- Self-assembly of novel manganese (II) compounds based on bifunctional-group ligands: Synthesis, structures, and magnetic properties
-
Four manganese (II) compounds are obtained by the reaction of manganese salts, triazole-derivatives and auxiliary reagents in aqueous solution or mix-solvents by routine or hydrothermal reactions. X-ray crystal structure analyses reveal that a neutral 0D compound [Mn(Hmctrz)2(H2O)2] (1) (H2mctrz = 1H-1,2,4-triazole-3-carboxylic acid) displays a centro-symmetric mononuclear octahedral entity with two Hmctrz? anions and two water molecules; two neutral 2D clusters [Mn(Hdctrz)(H2O)2]n (2) (H3dctrz = 1H-1,2,4-triazole-3,5-dicarboxylic acid) and [Mn2(pbtrz)(btca)]n·4nH2O (3) (pbtrz = 1,3-bis(1,2,4-triazol-1-yl)-propane&H4btca = benzene-1,2,4,5-tetracarboxylic acid) possess layer structures with Hdctrz2? linkers (2) and Mn(II)-pbtrz-Mn(II) building blocks periodically extended by μ-btca4? connectors (3); [Mn(pbtrz)]n·nOAc·nOH (4) shows a 3D diamond-shaped cationic framework with the anion void volume of 49.2%. Nitrogenous bases are used as the auxiliary ligand in compound 3 and the temple ligand in compounds 1, 2, and 4. Compounds 1–4 show antiferromagnetic coupling that has been fitted by different models with the molecular field approximate with D = ? 0.129(1) cm?1 for 1, J = ? 0.354(4) cm?1 for 2 and J = ? 0.696(6) cm?1 for 3, respectively. The magnetic differences can be related to different superexchange interactions transmitted by the crystal lattice and/or the zero field splitting (ZFS) of the 6A1g single-ion states of 1 and the syn-anti-COO? of 2 as well as the mixed magnetic bridges of μ1-O and μ-pbtrz-μ-COO? of 3.
- Yan, Juan-zhi,Lu, Li-ping,Zhu, Miao-li,Feng, Si-si
-
-
Read Online
- Triazoles as T2-Exchange Magnetic Resonance Imaging Contrast Agents for the Detection of Nitrilase Activity
-
We characterized the T2-exchange (T2ex) magnetic resonance imaging (MRI) contrast of azole protons that have large chemical shifts from the water proton resonance as a function of pH, temperature, and chemical modification. Our results showed that 1,2,4-triazoles could be tuned into excellent diamagnetic T2ex contrast agents, with an optimal exchange-based relaxivity r2ex of 0.10 s?1 mm?1 at physiological pH and B0=9.4 T. A fit of r2ex data to the Swift–Connick equation indicated that imino proton exchange of triazoles is dominated by a base-catalyzed process at higher pH values and an acid-catalyzed process at lower pH. The magnitude of r2ex was also found to be heavily dependent on chemical modifications, that is, enhanced by electron-donating groups, such as amines and methyls, or by intramolecular hydrogen bonding between the imino proton and the carboxyl, and weakened by electron-withdrawing groups like bromo, cyano, and nitro. In light of these findings, we applied T2ex MRI to assess the activity of nitrilase, an enzyme catalyzing the hydrolysis of 1,2,4-triazole-3-carbonitrile to 1,2,4-triazole-3-carboxylic acid, resulting in the enhancement of R2ex. Our findings suggest that 1,2,4-triazoles have potential to provide sensitive and tunable diagnostic probes for MRI.
- Zhang, Jia,Han, Zheng,Lu, Jiaqi,Li, Yuguo,Liao, Xuhe,van Zijl, Peter C.,Yang, Xing,Liu, Guanshu
-
-
Read Online
- Preparation method of 1-methyl-1H-1,2,4-triazole-3-methyl formate
-
The invention discloses a preparation method of 1-methyl-1H-1,2,4-triazole-3-methyl formate, belonging to the technical field of organic synthesis. The method comprises the following steps: with aminoguanidine bicarbonate and oxalic acid as raw materials, adding inorganic strong base for cyclization to obtain 3-aminotriazole-5-carboxylic acid; then subjecting 3-aminotriazole-5-carboxylic acid to reacting with sodium nitrite under an acidic condition to obtain diazonium salt; then subjecting diazonium salt to reacting with hypophosphorous acid to obtain 1,2,4-triazole-3-carboxylic acid; and then subjecting 1,2,4-triazole-3-carboxylic acid to reacting with a methylation reagent to obtain 1-methyl-1H-1,2,4-triazole-3-methyl formate. The method is simple to operate, raw materials are easy to obtain, and economic applicability of the method is high.
- -
-
Paragraph 0021-0036
(2021/09/01)
-
- Synthesis method of 1, 2, 4-triazole-3-formic acid
-
The invention provides a synthesis method of 1, 2, 4-triazole-3-formic acid, which comprises the following steps: reacting oxalylhydrazine and a formamidine salt in an organic solvent to obtain 1, 2,4-triazole-3-formyl-(N-phenyl) amine; then heating and hydrolyzing in an alkaline solution in the presence of a catalyst, and adjusting the pH value by using an acid to obtain 1, 2, 4-triazole-3-formic acid; the method has the advantages of accessible raw materials, mild reaction conditions, simple post-treatment and higher yield, avoids the explosion risk and environment-polluting stink substances in the traditional technique, obviously reduces the three wastes, and has industrialization prospects.
- -
-
Paragraph 0030; 0032; 0034; 0036; 0038; 0040; 0042; 0044
(2020/08/09)
-
- Chemoenzymatic method of 1,2,4-triazole nucleoside synthesis: Possibilities and limitations
-
Possibilities and limitations of chemoenzymatic synthesis of novel structural analogues of an antiviral preparation of Ribavirin (1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) were established. A synthesis of various amides of 1H-1,2,4-triazole-3-carboxylic acid and its 5-substituted analogues - potential substrates of purine nucleoside phosphorylase - has been described. Comparative efficiency of preparation methods of these amides, as well as the methods of introduction of functional groups to the C5 position of heterocyclic system, were investigated. Novel analogues of Ribavirin containing various substitutes in the carboxamide group were synthesized. A biotechnological method was developed for the preparation of 1-β-D-ribofuranozyl-1,2,4-triazole-3-carbonitryl, an intermediate in the synthesis of Viramidine, the modern analogue of Ribavirin.
- Konstantinova,Chudinov,Fateev,Matveev,Zhurilo,Shvets,Miroshnikov
-
-
- Study of direction of cyclization of 1-azolil-4-aryl/alkyl- thiosemicarbazides
-
On a four series of 1-azolil-4-aryl/alkyl-thiosemicabazides, a study on the influence of azole moiety on the capability for intramolecular cyclization and its direction was carried out. It was found that for 4-aryl/alkyl- thiosemicabazides with triazole, imidazole, or pyrrole moiety at N-1 nitrogen atom possible products were only s-triazoles, both in alkaline and acidic medium. Successful dehydrocyclization of 1-azolil-4-aryl/alkyl- thiosemicarbazides leading to a thiadiazole has been documented only for a series of 1-(4-methyl-1,2,3-thiadiazol-5-yl-carbonyl)-4-aryl/alkyl- thiosemicarbazides. It can be speculative that the determination of pK a value of oxygen atom of 1-azolil-4-aryl/alkyl-thiosemicarbazide can be a very valuable parameter in the prediction of the possibility of dehydrocyclization to form thiadiazole.
- Siwek, Agata,Wujec, Monika,Dobosz, Maria,Wawrzycka-Gorczyca, Irena
-
experimental part
p. 521 - 532
(2011/08/03)
-
- NOVEL PROCESSES FOR THE PREPARATION OF SUBSTITUTED PROPENONE DERIVATIVES
-
The present invention provides industrial and commercial processes for the preparation of 2-acyl-5-benzylfuran derivatives, 1,2,4-triazole-3-carboxylic acid ester derivatives and propenone derivatives having anti-HIV activities and usuful crystals thereof. wherein R1, R2 and R4 each is independently hydrogen or the like; A is CR6 or N; R6 is hydrogen or the like; Q is a protecting group; and L is a leaving group.
- -
-
-
- Towards the engineering of an orthogonal protein kinase/nucleotide triphosphate pair
-
Remolding protein/ligand interfaces has led to the development of new tools for the study of biological systems. Such methods allow one to engineer proteins with specificity for designed biological probes such as inhibitors, substrates or small molecule dimerizers. Previous work in our laboratory has resulted in engineered protein kinases with specificity for ATP analogs which are otherwise orthogonal ligands for wild type kinases. Kinase reactions of analog-sensitive mutant kinases in cell lysates using γ32P labeled ATP analogs allow identification of the direct substrates of the sensitized kinase. As an extension of this methodology, we have designed and evaluated an ATP analog, N4 (benzyl) ribavirin triphosphate, which may be a suitable phosphodonor for a kinase that does not utilize ATP. Such a modification is likely to be necessary for in vivo kinase substrate labeling experiments where competitive phosphodonors are present in high concentrations. (C) 2000 Elsevier Science Ltd.
- Ulrich, Scott M,Buzko, Oleksandr,Shah, Kavita,Shokat, Kevan M
-
p. 9495 - 9502
(2007/10/03)
-
- ENZYMATIC PREPARATIONS AND REGIOCHEMICAL PROPERTIES OF SOME NEW ADP-RIBOSYLATED 1,2,4-TRIAZOLES
-
NAD nucleosidase-catalysed trans-ADP-ribosylation has been investigated for some 1,2,4-triazole bases.The unsubstituted base 1 provided N4-ribosylated triazoles (14 and 9), whereas 3-substituted (amino, chloro, mercapto, and carbamoyl)triazoles 2-4 and 6 underwent a regiospecific N1-ribosylation to produce the corresponding triazole adenine dinucleotides 10-13 in a good or moderate yield.Dinucleotide structures and the site of ribosylation were verified by 1H and 15N NMR spectrometries.The 3-carbamoyltriazole dinucleotide 13 can be a useful intermediate on the road to the antiviral agent, ribavirin, 18.
- Tono-oka, Shuichi,Azuma, Ichiro
-
p. 297 - 300
(2007/10/02)
-