Reactions of some 5-substituted imidazo[2,1-b]-1,3,4-thiadiazoles

The conversion of the 5-bromoimidazo[2, 1-b]-1, 3, 4-thiadiazole Ib to the 5-cyano derivative Ic is firstly described. The 5-nitroimidazo[2, 1-b]-1, 3, 4-thiadiazole Id is smoothly reduced by aluminium amalgam to the 5-imino-5, 6-dihydroimidazo[2, 1-b]-1, 3, 4-thiadiazole II. However, reaction of Id with sodium dithionite unexpectedly gives 1, 3, 4-thiadiazoles III and V depending upon conditions.     

1,2,4-三唑并[3,4-b]-1,3,4-噻二唑的合成

近年来稠杂环化合物的合成及其生物活性的研究日益成为杂环化学研究的热门课题。3,6-二取代-1,2,4-三唑并噻二唑衍生物是具有广谱生物活性的稠杂环化合物,如抗菌、消炎、杀微生物、调节植物生长、除草等,因而引起各国化学家的广泛兴趣。此类化合物的生物活性,     

含有异(口恶)唑的S-三唑[3,4-b]-1,3,4-噻二嗪、咪唑[2,1-b]-1,3,4-噻二唑和咪唑[2,1-b]-1,3,4-(口恶)二唑衍生物的合成

异噁唑衍生物作为一类重要的生物活性物质[1,2],其合成一直受到人们的关注,其中德国HMR公司开发研制的新型抗内风湿性关节炎药来氟米特(Leftunomide)已于1998年在美国率先上市,该药还具有很好的免疫调节作用[3].7H-均三唑[3,4-b]-1,3,4-噻二嗪、咪唑并[2,1-b]噻唑和咪唑并[2,1-b]-1,3,4-噻二唑衍生物均表现出广谱的生物活性[4～6].     

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...     

Research on heterocyclic compounds. XXI. Synthesis of imidazo[2,1-b]benzothiazole and imidazo[2,1-b]thiazole derivatives

The reaction of some 2-aminobenzothiazoles and 2-aminothiazoles with ethyl 3-bromo-4-oxopentanoate was investigated with the aim to obtain the corresponding imidazo[2,1-b]benzothiazole and imidazo[2,1-b]-thiazole derivatives, respectively. In some cases, two unexpected side products were obtained together with the required compound and their structures were elucidated: e.g., 2-aminobenzothiazole reacted with ethyl 3-bromo-4-oxopentanoate to give ethyl 2-methylimidazo[2,1-b]benzothiazole-3-acetate together with ethyl imi-dazo[2,1-b]benzothiazole-2-propionate and ethyl 3-(benzothiazol-2-yl)amino-4-oxopentanoate.     

1,3,4-均三唑并[2,1-b]-1,3,4-噻二唑衍生物的合成及生物活性

以5-对甲苯基-1-氨基-2-巯基-1,3,4-均三唑和取代苯氧乙酰异硫氰酸酯为原料, 合成了10个未见文献报道的5-对甲苯基-2-取代苯氧乙酰氨基均三唑并[2,1-b]-1,3,4-噻二唑类化合物, 通过元素分析, 1H NMR, IR和MS确定化合物的结构, 初步生物活性测试表明目标化合物具有较好的除草活性.     

Imidazo[2,1-b]benzothiazoles. II. Synthesis and antiinflammatory activity of some imidazo[2,1-b]benzothiazoles

3-[2-[p-(Un)substituted phenyl]imidazo [2,1-b]benzothiazol-3- yl]propionic acid derivatives (2a--e) were prepared via the interaction of the corresponding 2-[p-(un)substituted phenyl]imidazo[2,1-b]benzothiazoles (1a--e) with acrylic acid in the presence of acetic anhydride and acetic acid. Esterification of 2a--e produced methyl esters (3a--e). Upon the interaction of 3a with m-chloroperbenzoic acid, the S-dioxide (4a) was obtained. Compound 5a was prepared from 4a by alkaline hydrolysis. Vilsmeier formylation for 1a--e produced novel [2-[p-(un)substituted phenyl]imidazo[2,1-b]benzothiazol-3- yl]formaldehyde derivatives (6a--e). Derivatives 6a--e reacted with ethyl bromoacetate to give ethyl 3-hydroxy-3-[2-[p-(un)substituted phenyl]imidazo[2,1-b]benzothiazol- 3-yl]propionate esters (7a--e). Compound dl-7a was resolved with l-(+)-tartaric acid. Compounds 2a--e showed weak or no activity in the carrageein-induced paw edema assay. Compound 4a significantly inhibited the leakage of pontamine-sky blue dye into the peritoneal cavity of mice, in the capillary permeability inhibition assay. Compound 5a inhibited the writhing by 62% in the acetic acid-induced writhing assay.     

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.     

3-烷基-6-芳氧亚甲基均三唑并[3,4,-b]-1,3,4-噻二唑的合成

在POCl~3存在下,3-烷基-4-氨基-5巯基-1,2,4-三唑分别同植物生长激素2,4-二氯苯氧乙酸和β-萘氧乙酸缩合得到了12个新的化合物. 化合物的结构经元素分析,IR,^1H NMR , 以及MS等方法确证.初步生物测定实验表明,其中某些产物具有调节植物生长和抑制植物病原菌的作用.     

3—吡唑基—6—取代均三唑并[3,4—6]—1,3,4—噻二唑的合成及生物活性

以１－甲基－３－乙基（４－氯）－５－哟唑甲作原料，经两步得到４－氨基－３－（１－甲基－３－乙基（４－氯）－５－吡唑基）－１，２，４－三唑－５－硫酮（３），３再与取代酸反应，得到一系列３（１－甲基－３－，乙基（－４－氯）－５－吡唑基）－６－取代均三并「３，４－ｂ」－１，３，４－噻二唑（４，５，６），元素分析、ＨＮＭＲ、ＩＲ和ＭＳ确定了它们的结构，初步生侧结果表明，３具有植物生长调节活性，４ｂ、４ｄ、     

Synthesis and antiviral activity of novel imidazo[2,1-b]thiazoles coupled with morpholine and thiomorpholines

Herein described the synthesis and antiviral evaluation of a novel series of morpholine and thio-morpholine coupled imidazo[2,1-b]thiazoles. The three-step reaction sequence involving the condensation of 1,3-dichloroacetone with thiourea followed by coupling with morpholine and thiomorpholine and finally cyclization with substituted α-bromoacetophenones yielded the desired imidazothiazoles 7(a–l) . Screening of all the new compounds for their in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells, resulted in two potent analogs, 7d (IC₅₀: 1.1 μM, C₅₀: >300 μM, SI = 273) and 7e (IC₅₀: 2.0 μM, C₅₀: >300 μM, SI = 150), with a favorable toxicity profile and are the best anti-influenza hit analogs for further structural optimization.     

Synthesis and Structure of 2-Isobutyl-6-(2'''',4''''-dichlorophenyl)imidazo[2,1-b]-1,3,4-thiadiazole

1INTRODUCTIONThethiadiazoleandimidazolecompoundsareextensivelystudiedduetotheirspectrumbioacti-vities[1～4].Amongthem,theimidazo[2,1-b]-1,3,4-thiadiazolederivativesarepharmaceuticallyimpor-tantbecauseoftheirimmunostimulant[5],antifugal[6],antimicrobial[7]…     

Synthesis of pyrido[2,1-b]- and thiazolo[2,3-b]purines

Some pyrido[2,1-b]- and thiazolo[2,3-b]purines, tricyclic compounds structurally related to [1,2,4]triazolo[1,5-c]quinazolines 1 have been synthesized with a view to study their possible adenosine and benzodiazepine receptors affinity.     

含有1H-1,2,4-三唑咪唑[2,1-b]-1,3,4-噻二唑、S-三唑[3,4-b]-1,3,4-噻二唑衍生物的合成及生物活性

合成了18个含有1H-1,2,4-三唑的咪唑[2,1-b]-1,3,4-噻二唑以及S-三唑[3,4-b]-1,3,4-噻二唑的稠杂环衍生物,经元素分析及谱学表征,探讨2,5,6-三取代咪唑[2,1-b]-1,3,4-噻二唑的可能生成机制.对大肠杆菌、绿脓杆菌、枯草杆菌等初步抑菌试验证明,多数化合物表现了较好的抑菌活性.     

新型3,6-二取代-1,2,4-三唑[3,4-b]-1,3,4-噻二唑衍生物的合成、表征及生物活性

以4-氨基-5-[2-(4-氯苯氧甲基苯并咪唑)-1-亚甲基]-3-巯基-1,2,4-三唑(6)和不同的芳香酸为原料, 在三氯氧磷的作用下环化合成了17个新型3-[2-(4-氯苯氧甲基苯并咪唑)-1-亚甲基]-6-芳基-1,2,4-三唑[3,4-b]-1,3,4-噻二唑衍生物7. 利用IR, ¹H NMR和元素分析对新化合物6和7的结构进行了表征. 初步的生物活性实验结果表明, 化合物7a和7b在20 μg/mL时对大肠杆菌甲硫氨酰氨肽酶(EcMetAP1)具有较高的抑制活性, 抑制率分别为87.26%和82.62%, 化合物7f, 7h和7l具有中等的抑制活性. 化合物7a～7q在20 μg/mL时对细胞分裂周期(cdc25B)磷酸酯酶均具有抑制活性, 其中化合物7b, 7g和7i在5 μg/mL时仍具有很高的抑制活性, 抑制率分别为98.76%, 83.87%和90.57%. 杀菌、杀虫、除草和植物生长调节活性筛选测定实验结果表明, 所测试的目标化合物7d～7e, 7h～7m和7o～7q均无活性.     

Synthesis,characterization and antimicrobial activity evaluation of new 2,4-Thiazolidinediones bearing imidazo[2,1-b][1,3,4]thiadiazole moiety

The synthesis and antimicrobial activity of 2,4-thiazolidinedione derivatives 5a–g and 6a–g are described. The structures of the newly synthesized compounds were confirmed by IR, NMR, mass and elemental analyses. All compounds were evaluated for their preliminary in vitro antibacterial and antifungal activity. The results revealed that most of the compounds showed high or moderate biological activity against tested microorganisms.