Syntheses and properties of new herbicidal 2-arylthio-1 ,2,4-triazolo[1,5-a] pyrimidine derivatives

In search of novel herbicides with high activity, a series of 2-arylthio-1,2,4- triazolo [1, 5-a ] pyrimidines (3) were synthesized by cyclization of 5-amino-3-arylthio-1,2,4-triazoles with 1,3-diketones or by the nucleophilic substitution of substituted thiophenols with 2-methylsulfonyl-1, 2, 4-triazolo [ 1, 5-a]-pyrimidine. The structures of all compounds prepared were confirmed by 1H NMR and MS spectroscopy along with elemental analyses. Preliminary bioassays indicated that some of the compounds 3 had good herbicidal activity against rape. In addition, the regioselectivity in the reaction of 5-amino-3-sub-stituted arylthio-1,2,4-triazoles with benzoylacetone was studied.     

Construction of 6-amino-2,2-dimethyl-3,4,6-trisubstituted-2H-1-benzopyran library by solid phase synthesis

We report the solid-phase library construction of 2000 analogues of 6-amino-2,2-dimethyl-3,4,6-trisubstituted-2H-1-benzopyran. The polymer-bound hydroxyalkoxychromanes 5, produced by nucleophilic reactions with various alcohols on epoxides generated in situ, served as key intermediates for subsequent diversification. Further reactions on these hydroxyalkoxychromanes 5 with various electrophiles, such as alkyl halides and acid halides, produced the desired 6-amino-2,2-dimethyl-3,4,6-trisubstituted-2H-1-benzopyran analogues 9, 10, and 11. The progress of reactions could be monitored as solid-bound intermediates by ATR-FTIR or HR-MAS-NMR spectroscopy. The final compounds, obtained in good yields and high purity upon cleavage from the resins, were characterized by LC/MS, HRMS, (1)H NMR, and (13)C NMR spectroscopy.     

Synthesis and photochemical degradation of N-arylmethyl derivatives of the herbicide 3-amino-1,2,4-triazole

Reaction of an arylmethyl halide with 3-amino-1,2,4-triazole ( 1 ) allows the preparation of the three N-aryl-methyl derivatives of 1 bearing the substituent on the heterocyclic nitrogen atoms. In basic medium (methoxide anion in DMF or methanol, or in benzene by phase transfer catalysis), the isomers 3 and 5 substituted at N-1 and N-2 respectively are obtained, while the isomer 4 is isolated from neutral medium (DMF). The isomers 3 and 4 may be also prepared by cyclization of appropriate formylguanidinium derivatives. 3-Arylmethylamino-1,2,4-triazoles 2 may be obtained through reaction of 3-chloro-1,2,4-triazole ( 6 ) with arylmethylamines. Photolysis of the N-arylmethyl-3-amino-1,2,4-triazoles 2-5 in methanol or water-methanol mixture, induces homolytic and heterolytic cleavage of the arylmethyl-C-N bond giving rise to 3-amino-1,2,4-triazole ( 1 ). Thus, compounds 2-5 with arylmethyl groups able to absorb solar light may be considered as potential photoactivatable herbicides.     

3-(N-取代苯基-2-乙酰胺基)硫基-4-N-取代邻羟苯基亚胺基-5-甲基-1,2,4-三唑类化合物的合成及生物活性研究

以对称二氨基硫脲为原料,与冰醋酸反应生成5-甲基-4-氨基-1,2,4-三唑-3-硫酮(1);在弱酸性条件下,1与取代水杨醛反应生成席夫碱中间体5-甲基-4-(N-取代邻羟苯基)亚胺基-1,2,4-三唑-3-硫酮(2a～2c);最后在碱性条件下分别与N-取代苯基-2-氯乙酰胺发生烷基化反应生成15种未见报道的目标化合物3-(N-取代苯基-2-乙酰胺基)硫基-4-(N-取代邻羟苯基)亚胺基-5-甲基-1,2,4-三唑(3a～3o),其结构经IR,1H NMR,13C NMR确证.初步生物测试表明,质量分数为0.01%时,3a～3o对白色念珠菌的抑菌率均达90%以上,具有很强的抑菌活性;对金黄色葡萄球菌、大肠杆菌的抑菌率达80%以上,具有较强的抑菌活性.     

An aqueous medium synthesis and tautomerism study of 3(5)-amino-1,2,4-triazoles

A catalyst-free highly efficient synthesis of 3(5)-amino-5(3)-(het)aryl-1,2,4-triazoles in aqueous medium was performed using conventional heating and microwave irradiation. The tautomerism in the products was investigated using NMR spectroscopy and X-ray crystallography. The effects of the substitution, temperature, solvents, and concentration on the tautomerism were studied. The triazoles were found to exist in 1H-forms, the 4H-form was not observed either in solid state or in solution. In general, 5-amino-1,2,4-triazoles were electronically preferred in the tautomeric equilibrium, but some exceptions from the established relationship were also identified.     

Die Acylierung von 5-Amino-1 H-1, 2, 4-triazolen. Eine 13C-NMR.-Studie

The Acylation of 5-Amino-1 H-1,2,4-triazoles. A ¹³C-NMR. Study The acylation of 3-substituted-5-amino-1 H-1,2,4-triazoles (1) with methyl chloroformate or dimethylcarbamoyl chloride yielded mainly 1-acyl-5-amino-1,2,4-triazoles ( 2 and 3 ). Acylation of 3-methyl-, 3-methoxy- and 3-methylthio-5-amino-1 H-1,2,4-triazole ( 1b , 1c and 1d ) with methyl chloroformate gave up to 10% of the 1-acyl-3-amino-1,2,4-triazoles. For the unsubstituted 5-amino-1,2,4-triazole (1a) , a (1:1)-mixture of the 3- and 5-isomers 2a and 4 was obtained in dioxane in the presence of triethylamine. No 4-acylated product was detected in contrast to earlier reports. The structures of the reaction products were determined with the aid of proton coupled ¹³C-NMR. spectra using the corresponding N-methyl-1,2,4-triazoles as reference compounds.     

Synthesis and properties of substituted [3-(2-hydroxyphenyl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazol-1-yl]acetonitriles

Alkylation of 3-substituted 5-(2-hydroxyphenyl)-1H-1,2,4-triazoles with chloroacetonitrile gave hitherto unknown N-cyanomethyl derivatives whose structure was determined by X-ray analysis and ¹H and ¹³C NMR spectroscopy. Condensation of substituted [3-(2-hydroxyphenyl)-1H-1,2,4-triazol-1-yl]acetonitriles at the activated methylene group with acetone led to the formation of new 3-methyl-2-triazolylbut-2-enenitrile derivatives.     

Synthesis of 1-Alkyl-5-amino-1,2,4-triazoles Based on Nucleophilic Substitution and Reduction Reactions

A series of 1-alkyl-5-amino-1H-1,2,4-triazoles were synthesized starting from 3,5-dibromo-1H- 1,2,4-triazole by alkylation and subsequent nucleophilic substitution of the 5-bromine atom by azido group, reduction of the latter to amino group, and hydrodebromination.     

Diphenylmethyl and tetrahydropyranyl protecting groups in the synthesis of 3-substituted 5-amino- and 5-hydrazino-1,2,4-triazoles

The use of hydrazine as reagent in nucleophilic substitution and reduction in the 1,2,4-triazole series in combination with introduction of labile protecting groups makes it possible to synthesize 5-hydrazino-3-nitro-1H-1,2,4-triazole and 3-chloro-5-hydrazino-1H-1,2,4-triazol-5-ylhydrazine which were difficultly accessible previously, as well as to extend the series of 3-substituted 5-amino-1H-1,2,4-triazoles. Original Russian Text V.V. Tolstyakov, I.V. Tselinskii, N.A. Dreving, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 12, pp. 2034-2040.     

Synthese de 5-Aryl-3-[(1-dialcoxyphosphonyl)methyl]-1,2,4-triazoles a Partir d'Imidates N-Chloroacyles

A variety of 5-aryl-3-[(1-dialcoxyphosphonyl)methyl]-1,2,4-triazoles 3 has been synthesized efficiently by treatment of trialkylphosphites with 5-aryl-3-chlorométhyl-1,2,4-triazoles 2 . Compound 2 has been prepared by action of N-chloroacylimidates 1 with hydrazines. The structure of triazoles 2 and 3 have been unequivocally confirmed by means of IR, 1 H, 13 C, 31 P NMR spectroscopy and mass spectra.     

含双-三唑并噻二唑环的庚烷类衍生物的合成及抗菌活性

The aroylhydrazides were prepared by esterification and hydrazinolysis of corresponding aromatic carboxylic acids.The reaction of aroylhydrazides with CS2/KOH in absolute ethanol gave potassium aroyldithiocarbazates and then hydrazinolysis of potassium aroyldithiocarbazates with hydrazine hydrate afforded 3-aryl-4-amino-5-mercapto-1,2,4-triazoles(1a～1g).New seven compounds of bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole derivatives(2a～2g) were synthesized in high yields by cyclization of nonanedioic ac...     

双－（3－烷基／芳基）－7H－1，2，4－三唑并[3,4-b]-1,3,4-噻二嗪类化合物的合成及波谱性质

利用1，4－二溴丁二酮（1）分别与3－烷基／芳基－4－氨基－5－巯基－1， 2，4－三唑（2a-2n）反应，合成了14种新的双－（3－烷基／芳基）－7H－1，2， 4－三唑并[3,4-b]－1，3，3-噻二嗪类化合物（3a-3n），并利用EA、IR，~1H NMR和MS确定了其结构。     

Reactions of hydroxyphenyl-substituted 1,2,4-triazoles with electrophylic reagents

Russian Journal of General Chemistry - Reactions of hydroxyphenyl substituted 1,2,4-triazoles with various electrophylic reagents were studied. Despite of the presence of several nucleophilic...     

3-(3,4,5-三甲氧基苯基)-4-氨基-5-取代苄巯基-1,2,4-三唑的合成及其生物活性

3-(3,4,5-三甲氧基苯基)-4-氨基-5-巯基-1,2,4-三唑与取代苄氯反应合成了九个新型3-(3,4,5-三甲氧基苯基)-4-氨基-5-取代苄巯基-1,2,4-三唑(2a～2i),其结构经1H NMR,IR和MS表征.初步生物活性测试结果表明,3-(3,4,5-三甲氧基苯基)-4-氨基-5-对氯苄巯基-1,2,4-三唑(2b)对半夏立枯病菌具有抑制活性.     

A Novel and Convenient Preparation of 1-(γ-Aminoalkyl)-Substituted 1,2,4-Triazoles

1-(α-Aminomethyl)-1,2,4-triazoles readily add to enol ethers or enamides to give novel classes of compounds, 1-(γ-amino-α-alkoxy)propyl- (8) and 1-(γ-amino-α-amido)propyl- (10) substituted 1,2,4-triazoles, in excellent yields.     

Reactions of 3-amino-1,2,4-triazoles with cinnamic aldehydes

The reaction of 3-amino- and 3-amino-5-methylthio-1,2,4-triazoles with cinnamaldehyde takes two directions to form mixtures of 5-[N-(3-phenylpropenylideneamino)]-1H-1,2,4-triazoles and 5-phenyl-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidin-7-ols.     

3-(3-吡啶基)-4-氨基-5-芳胺基-1,2,4-三唑的合成与表征

以烟酸与芳胺为基本原料，经多步反应，制得1－烟酰基－4－芳基氨基硫脲；后者在水合肼存在下关环，合成了一系列新化合物3－（3－吡啶基）－4－氨基－5－芳胺基－1，2，4－三唑。化合物结构经元素分析、IR，^1H NMR,^13C NMR确证。     

6-取代-3-（3，4，5-三甲氧基苯基）-1，2，4-三唑[3,4-b][1,3,4]噻二唑的合成与生物活性

以3,4,5-三甲氧基苯甲酸为原料,通过4步反应得到4-氨基-5-(3,4,5-三甲氧基苯基)-3-巯基-1,2,4-三唑,再与取代芳酸反应,得到11个6-取代-3-(3,4,5-三甲氧基苯基)-1,2,4-三唑[3,4-b][1,3,4]噻二唑衍生物5a～5k。其结构经IR,1H NMR,MS和元素分析确证。初步生物活性测试结果表明部分化合物有一定的杀菌活性。     

Synthesis of heterocycles. Part VI. Synthesis and antimicrobial activity of some 4-amino-5-aryl-1,2,4-triazole-3-thiones and their derivatives

4-Amino-5-aryi-1,2,4-triazole-3-thiones I react with acid chlorides to yield 4-acylamino-5-aryl-1,2,4-triazole-3-thiones II. Compounds I also react with methylene iodide, chloroacetonitrile and methyl bromoacetate to give bis-(4-amino-5-aryl-1,2,4-triazol-3-ylthio)methanes III, 4-amino-5-aryl-3-cyanomethylthio-1,2,4-triazoles IV and 4-amino-5-aryl-3-carbomethoxymethylthio-1,2,4-triazoles V, respectively. Compounds V react with hydrazine hydrate to give the corresponding acid hydrazides VI which in turn condenses with acid chlorides and aldehydes to afford respectively 1-[(4-amino-5-aryl-1,2,4-triazol-3-ylthio)acetyl]-2-aroylhydrazines VII and aryl methylene (4-amino-5-aryl-1,2,4-triazol-3-ylthio)acethydrazones VIII. The antimicrobial activities of the above compounds were screened against different strains of bacteria and fungi.     

Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride)

Contrary to a previous report, the sulfurisation of phosphorus(III) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett rho-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are approximately -1.0. The entropies of activation are very negative (-114+/-15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of DeltaS(not equal) and rho values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations.