Cyclocondensation of α,Β-unsaturated ketones with 3-amino-1,2,4-triazole

Dihydro-1,2,4-triazolo[1,5-a]pyrimidine derivatives were obtained by condensation of 3-amino-1,2,4-triazole with 1,3-diaryl-1-propen-3-ones. The structure of 5-phenyl-7-(4-methylphenyl)-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine was established by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 229–233, February, 1988.     

Recyclization of Condensed Carbethoxypyrimidines Accompanied by Substitution of a Carbon Atom into the Heterocycle

Condensation in ethanol of ethyl ethoxymethyleneacetoacetate with systems containing an amidine fragment (substituted 3-aminopyrazoles and 3-amino-1,2,4-triazole) gave 6-carbethoxy-7-methylpyrazolo[1,5-a]pyrimidines. Addition of base to solutions of the obtained bicyclic carbethoxy derivatives in the course of several minutes caused rearrangement to 6-acetyl-7-hydroxypyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-1,2,4-triazolo[1,5-a]pyrimidine respectively. A more prolonged refluxing in 15% aqueous alcohol solution of base caused 6-carbethoxy-7-methyl-2-phenylpyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-2-phenylpyrazolo[1,5-a]pyrimidine to recyclize to 7-methylpyrazolo[1,5-a]pyrimidine.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 569–576, April, 2005.     

On triazoles XXIII [1]. The reaction of 5-amino-1,2,4-triazoles with thiacyclohexane β-oxo esters [2]

Six novel isomeric ring systems, namely the thiopyrano[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,4-e]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,4-d]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[4,3-e]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidine and the thiopyrano[2,3-e]-1,2,4-triazolo[1,5-a]pyrimidine were synthesised. Spectroscopical evidence was given for the structure of compounds obtained.     

Carbocycle annelated 1,2,4-triazolo[1,5-α]pyrimidines

Reaction of 3-amino-1,2,4-triazole with mono- and dibenzalcycloalkanones gives 4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidines annelated by five-, six-, or seven-membered carbocycles. They can be dehydrogenated to the corresponding heteraromatics. The spectra-luminescent properties of the compounds obtained are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 105–108, January, 1991.     

含肟醚的新型三唑并嘧啶衍生物的合成及除草活性研究

2-巯基-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶(6)与氯乙醛或氯丙酮反应生成5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶-2-硫丙酮(硫乙醛) (7). 中间体7与O-烷基(芳基)羟胺(5)反应得到目标化合物1-(5,7-二甲基-1,2,4三唑[1,5-a]嘧啶-2-硫)乙醛-O-烷基肟醚(9), 2-(5,7-二甲基-1,2,4三唑[1,5-a]嘧啶-2-硫)丙酮O-烷基肟醚(10). 初步生物活性测试结果表明部分化合物具有较好的除草活性.     

Imine-enamine tautomerism of dihydroazolopyrimidines 5. Steric effects and the tautomeric equilibrium for dihydro-1,2,4-triazolo[1,5-a]pyrimidines

The reaction of 3-amino-1,2,4-triazole with -dimethylaminopropiophenones or unsaturated ketones gives 5,7-disubstituted 4,7(6,7)-dihydro-1,2,4-triazolo[1,5-a]pyrimidines. An increase in the bulk of the substituent at C₍₇₎ in the bicyclic system leads to relative stabilization of the enamine tautomer of these compounds. An x-ray diffraction structural analysis of 7-tert-butyl-5-(4-methoxyphenyl)-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine showed that the introduction of a tert-butyl group into the dihydropyrimidine ring leads to significant loss of planarity of this system.For Communication 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1357–1363, October, 1993.     

Three component condensation of 3-amino-1,2,4-triazole with carbonyl compounds. A new synthesis of 1,2,4-triazolo[1,5-a]pyrimidines

Three component condensation of 3-amino-1,2,4-triazole with an aromatic aldehyde and ketone gives 1,2,4-triazolo[1,5-a]-pyrimidines. An x-ray structural investigation of 5-phenyl-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]benzo[h]quinazoline was undertaken in order to determine the course of this reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 481–485, April, 1993.     

Tautomerism of dihydro-1,2,4-triazolo[1,5-α]pyrimidines containing 2-hydroxy- and 4-dimethylaminoaryl substituents

We have studied the effect of structural factors and the nature of the solvent on the tautomeric composition of aromatic substituted dihydro-1,2,4-triazolo[1,5-a]pyrimidines. The kinetics of the tautomeric exchange of 5-(2-hydroxyphenyl)-7-phenyldihydro-1,2,4-triazolo[1,5-a]pyrimidines has also been investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 245–249, February, 1991.     

5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶双杂环衍生物的合成与生物活性

以2-巯基-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶为原料, 设计合成了17种含5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶环和1,2,4-三唑环的新型双杂环化合物, 结构经元素分析, MS, 1H NMR及13C NMR进行表征. 初步的生物活性测试表明, 部分化合物表现出较好的杀菌、除草活性.     

Blue organic light-emitting supramolecular microfibers: the self-assembly of a 1,2,4-triazolo[1,5-a]pyrimidine derivative

The design and synthesis of 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine-2-thioaceto-(2-fluorobenzyl) hydrazone (TPTH), which self-assembled into supramolecular microfibers with blue organic light-emitting properties, is reported. This is the first occurrence of the molecular self-assembly of 1,2,4-triazolo[1,5-a]pyrimidine derivatives.     

Molecular structure and tautomeric conversions of 5-(4-dimethylaminophenyl)-7-phenyl-6,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine

The x-ray structure is solved and the three-dimensional structure is analyzed for 5-(4-dimethylaminophenyl)-7phenyl-6,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine. Its reverse isomerization into the 4,7-dihydro species is studiedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 933–936, July, 1992.     

Imine-enamine tautomerism of dihydroazolopyrimidines. 3. 5-Aryl-substituted 4,7(6,7)-dihydro-1,2,4-triazolo[1,5-a]pyrimidines

5-Aryl-substituted 4,7(6,7)-dihydro-1,2,4-triazolo[1,5-a]pyrimidines were obtained by condensation of 3-amino-1,2,4-triazole with -dimethylaminopropiophenone hydrochlorides or crotophenone. The effect of steric and electronic factors on the position of the imine-enamine equilibrium in solutions of the synthesized substances is examined. 5-Phenyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyriniidine was subjected to x-ray diffraction analysis.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1539–1544, November, 1991.     

含噁二唑杂环取代的新型三唑并嘧啶衍生物的合成及其生物活性

2-肼羰基亚甲硫基-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶与二硫化碳在乙醇溶液中回流制得化合物2-(5-巯基-1,3,4-噁二唑-2-亚甲硫基)-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶, 后者在碱性环境中与卤化苄反应得到17种新型双杂环化合物. 对所得化合物结构均经元素分析, ¹H NMR和MS确认. 初步生物活性测试表明这些化合物具有一定的杀菌活性.     

Reaction of 3-formyl-2-methoxy-1,6-dioxaspiro[4.4]nonanes with 3-amino-1,2,4-triazole: synthesis of 2-(1,2,4-triazolo[1,5-a]pyrimid-6-yl)methylenetetrahydrofurans

The reaction of 3-formyl-2-methoxy-1,6-dioxaspiro[4.4]nonanes with 3-amino-1,2,4-triazole gives 2-(1,2,4-triazolo[1,5-a]pyrimid-6-yl)methylenetetrahydrofurans in 51–65% yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2004–2005, November, 1993.     

The effect of the azole ring on the conformational mobility of the dihydropyrimidine ring in 4,7-dihydroazolo[1,5-a]pyrimidines as judged from MNDO calculations

The equilibrium geometries of 4,7-dihydropyrazolo[1,5-a]pyrimidine, 4,7-dihydrotetrazolo [1,5-a]pyrimidine, 4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine, and 1,4-di-hydropyrimido [1,2-a]imidazole were calculated by the semiempirical quantum-chemical MNDO method. The dihydropyrimidine ring exhibits high conformational mobility in all of these compounds. The change in the energy occurring in the transition of the molecule to the boat conformation with an angle between the planar fragments of ±20° does not exceed 1 kcal mol^–1. The mobility of the dihydro ring increases as interactions between the -systems of the azole ring and the C=C double bond separated by an imino group and a methylene bridge decrease.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1418–1420, August, 1994.     

Synthesis, spectroscopic characterization, X-ray structure and DFT calculations of [Re(CO)3L2Cl] (L = 1,2,4-triazolo-[1,5-a]pyrimidine)

The paper presents a combined experimental and computational study of novel tricarbonyl complex – fac-[Re(CO)₃(tp)₂Cl] (tp = 1,2,4-triazolo-[1,5-a]pyrimidine). The compound has been characterized spectroscopically and structurally (by single-crystal X-ray diffraction). The absorption and emission spectra of the complex have been discussed on the basis of DFT and time-dependent (TD)DFT calculations.     

Synthesis of 5,7-Dimethyl-2-(5-Substituted-1,3,4-Oxadiazole-2-yl)- Methylenethio-1,2,4-Triazolo[1,5-a]Pyrimidines as Potential Fungicides

New challenging problems in plant protection technology have promoted research to discover more efficient pesticides. In recent years, many chemists have paid much attention to compounds bearing 1,2,4-triazolo [1,5-a] pyrimidine rings due to their broad spectrum of biological activities such as herbicidal and fungicidal effects1-7. Up to now, a great variety of these kinds of compounds have been synthesized, among which some commercially herbicides have been developed including metosulam, f…     

Platinum(IV) complexes with purine analogs. Studies of molecular structure and antiproliferative activity in vitro

A series of tetrachloride platinum(IV) compounds of the general formulae PtCl₄L₂, where L = 1,2,4-triazolo[1,5-a]pyrimidine (tp) (1), 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) (2), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) (3) and 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one (HmtpO) (4) have been prepared and characterized by thermal analysis, ¹H, ¹³C, ¹⁵N, ¹⁹⁵Pt NMR and IR spectroscopy. Spectral data suggest that the triazolopyrimidines act as a monodentate ligand via the nitrogen atom N(3). The preliminary assessments of antitumor properties of the four complexes were evaluated as in vitro antiproliferative activity against three cell lines: HL-60 human acute promyelocytic leukemia, SW707 rectal adenocarcinoma and HCV29T bladder cancer. PtCl₄(dbtp)₂ exhibits high cytotoxic activity against all human cell lines, whereas the other complexes are only moderately active.     

On triazoles XVIII. . an unexpected rearrangement observed during the reaction of 5-amino-1,2,4-triazoles with N-heterocyclic β-oxo-esters

In the course of the synthesis of pyrido[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine derivatives 3c representing a novel ring system an unexpected rearrangement of the intermediate enamines to yield 5 was observed. A mechanism of the formation of 5 was suggested. The isomeric pyrido[4,3-e]-1,2,4-triazolo[1,5-a]pyrimidine derivatives 4c containing also a new ring system were obtained, too. The structure of products obtained was proved with the help of their uv, cmr and X-ray spectra.     

含1,2,4-三唑-5-硫酮席夫碱的新型1,2,4-三唑并[1,5-a]嘧啶衍生物的合成及生物活性研究

以2-苄硫基-5-甲基-7-羟基-1,2,4-三唑并[1,5-a]嘧啶为原料,经醚化、肼解、成盐、关环和席夫碱反应合成了20个新型的含1,2,4-三唑-5-硫酮席夫碱的1,2,4-三唑并[1,5-a]嘧啶类化合物,通过IR,1H NMR,MS和元素分析对所合成的化合物进行了结构表征.初步生物活性测试结果表明,部分化合物表现出一定的抑菌或较好的抗烟草花叶病毒(TMV)活性.在500μg/mL浓度下,化合物6b,6f和6p对TMV的抑制率分别为41%,43%和40%.