Chemoselective one-pot synthesis of 2-phenylamino-5-alkylthio-1,3,4-thiadiazole derivatives from phenylthiosemicarbazide and CS2

A novel and fairly efficient chemoselective one-pot method has been developed for the synthesis of both 2-phenylamino-5-alkylthio-1,3,4-thiadiazole and bis-(2-phenylamino-5-alkylthio-)1,3,4-thiadiazole derivatives from phenylthiosemicarbazide and CS₂.     

Synthesis of novel thiadiazoles and bis-thiadiazoles from carbonothioic dihydrazide

Efficient syntheses of 1,3,4-thiadiazoles and bis-thiadiazoles by the reaction of hydrazonoyl halides with carbonothioic dihydrazide are reported. In addition, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole is obtained via oxidative cyclization of bis-(substituted methylene)carbonothioic dihydrazone.     

新的双枝[1,3,4]-噁二唑衍生物的设计与微波合成

在微波辐射条件下,以三氯氧磷作环合剂,以双酰肼为中间体,快速有效地合成了一系列新的1,3-二[(5-芳基-1,3,4-噁二唑-2-基)甲氧基]苯类化合物.十二个目标化合物(5a-5l)和五个中间体(4c,4d,4e,4j,4k)均为未见文献报道的新化合物,其结构经核磁、红外、质谱和元素分析所确证.该方法的显著优点是简单...     

Synthesis of 1,3,4-thiadiazines,bis-1,3,4-thiadiazoles, [1,2,4]triazino[3,4-b][1,3,4]thiadiazine,thiazolines from carbonothioic dihydrazide

A novel and efficient synthesis of 1,3,4-thiadiazines, bis-1,3,4-thiadiazoles, [1,2,4]triazino[3,4-b][1,3,4]thiadiazine, and thiazolines is reported from the reaction of α-haloketo hydrazonoyl halides with carbonothioic dihydrazide or its analogues. The structures were elucidated on the basis of their elemental analysis, spectral data and an alternative synthetic route.     

Synthesis and study of polyurethanes and polyurea urethanes based on the diamino derivatives of bis-1,3,4-oxadiazole

Polyurethanes were synthesized by condensation of diamino derivates of bis-1,3,4-oxadiazole with chloroformates, and polyurea urethanes were synthesized from diamino derivaties of bis-1,3,4-oxadiazole, diisocyanates, and ethylene glycol in a solution of dimethylformamide. Certain properties of these compounds were studied.     

Synthesis of arylethylene derivatives of 2, 5-diphenyl-1, 3, 4-oxadiazole

The synthesis of arylethylene derivatives of 2,5-diphenyl-1,3,4-oxadiazole by the Wittig reaction from 2-(p-bromomethylphenyl)-5-phenyl-1,3,4-oxadiazole and aromatic aldehydes is described. The compounds obtained fluoresce strongly on irradiation with UV light.     

含双1,3,4-噁二唑类荧光化合物的合成及荧光性能

在丙基磷酸酐催化条件下,由对甲基苯甲酸和取代苯甲酰肼通过环合反应得到含甲基的1,3,4-噁二唑单环,经高锰酸钾氧化反应得到单环1,3,4-噁二唑芳香酸;然后再次利用丙基磷酸酐的催化效应,实现芳香酸与邻羟基苯甲酰肼的环合反应,制备得到含双1,3,4-噁二唑结构的荧光化合物.利用红外光谱仪和核磁共振谱仪表征了合成产物的结构,并测定了产物的元素组成和荧光性能.结果表明,各合成产物的总收率为44%～49%;目标化合物具有较大的Stokes位移.     

Synthesis and Antimicrobial Properties of New Thiosemicarbazide, 1,2,4-Triazole,and 1,3,4-Thiadiazole Derivatives of Sulfanylacetic Acid

Abstract

1,2,4-triazole and 1,3,4-thiadiazole derivatives are still considered a viable lead structure for the synthesis of more efficient antimicrobial agents having a broad spectrum of activity. This study presents the synthesis and antimicrobial evaluation of a new series of substituted 1,2,4-triazole and 1,3,4-thiadiazole derivatives. Reaction of 4-phenyl-5-(pyridin-3-yl)-4H-1,2,4-triazole-3-thione with ethyl bromoacetate yields the corresponding ethyl acetate (1). In the subsequent reaction with 100% hydrazine hydrate, the hydrazide (2) was obtained, which was converted with isothiocyanates to new acyl derivatives of thiosemicarbazide (3a–l). The cyclization of these compounds in alkaline media resulted in the formation of new derivatives of 1,2,4-triazole (4a–i), whereas in acidic media new derivatives of 1,3,4-thiadiazole (5a,b,g) were obtained. All synthesized compounds were screened for their in vitro antimicrobial activities.     

Synthesis and Reactivity of Enaminones: Synthesis of Some 1,3,4‐Thiadiazole Linked to Pyrazole,Pyridine, Benzimidazolopyrimidine,Pyrazolopyrimidine, Pyrazolotriazine and Triazolotriazine Derivatives

1,3,4‐Thiadiazole‐enaminone ( 6 ) was synthesized via reaction of the benzamide ( 5 ) with DMF‐DMA. The simple thiadiazole‐enaminone ( 6 ) was used as a synthetic precursor for the synthesis of a wide variety of new heterocyclic compounds, including the 5‐substituted‐1,3,4‐thiadiazole derivatives ( 7 ), ( 8 ), ( 16 ), ( 17 ) and ( 18 ), which were obtained via reactions of ( 6 ) with nitrogen nucleophiles. Also, reactions of enaminone ( 6 ) with carbon nucleophiles afforded the respective 1,3,4‐thiadiazoles ( 10a , 10b ). Diazotization of the benzamide ( 20 ) with the heteroaromatic amine salts gave the hydrazone derivatives ( 21 ) and ( 22 ). Cyclization of the latter hydrazones yielded the corresponding pyrazolotriazine and 1,2,4‐triazolotriazine derivatives ( 23 ) and ( 24 ), respectively. All newly synthesized compounds were elucidated by considering the data of both elemental and spectral analysis.     

Thermally stable polymers containing 1,3,4-oxadiazole units obtained from Huisgen reaction

Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble even in polar aprotic solvents such as DMSO and DMF.Relatively high inherent viscosity values（0.61-1.33 dL/g,in 0.125%H₂SO₄ at 25℃） were observed for these compounds.Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers have improved thermal stabilities.The glass transition temperature has not been observed in the fully aromatic polymers,but the polymers obtained from 5-[6-（1H-tetrazol -5-yl）hexyl]-lH-tetrazole（Ⅳ） showed very clear T_g.A model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compound was characterized by conventional spectroscopy methods.     

Synthesis,Reactions, and Anticancer Activity of Some 1,3,4-Thiadiazole/Thiadiazine Derivatives of Carbazole

A novel method for the synthesis of 1,3,4-thiadiazole and 1,3,4-thiadiazine derivatives bearing a carbazole moiety is described. Carbazole was transformed into carbazole-9-thiocarbohydrazide in two steps. This compound was allowed to react with various electrophiles to yield 1,3,4-thiadiazole derivatives. The reaction with bifunctional electrophiles led to 1,3,4-thiadiazines. 2-(Carbazol-9-yl)-5,6-dihydro-4H-1,3,4-thiadiazin-5-one reacted with piperidine and formaldehyde to yield the 4-(piperidin-1-ylmethyl) derivative. The reaction with aromatic aldehydes led to the corresponding 6-arylidene derivatives, which were transformed into pyrimidino[4,5-e]-1,3,4-thiadiazines and pyrazolo[3,4-e]-1,3,4-thiadiazines by a reaction with guanidine, acetamidine, or phenylhydrazine, respectively. Structures of the products were confirmed by ¹H NMR, ¹³C NMR, IR, and mass spectrometric measurements. Selected examples of products were screened for anticancer activity.     

Synthesis,Characterization, and Antimicrobial Properties of New 1,3,4‐Thiadiazoles Derived from Azo Dyes

Some new 1,3,4‐thiadiazoles derived from azo dyes were synthesized. Two different synthesis methods were used for these compounds: Esters pertaining to the azo dyes were converted into 1,3,4‐thiadiazoles, or benzothiazole ester derivatives were converted to 1,3,4‐thiadiazoles followed by the synthesis of azo dye derivatives. The desired products were successfully obtained using the latter method. The molecular structures of these compounds were characterized using spectroscopic methods such as FTIR, ¹H NMR, ¹³C NMR, and elemental analysis. Furthermore, antimicrobial activity was studied for the synthesized compounds. Compound 3e exhibited antimicrobial activity against three different microorganisms. Compounds 3a , 3b , and 3d had activity against two different microorganisms, while compound 3c showed activity against only one microorganism.     

对苯二甲醛或间苯二甲醛与5，5-二甲基-1，3-环己二酮的反应：含有双4（日）-吡喃、1，4-二氢吡啶结构单元的杂环化合物的合成

用对苯二甲醛或间苯二甲醛与5，5-二甲基-1，3-环己二酮反应，在不同条件下得到了含有双4(H）-吡喃、1，4_二氢吡啶结构单元的双一氧杂蒽衍生物、双-吖啶衍生物、以及双-AL羟基吖啶衍生物．     

Uracyl derivatives functionalized with N-, S-, O-heterocycles

Reactions of 1,3-bis(bromopentyl)-5(6)-substituted uracyls with a series of five-membered heterocycles containing in the ring N, S, or O atoms and a mercapto group as a substituent at the carbon atom of the ring afforded uracyl derivatives of acyclic and macrocyclic structure with 2-thiobenzoxazole, 2-thio-5-methyl-1,3,4-thiadiazole, 2-thiobenzimidazole, and 2,5-dithio-1,3,4-thiadiazole fragments. N atoms of benzoxazole and imidazole fragments of compounds obtained undergo alkylation and quaternization with alkyl iodides and alkyl tosylates.     

Reaction of 4-Methylene-1,3-dioxolan-2-ones with Hydrazines

The structure of the products of the reaction of 4-methylene-1,3-dioxolan-2-ones with hydrazines is a function of the structure of the starting hydrazine. 1,3,4-Oxadiazin-2-one derivatives are obtained from hydrazine hydrate. 3-Arylaminooxazolidin-2-ones are obtained from monoarylhydrazines, while mixtures of these derivatives are obtained from aliphatic monoalkylhydrazines.     

Polynuclear nonfused bis(1,3,4-oxadiazole)-containing systems

Nonfused bis-1,3,4-oxadiazoles were synthesized by reaction of 5-substituted mono-and bis-tetrazoles with mono-and dicarboxylic acid chlorides. The results of kinetic studies showed that the transformation of tetrazoles into 1,3,4-oxadiazoles is accelerated by 1 to 2 orders of magnitude on addition of a catalytic amount of dimethylformamide, triethylamine, or pyridine.     

Synthesis, characterization, and biological activities of some 3,5,6-trichloropyridine derivatives

Aromatic carboxylic acids on refluxing with 3,5,6-trichloro-2-pyridyloxyacetylhydrazide in POCl3 gave 5-aryl-2-(3,5,6-trichloro-2-pyridyloxymethyl)-1,3,4-oxadiazoles. The hydrazide on treatment with acid chlorides gave diacylhydrazines, whereas with arylsulfonyl chlorides acyl(arylsulfonyl)hydrazines were obtained. The latter two types of compounds were tested for their antibacterial and antifungal activities whereas 1,3,4-oxadiazole derivatives were tested for their herbicidal activity. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 711–717, May, 2006.     

Four-Component Synthesis of Disubstituted 1,3,4-Oxadiazoles from N-Isocyaniminotriphenylphosphorane,Phenylacetylenecarboxylic Acid,Chloroacetone Derivatives,and Primary Amines

The 1:1 imine intermediate generated by the addition of primary amine to chloroacetone derivatives is trapped by N-isocyaniminotriphenylphosphorane in the presence of phenylacetylenecarboxylic acid, leading to the formation of the corresponding iminophosphorane intermediate. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at room temperature. The disubstituted 1,3,4-oxadiazole derivatives were prepared in excellent yields.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

具有生物活性的1,3,4-噻二唑并[3,2-a]-1,3,5-三嗪衍生物的合成方法

由1，3，4-噻二唑和1，3，5-三嗪稠合而成的1，3，4-噻二唑并[3，2．a]-1，3，5-三嗪衍生物具有广泛的生物活性，是一类重要的药用物质。本文对其在近二十年的合成方法进行了综述，重点介绍通过1，3，4-噻二唑衍生物为母体的合成方法。参考文献45篇。     

Hydrazones derived from thiooxamohydrazides and 3-formyl-4-hydroxycoumarin: synthesis, structures, and fragmentation

Novel hydrazones were obtained from thiooxamohydrazides and 3-3-formyl-4-hydroxycoumarin. According to data from NMR spectroscopy and X-ray diffraction, the coumarin fragment in the compounds obtained exists as 4-hydroxycoumarin or chromane-2,4-dione. When dissolved in dimethyl sulfoxide, these hydrazones undergo fragmentation into derivatives of 1,3,4-thiadiazole and 4-hydroxycoumarin.