Syntheses of 3-[5-Methyl-1-(4-Methylphenyl)-1,2,3-Triazol-4-yl]-6-Substituted-s-Triazolo[3,4-b]-1,3,4-Thiadiazoles

1,2,3-Triazole derivatives have been reported as inhibiting tumor proliferation, invasion, and metastasis^[1]. The fused l,3,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives show various biological effects such as antifungal^[2], antibacterial, hypotensive and CNS depressant activities^[3]. We have reported several 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazoles in the previous paper^[4]. The novel 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[2,4-b]-1,3,4-thiadiazoles 6a-j have been synthesized by the condensation of 4-amino-5-mercapto-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazole 5 with various aromatic carboxylic acids in the presence of phosphorus oxychloride. The mercaptotriazole 5 was prepared from 4,the latter being prepared from 1 throng 2 and 3. The title compounds 6 were depicted in scheme 1. The structures of these compounds were established by elemental analysis, NMR, MS and IR techniques.     

Synthesis of 3-(2-Phenylquinolin-4-yl)/3-(l-p-Chlorophenyl-5-methyl-1, 2,3-triazol-4-yl)-s-triazolo[3,4-b]-1, 3,4-thiadiazine Derivatives

s-Triazolo[3, 4-b]-1,3,4-thiadiazine derivatives constitute an important class of organic compounds with diverse biological activities. 2-Phenylquinoline and 1,2, 3-triazole derivatives are very attractive heterocyclic systems due to their wide use in medicine, agriculture and industry^[1]. Incorporation of 2-phenylquinoline and 1,2,3-triazole moiety into the 3-position of s-triazolo[3,4-b]-l, 3,4-thiadiazine ring system may enhance their biological activity. In light of the above findings, we synthesized some new s-triazolo[3, 4-b]-1, 3, 4-thiadiazine derivatives 2a-b~6a-b by the condensation of 4-amino-5-mercapto-3-(2-phenylquinolin-4-yl)/3-(1-p-chlorophenyl-5-methyl-1, 2,3-triazol-4-yl)-1, 2, 4-triazoles 1a-b with chloroacetalde-hyde, ω-bromo-ω-(1H-1, 2, 4-triazol-1-yl)acetophenone, chloranil, 2-bromocyclohexanone, 2, 4'-dibromoacetophenone, respectively.     

Synthesis of 6-(6-/8-Substituted-4-Chloro-Quinoline-3-yl)-3-Aryl-s-Triazolo[3,4-b] -1,3,4-Thiadiazoles

A survey of literature^[1] revealed that s-triazolo[3,4-b]-1,3,4-thiadiazole has received much attention during recent years on account of its prominent utilization as antifugal, anti-inflammatory, analgsic and anthelmintic agents probably resulting from its planner and compact structure. In the course of the study of this ring system, we previously described a series of 3,6-disubstituted-s-triazolo[3,4-b]-1,3,4-thiadiazoles which exhibited antibacterial, herbicidal and plant growth regulative activities. It is well known that quinoline derivatives are associatied with broad spectrum biological activities^[2].     

Studies on Reactions of 2-Amino-5-Heterocyclyl-1,3,4- -Thia/Oxadiazole with Acylisothiocyanates

It is well known that the addition of acyl isothiocyanate with amine formed 1,3-disubstituted thiourea which possess broad spectrum biological activities, Up till now, the addition of 5-heterocyclyl-2-amino-1,3,4-thia/oxadiazole with acylisothicyanate has not been reported. We wish to describe this reaction in this paper. When the new 2-amino-5-(l-p-chlorophenyl-5-methyl-1,2,3-triazol-4-yl)-1,3,4-thiadiazole (Ⅰ) was reacted with acylisothio-cyanates (Ⅱ), not all the compounds were expected acylthiourea (Ⅲ)^[1,2], some of them were acid amide (Ⅳ). The formation of the products was determined by the substituents of the acylisothiocyanate. In order to investigate the reaction, we synthesized 2-amino-5-aryl-1,3,4-thio/oxadiazole (Ⅴa,b), and then reacted with 1-p-chlorophenyl-5-methyl-1,2,3-triazol-4-formyl-isothiocyanate (Ⅵ). As it was anticipated, the products only were N-(5-aryl-1,3,4-thia/oxadiazol-2-yl)-N'-(1-p-chlorophenyl-5-methyl-1,2,3-triazol-4-formyl) thiourea (Ⅶa,b) (Scheme).     

Synthesis of 6-(1-Aryl-5-methyl-1,2,3-triazol-4-yl)-3-(4-Pyridyl)-s-Triazolo[3,4-b]-l,3,4-Thiadiazoles

A survey of literature¹ revealed that s-triazolo[3,4-b]-1,3,4-thiadiazole, an interesting fused system of s-triazole and 1,3,4-thiadiazole rings, has received much attention during recent years on account of its prominent utilizations as antifungal, antiinflammatory, antiviral, analgesic and anthelmintic agents probably resulting from its planner and compact structure. Our earlier work on the synthesis of this class of heterocycles showed antibacterial, herbicidal and plant growth regulative properties^2-3 for the compounds. 1,2,3-Triazole derivatives have found their wide use in medicine, agriculture and industry^4-5. Incorporation of 1,2,3-triazole moiety into the 6-position of this ring system may lead to achieving compounds of better biological activities. In view of the above findings coupled with scanty reports on these condensed compounds carrying 6-heterocyclic groups, we wish to report here the condensation of 4-amino-5-mercapto-3-(4-pyridyl)-l,2,4-triazole(2) with 1-aryl-4-carboxy-5-methyl-1,2,3-triazoles(1_a-j) as a part of our continuing interest in this area.     

Synthesis and selected transformations of 1-(5-methyl-1-aryl-1H-1,2,3-triazol-4-yl)ethanones and 1-[4-(4-R-5-methyl-1H-1,2,3-triazol-1-yl)phenyl]ethanones

By cycloaddition of arylazides to acetylacetone are obtained derivatives of 1,2,3-triazole. In the reaction of 1-[5-methyl-1-(R-phenyl)-1H-1,2,3-triazol-4-yl] ethanones (IIa–IIe) and 1-[4-(4-R-5-methyl-1H-1,2,3-triazol-1-yl)phenyl] ethanones (VIIa-VIIe) with isatin are obtained 2-[1-(R-phenyl)-5-methyl-1H-1,2,3-triazol-4-yl]-4-quinolinecarboxylic acids (IIIa–IIIe) and 2-[4-(4-R-5-methyl-1H-1,2,3-triazol-1-yl)phenyl] -4-quinolinecarboxylic acids (IXa, IXb), respectively. We found that 1-[5-methyl-1-(R-phenyl)-1H-1,2,3-triazol-4-yl] ethanones (IIa–IIe) readily transform into [5-methyl-1-(R-phenyl)-1H-1,2,3-triazol-4-yl] acetic acids (IVa–IVc) by the method of Wilgerodt-Kindler. The (5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)acetic acid reacts with 5-phenyl-4-amino-4H-1,2,4-triazol-3-thiol affording 6-[(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl) methyl]-3-phenyl[1,2,4] triazolo[3,4-b] [1,3,4] thiadiazole (VI). Original Russian Text ? N.T. Pokhodylo, R.D. Savka, V.S. Matiichuk, N.D. Obushak, 2009, published in Zhurnal Obshchei Khimii, 2009, vol. 79, no. 2, pp. 320–325.     

The Synthesis and Fungicidal Activities of 2,6-Bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]pyridines

In search of better bioactive compounds, a series of novel 2,6-bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]pyridines 2 were synthesized in high yields by the cyclization of 3-aryl-4-amino-5-mercapto-1, 2, 4-triazoles 1 with 2,6-pyridine dicarboxylic acid. 2 exhibited good fungicidal activities against Cerospora beticola sacc.     

Synthesis and antibacterial activities of novel imidazo[2,1-b]-1,3,4-thiadiazoles

2-Amino-5-(2-aryl-2H-1,2,3-triazol-4-yl)-1,3,4-thiadiazoles 2-4 have been synthesized by the reaction of 2-aryl-2H-1,2,3-triazole-4-carboxylic acids 1 with thiosemicarbazide. Their reaction with phenacyl (p-substituted phenacyl) bromides led to formation of the respective 6-aryl-2-(2-aryl-2H-1,2,3-triazol-4-yl)imidazo[2,1-b]-1,3,4-thiadiazoles 5. Reactivity of the latter fused ring towards reaction with different electrophilic reagents afforded the corresponding 5-substituted derivatives 6-8. The structure of the above compounds was confirmed from their spectral characteristics. Some of these compounds were found to possess slight to moderate activity against the microorganisms Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and Escherichia coli.     

Synthesis and Crystal Structure of 3,6-Bis（4-methyl-1,2,3-thiadiazol-5-yl）-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole

The compound 3,6-bis(4-methyl-1,2,3-thiadiazol-5-yl)-1,2,4-triazolo[3,4-b][1,3,4] thiadiazole(C9H6N8S3,Mr = 322.40) has been synthesized by the reaction of 4-amino-3-(4-methyl-1,2,3-thiadiazolyl)-5-mercapto-1,2,4-triazole with 4-methyl-1,2,3-thiadiazol-5-carboxylic acid and phosphorus oxychloride,and its structure was characterized by IR,1H NMR,EI-MS,elemental analysis and single-crystal X-ray diffraction.The crystal of the title compound belongs to monoclinic,space group C2/c with a = 2.0053(4),b = 1.3081(3),c = 1.0556(2) nm,β = 112.69(3)°,Z = 4,V = 2.5548(9) nm3,Dc = 1.676 g/cm3,μ = 0.582 mm-1,F(000) = 1312,R = 0.0546 and wR = 0.1523.X-ray analysis indicates that all rings are essentially planar in this molecule,and an intermolecular hydrogen bond C(9)-H(9)…N(2) and weak intramolecular interactions between S(1)…N(7),S(3)…N(1) and S(2)…N(4) are observed.     

Studies on Condensed Heterocyclic Compounds XVII. Synthesis of 6-(1-Aryl-5-methyl-1,2,3-triazol-4-yl)-3-phenyl-s-triazolo[3,4-b]-1,3,4-thiadiazoles

Treatment of 4-amino-5-mercapto-3-phenyl-1,2,4-triazole 2 with 1-aryl-4-carboxy-5-methyl-1,2,3-triazoles 1a-1j in a one-step reaction yielded several 6-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-3-phenyl-s-triazolo[3,4-b]-1,3,4-thiadiazoles 3a-3j . The structures of all the products were established on the basis of elemental analyses and spectral data. The fragmentation of the mass spectra of 3a-3j under electron impact was discussed.     

Syntheses of Chiral Fused Heterocyclic Compounds Containing l,2,4-Triazole Ring

The chemistry of life is based considerably on chirality. Consequently, stereospecificity has to be regarded as an especially important characteristic of biological systems. The influence of stereospecificity of the biological activities of enzyme inhibitors or compounds binding to receptor is a well known fact in the field of drug action^[1]. s-Triazoles and l,3,4-thiadiazoles are reported to exhibit broad spectrum of biological and pesticidal activities^[2-3].In recent years, bridge head nitrogen heterocycles have received much attention as anthelmintic agents, however, it is not observed that the syntheses of chiral fused heterocyclic compounds containing s-triazoles and l,3,4-thiadiazoles. In order to study the relationship between stereochemistry and the performance of fungicides, we have synthesized a series of (s)-1,2-di(3-aryl-s-triazolo[3,4-b][1,3,4] thiadiazolo-6-yl) ethylamine and (s)-1-(3-aryl-s-triazolo[3,4-b][l,3,4] thiadiazolo-6-yl) ethylamine by the condensation of 3-aryl-4-amino-5-mercapto-1,2,4-triazoles with L-aspartic acid and L-alanine in the presence of phosphorusoxychloride.     

Synthesis of 3- [ 1- (4-Ethoxyphenyl)-5-methyl-1,2,3-triazol-4-yl ]-6- substituted- s-triazolo [ 3,4- b ] -1,3,4-thiadiazoles

Several 3- [ 1- (4-ethoxyphenyl)-5-methyl- 1,2, 3-triazol-4-yl ]-6-substituted-s-triazolo [ 3,4- b ]- 1,3,4-thiadia zoles have been synthesized and the structures of these compounds were established by MS, IR and 1H NMR spectral data.     

含三唑基的新型咪唑[2,1-b]-1,3,4-噻二唑的合成及表征

以2-(2-苯基-1,2,3-三唑-4-基)-5-氨基-1,3,4-噻二唑(1)为原料分别与ω-溴代芳基乙酮、ω-溴代-ω-(1H-1,2,4-三唑-1-基)芳基乙酮反应, 合成了一系列新型咪唑[2,1-b]-1,3,4-噻二唑类化合物2a～2e和3a～3e. 其结构经IR, ¹H NMR和MS及元素分析确证.     

Synthesis of [5-(1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl)-1,3,4-oxadiazol-2-yl]pyridines

2-, 3-, and 4-[5-(1-Aryl-5-R-1H-1,2,3-triazol-4-yl)-1,3,4-oxadiazol-2-yl]pyridines were synthesized from the corresponding 1-aryl-5-R-1H-1,2,3-triazole-4-carbonyl chlorides and 2-, 3-, and 4-(1H-tetrazol-5-yl)-pyridines.     

Synthesis of 1,3-Bis[(3-aryl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes

1,3-bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes 2 were synthesized in high yields by the reaction of 3-aryl 4-amino-5-mercapto-1,2,4-triazole 1 with m-phthalic acid.     

高选择性检测Hg2+的喹啉酮衍生物荧光探针的合成及应用

设计合成了一种以喹啉酮为荧光团,具有新型结构的荧光探针（E）-N-（4-甲基-2-氧代-1,2-二氢喹啉-7-基）-3-（3-苯基-[1,2,4]三唑[3,4-b][1,3,4]噻二唑-6-基）丙烯酰胺（MNT）.研究结果表明,MNT可通过不饱和酰胺键异构化后与Hg²⁺配位,从而产生显著的荧光猝灭.1,2,4-三唑[3,4-b]-1,3,4-噻二唑缺电子的特征有助于提高猝灭效果的同时,能提供与Hg²⁺配位的杂原子.MNT探针对Hg²⁺具有高选择性、较高的量子产率和较强的抗干扰性,检测限为6.35×10^-8 mol/L,响应时间25 s.进一步研究发现,MNT在pH=4~13范围内均能特异性检测Hg²⁺.基于核磁滴定实验结果推测了该探针荧光检测Hg²⁺的机理,并由Job’s曲线确定了MNT与Hg²⁺之间的配位比为2：1.MNT在实际水样中的应用结果表明其可作为检测Hg²⁺的荧光探针.     

Synthesis of 6-aryl-3-cinchophenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles

In recent years, fused heterocycles have been found to possess many unique properties in synthesis and pharmacology. Especially, 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives have been attracting much attention of chemists and pharmacologists because of their broad-spectrum biological activities such as antibacterial¹, hypotensive and CNS depressant² activities. We have prepared some 3,6-substituted 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles and found that these compounds exhibited antimacrobial, insecticidal and promote plant growth.^3-5 Cinchophen had been used widely as medicine in clinic,but has been obsolete in recent years due to its by-effect. In order to seek for other uses of cinchophen, as a continuation of our preceeding studies, we used cinchophen as the starting material to synthesize ten new 6-aryl-3-cinchophenyl-l,2,4-triazolo[3,4-b]-l,3,4-thiadiazoles 5a-j. Compound 1 was prepared by the reaction of cinchophen and ethanol in the presence of sulfuric acid. 1 then reacted with hydrazine hydrate in absolute ethanol to give 2 which yielded 3 on treatment with CS₂ and KOH. On refluxing of 3 with excess hydrazine hydrate, 4 was obtained. 4 reacted with various substituted benzoic acids in the presence of POCl₃ to afifort 5a-j.     

Studies on Condensed Heterocyclic Compounds XVI. Synthesis of 3-Alkyl-6-(2,4-Dichlorophenoxymethyl)-s-Triazolo[3,4-b]-1,3,4-Thiadiazoles and 6,6′-Bis(3-Aryl-s-Triazolo[3,4-b]-1,3,4-Thiadiazoles)

Several 3-alkyl-6-(2,4-dichlorophenoxymethyl)-s-triazolo[3,4-b]-1,3,4-thiadiazoles 3a-3e and 6,6′-bis(3-aryl-s-triazolo[3,4-b]-1,3,4-thiadiazoles) 3f-3j were synthesized. The structures of all the compounds synthesized were elucidated by elemental analyses and spectral data. The representative compounds 3a and 3b exhibited moderate biological activities.     

新型1,2,4-三唑[3,4-b]-1,3,4-噻二嗪的合成及表征

以3-(2-苯基-1,2,3-三唑-4-基)-4-氨基-5-巯基-1,2,4-三唑(1)为原料分别与ω-溴代芳基乙酮、ω-溴代-ω-(1H-1,2,4-三 唑-1-基)芳基乙酮反应, 合成了一系列新的1,2,4-三唑[3,4-b]-1,3,4-噻二嗪类化合物2a～2e和3a～3e. 其结构经IR, ¹H NMR和MS及元素分析确证.     

1,2,3-Selenadiazolyl-1,3,4-oxadiazole, 1,2,3-Thiadiazolyl-1,3,4-oxadiazole and 5-(1,2,3-Thiadiazolyl)-s-triazolo[3,4-b]-1,3,4-thiadiazoles

A series of 5-substituted-2-(4-alkyl or phenyl-1,2,3-thia(or selena)diazol-5-yl)-1,3,4-oxadiazoles were prepared. 5-Substituted-2-(4-phenyl-1,2,3-selenadiazol-5-yl)-1,3,4-oxadiazoles upon pyrolysis afforded the corresponding alkynes. Also, a series of 5-substituted-4-amino-3-(1,2,3-thiadiazol-5-yl)-s-triazoles and 5-(1,2,3-thiadiazolyl)-s-triazolo[3,4-b]-1,3,4-thiadiazoles were prepared.