligand, or counterion were predefined. Instead, solely slight changes in ligand concentration and the solvent system were implemented in order to provide an insight into structure-property relationships of energetic coordination compounds (ECC) of this type. As a result, five highly energetic complexes [Cu(H2O)2(2-MAT)4](ClO4)2·H2O (3), [Cu(H2O)2(2-MAT)4](ClO4)2 (4), [Cu(H2O)2(2-MAT)4](ClO4)2·2 2-MAT (5), [Cu(ClO4)2(H2O)2(2-MAT)2] (6), and [Cu(H2O)2(2-MTZ)4](ClO4)2 (7) were synthesized and, except for 5, elaborately characterized. Besides structural elucidation via X-ray diffraction, NIR-spectroscopy, differential thermal analysis (DTA), standard sensitivity measurements (impact, friction, and electrostatic discharge), UV/vis-spectroscopy, and optical initiation experiments were conducted to deduce a precise relationship between coordination chemistry and the consequential energetic characteristics of these complexes.
Microwave alkylation of lithium tetrazolate
Müller, Danny,Knoll, Christian,Weinberger, Peter
, p. 131 - 137 (2017/01/17)
Abstract: N1-substituted tetrazoles are interesting ligands in transition metal coordination chemistry, especially in the field of spin crossover. Their synthesis is performed in most cases according to the Franke-synthesis, using a primary amine as reagent introducing the substitution pattern. To enhance flexibility in means of substrate scope, we developed a new protocol based on alkylation of lithium tetrazolate with alkyl bromides. The N1–N2 isomerism of the tetrazole during the alkylation was successfully suppressed by use of highly pure lithium tetrazolate and 30?vol.% aqueous ethanol as solvent, leading to pure N1-substituted products. The feasibility of this reaction was demonstrated by a selection of different substrates. Graphical abstract: [Figure not available: see fulltext.]
Efficient transformation of inactive nitriles into 5-substituted 1 H-tetrazoles using microwave irradiation and their applications
Yoneyama, Hiroki,Usami, Yoshihide,Komeda, Seiji,Harusawa, Shinya
, p. 1051 - 1059 (2013/05/09)
Efficient transformations of inactive nitriles into 5-substituted 1H-tetrazoles in DMF in a microwave reactor are described. The present method is applied to the synthesis of tetrazolato-bridged dinuclear platinum(II) complex and tetrazole C1-ribonucleoside phosphoramidite. Georg Thieme Verlag Stuttgart, New York.
Amine salt-catalyzed synthesis of 5-substituted 1H-tetrazoles from nitriles
Zhou, Yi,Yao, Cheng,Ni, Renjie,Yang, Gaowen
experimental part, p. 2624 - 2632 (2010/10/03)
The [3+2] cycloaddition reaction between sodium azide and various organic nitriles proceeds smoothly in the presence of amine salts as catalyst in dimethylformamide. The corresponding 5-substituted 1-H tetrazoles were obtained under mild condition in good to excellent yields. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file. Taylor & Francis Group, LLC.
MACROCYCLES AND THEIR USES
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, (2009/07/25)
The present application describes organic compounds that are useful for the treatment, prevention and/or amelioration of diseases
