3,6-二取代苯基-二-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑衍生物的合成

以2,5-二巯基-1,3,4-噻二唑为原料, 与水合肼缩合, 生成2,5-二肼基-1,3,4-噻二唑. 2,5-二肼基-1,3,4-噻二唑与苯甲酰氯反应生成2,5-二酰肼基-1,3,4-噻二唑, 以POCl₃为环合剂环合酰肼基-1,3,4-噻二唑, 合成3,6-二取代苯基- 二-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑衍生物, 合成的新化合物的结构通过元素分析、红外光谱、核磁共振氢谱和质谱予以证实, 并提出了环化反应机理.     

2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑的合成

通过对称双酰肼与P_2S_5的缩合反应合成2,5-二-羟苯基-1,3,4-噻二唑,并由此制备了2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑及其相关化合物,同时测定了它们的生物活性。     

2,5-二乙氧甲酰氨基-1,3,4-噻二唑超分子化合物的合成和晶体结构

报道了一种用1,6-二取代二硫脲在DMF中加热回流直接脱H₂S关环合成2,5-二取代1,3,4-噻二唑类化合物的新方法, 并用此方法合成了2,5-二乙氧甲酰氨基-1,3,4-噻二唑. 用元素分析、核磁共振氢谱、红外光谱进行了表征, 用X射线单晶衍射法确定了其单晶结构. 晶体属单斜晶系, P2₁/c空间群, a＝1.0093(4) nm, b＝0.9035(4) nm, c＝1.2924(6) nm, β＝96.785(9)°, V＝1.1703(9) nm³, Z＝4, D_c＝1.477 g/cm³, F(000)＝544, μ＝0.287 mm^－1. 该化合物通过分子间氢键形成了一种二维网状结构的超分子, 由于分子间的作用力使其分子又沿c轴呈层状堆积.     

2，5-二（取代胺基甲酰基甲硫基）-1，3，4-噻二唑的合成与表征

以2.5-二巯基-1,3,4-噻二唑和N-取代氯乙酰胺为原料,合成了12种2,5-二(取代胺基甲酰基甲硫基)-1,3,4-噻二唑(3a-31),收率33.5%-88.0%,其结构经1H NMR,13C NMR,IR和元素分析表征.3的荧光测试结果表明,其中5种具有良好的荧光性质;电化学测试结果表明,3f有一对氧化还原峰.     

芳醛-[5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑-2-巯基]-乙酰腙衍生物的合成及生物活性研究

采用活性基团拼接法, 以2-巯基-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑为原料, 经硫醚化、肼解、腙化反应合成了8个芳醛-[5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑-2-巯基]-乙酰腙衍生物, 并经过元素分析, IR, ¹H NMR, ¹³C NMR对其结构进行了确认. 初步生物活性测试表明, 部分化合物具有一定的抑菌生物活性.     

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.     

2,5-二芳基-噻二唑的合成及其缓蚀性能研究

合成了四种噻二唑衍生物:2,5-二苯基-1,3,4-噻二唑(DPTD),2,5-二(2-羟基苯)-1,3,4-噻二唑(2-DHPTD),2,5-二(3-羟基苯)-1,3,4-噻二唑(3-DHPTD)和2,5-二(4-羟基苯)-1,3,4-噻二唑(4-DHPTD)。采用Tafel极化测试、电化学阻抗谱(EIS)和扫描电子显微镜(SEM)研究了噻二唑衍生物在50 mg·L-1硫-乙醇体系中对银的缓蚀作用。实验结果表明:添加缓蚀剂后,银片腐蚀得到抑制,且缓蚀效率大小顺序为:[DPDT][2-DHPDT][3-DHPDT][4-DHPDT]。通过量子化学计算和分子动力学模拟进一步研究了四种噻二唑衍生物的缓蚀机理,理论计算结果与实验结果一致。     

超声辐射下合成1-[(未)取代苯酰基-3-[5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑-2-基]-硫脲

1-苯基-3-甲基-5-氯吡唑-4-甲酸与氨基硫脲在三氯氧磷中反应得到2-氨基-5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑(1), 然后分别采用超声辐射法和常规加热法与(未)取代苯甲酰基异硫氰酸酯(2)反应合成了一系列未见报到的1-[(未)取代苯酰基-3-[5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑-2-基]-硫脲(3a～3j). 化合物的结构经元素分析, IR, ¹H NMR确证.     

2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4- 噻唑啉酮的合成

以2-氨基-5-取代苯氧甲基-1,3,4-噻二唑(1)为起始原料, 合成了中间体2-氯乙酰氨基-5-取代苯氧甲基-1,3,4-噻二唑)-2-乙酰亚胺(2)和2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-4-噻唑啉酮(3), 化合物3进一步与取代苯甲醛发生类Knoevenagle缩合反应, 得到了一系列2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4-噻唑啉酮类化合物4a～4p. 目标化合物4a～4p的结构经IR, ¹H NMR和元素分析确证.     

1,3-双[3-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑-6-基]丙烷类化合物的合成

戊二酸(1)与3-芳基-4-氨基-5-巯基-1,2,4-三唑(2a～2o)在相转移催化剂四丁基碘化铵和POCl₃作用下, 高收率合成了一系列新的1,2-双[3-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑-6-基]丙烷(3a～3o). 其结构经IR, ¹H NMR, MS和元素分析确证.     

Synthesis and characterization of new polyhydrazides based on 2,5-bis(mercapto-acetichydrazide)-1,3,4-thiadiazole moiety

New interesting class of novel polyhydrazides containing 1,3,4-thiadiazole moieties in the main chain was synthesized. A solution polycondensation technique was used in the synthesis of these polymers. The new monomer namely: 2,5-bis(mercapto-acetichydrazide)-1,3,4-thiadiazole III was synthesized from the nucleophilic replacement of 2,5-dimercapto-1,3,5-thiadiazole I with ethylchloroacetate, followed by hydrazinolysis. The model compound VII was synthesized from the monomer 2,5-bis(mercapto-acetichydrazide)-1,3,4-thiadiazole III with benzoyl chloride and characterized by ¹H- NMR, IR, and elemental analyses. The polyhydrazides were synthesized from the polymerization of monomer III with 4,4^′-biphenic, 3,3^′-azodibenzoyl, 4,4^′-azodibenzoyl dichlorides. These polymers were characterized by elemental and spectral analyses, viscometry and solubility. The thermal properties of these polymers were determined by thermal gravimetric analyses, and differential thermal analysis, and correlated with their structure. The crystallinity of some polymers was tested by X-ray analyses.     

Synthesis and reactivity of acyclic and macrocyclic uracils bridged with five-membered heterocycles

Replacement of terminal atoms of Br in 1,3-bis(bromopentyl)-5(6)-substituted uracils with 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptoimidazole, and 2-mercaptobenzimidazoles resulted in a series of acyclic compounds and isomeric heterocyclophanes. Structures of macrocyclic regioisomers were unambiguously determined by NMR data. One of the regioisomers exhibits a hypochromic effect with respect to model compounds. The acyclic uracils obtained bridged with five-membered heterocycles are alkylated with methyliodide and methyl tosylate, and oxidated with m-CPBA, H₂O₂, and I₂.     

Thermotropic liquid crystalline polymers containing five-membered heterocyclic groups VIII. Synthesis,and liquid crystalline and photoluminescent properties of semi-rigid polyesters based on a distyrylbenzene analogue of 1,3,4-thiadiazole

New semi-rigid polyesters composed of the distyrylbenzene analogue of 1,3,4-thiadiazole, 2,5-bis(2-phenylethenyl)-1,3,4-thiadiazole and aliphatic (dodeca-, deca- and octamethylene) chains were prepared by high temperature solution polycondensation; their liquid crystalline (LC) and photoluminescent properties were investigated. Differential scanning calorimetry, polarizing microscopy and powder X-ray diffraction show that the polyesters having both dodeca- and decamethylene chains form a thermotropic smectic C phase and a lyotropic LC phase in trifluoroacetic acid, but the polyester containing octamethylene chains only exhibits a thermotropic smectic C phase. Solution and solid state absorption and fluorescent spectra indicate that all the polyesters in this work display absorption maxima based on the 2,5-bis(2-phenylethenyl)-1,3,4-thiadiazole moiety, emitting blue light in HFIP solutions and bluish-green light in solids; the Stokes shifts are 80.1-80.7 nm in solution and 74.2-87.2 nm in the solid state.     

Thermotropic liquid crystalline polymers containing five-membered heterocyclic groups VIII. Synthesis, and liquid crystalline and photoluminescent properties of semi-rigid polyesters based on a distyrylbenzene analogue of 1,3,4-thiadiazole

New semi-rigid polyesters composed of the distyrylbenzene analogue of 1,3,4-thiadiazole, 2,5-bis(2-phenylethenyl)-1,3,4-thiadiazole and aliphatic (dodeca-, deca- and octamethylene) chains were prepared by high temperature solution polycondensation; their liquid crystalline (LC) and photoluminescent properties were investigated. Differential scanning calorimetry, polarizing microscopy and powder X-ray diffraction show that the polyesters having both dodeca- and decamethylene chains form a thermotropic smectic C phase and a lyotropic LC phase in trifluoroacetic acid, but the polyester containing octamethylene chains only exhibits a thermotropic smectic C phase. Solution and solid state absorption and fluorescent spectra indicate that all the polyesters in this work display absorption maxima based on the 2,5-bis(2-phenylethenyl)-1,3,4-thiadiazole moiety, emitting blue light in HFIP solutions and bluish-green light in solids; the Stokes shifts are 80.1-80.7 nm in solution and 74.2-87.2 nm in the solid state.     

Synthesis and comparative study of the heterocyclic rings on liquid crystalline properties of 2,5-aryl-1,3,4-oxa(thia)diazole derivatives containing furan and thiophene units

A series of heterocyclic liquid crystalline compounds containing 1,3,4-oxadiazole/thiadiazole, furan and thiophene units were synthesised and characterised by means of electrospray ionisation-mass spectrometry (ESI-MS), high-resolution mass spectroscopy (HRMS), ¹H nuclear magnetic resonance (NMR) and ¹³C NMR. The thermal behaviours were investigated by differential scanning calorimetry (DSC) and polarised optical microscopy (POM). The effect of the 1,3,4-oxadiazole, 1,3,4-thiadiazole, furan, thiophene and benzene rings on the liquid crystalline properties was discussed briefly in context with the geometrical and electronic factors. The results showed that the tendency to form mesophases follows the sequence: 1,4-disustituted benzene >2,5-disubstituted thiophene >2,5-disustituted furan and 1,3,4-thiadiazole >1,3,4-oxadiazole.     

Synthesis and properties of diaminothiadiazoles

Refined synthetic procedure for preparation of 3,5-diamino-1,2,4-thiadiazole and 2,5-diamino-1,3,4-thiadiazole based on the reaction of dithiourea or amidinothiourea with hydrogen peroxide is developed. The optimal reagents ratio was found, and monitoring methods were developed. It resulted in the increase of the target product yield and in a shorter reaction time. On the basis of 2,5-diamino-1,3,4-thiadiazole the alkylsubstituted 1,3,4-diaminothiadiazolidines were synthesized. The compounds prepared were characterized by the elemental analysis data, the IR, ¹H NMR, and electronic spectra, and also by mass spectrometry.     

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 1,3,4-thiadiazol-2,5-dithiol with <Emphasis Type="Italic">N</Emphasis>-acryloyl-substituted derivatives of several alkaloids

Potentially bioactive 2,5-bis derivatives of 1,3,4-thiadiazole with alkaloid moieties were synthesized by reaction of 1,3,4-thiadiazol-2,5-dithiol with N-acryloyl-substituted derivatives of the alkaloids anabasine, cytisine, and D-pseudoephedrine.     

N-H?S hydrogen bonding in 2-mercapto-5-methyl-1,3,4-thiadiazole. Synthesis and crystal structures of mercapto functionalised 1,3,4-thiadiazoles

The synthesis and crystal structures of three mercapto functionalised 1,3,4-thiadiazoles and the crystal structure of 2-mercapto-5-methyl-1,3,4-thiadiazole are described. In the solid state, 2-mercapto-5-methyl-1,3,4-thiadiazole 1 forms a thioamide tautomer as shown by FTIR and Raman spectroscopy as well as X-ray crystallography and as theoretically predicted. The molecules are connected to form chains via N-H?S hydrogen bonds with N?S=328.3 pm. Bis(2-methyl-1,3,4-thiadiazolyl)-5,5′-disulfide 2, the disulfide of 1, as well as 2-(tert-butyldithio)-5-methyl-1,3,4-thiadiazole 3 and 2,5-bis(tert-butyldithio)-1,3,4-thiadiazole 4 have been synthesised and characterised by vibrational spectroscopy and X-ray diffraction.     

Solid phase synthesis of an extensively focused library of thiadiazole ethers

An approach to combine the advantages of random and of focused combinatorial libraries in pharmaceutical research is described with the example of a solid phase synthesis of 2,5-disubstituted thiadiazole ethers. Key steps of synthesis are the introduction of the heterocycle by selective, sequential nucleophilic double substitution of 2,5-bis(methylsulfonyl)-1,3,4-thiadiazole and the oxidation of the benzylsulfanyl-1,3,4-thiadiazole to the corresponding sulfone using MCPBA on solid phase.