2,5-Dimercapto-1,3,4-Thiadiazole(DMCT)-Based Polymers for Rechargeable Metal-Sulfur Batteries

Organosulfur materials are a sustainable alternative to the present-day layered oxide cathodes in lithium-based batteries.One such organosulfur material that was intensely explored from the 1990s to early 2010s is 2,5-dimercapto-1,3,4-thiadiazole(DMCT).However,research interest declined as the electrode reactions with DMCT were assumed to be too sluggish to be practical.Armed with the advances in metal-sulfur batteries,we revisit DMCT-based materials in the form of poly[tetrathio-2,5-(1,3,4-thiadiazole)],referred to as pDMCT-S.With an appropriate choice of electrode design and electrolyte,pDMCT-S cathode paired with a Li-metal anode shows a capacity of 715 mA h g^(-1)and a Coulombic efficiency of 97.7%at a C/10 rate,thus quelling the concerns of sluggish reactions.Surprisingly,pDMCT-S shows significantly improved long-term cyclability compared to a sulfur cathode.Investigations into the origin of the stability reveals that the discharge product Li-DMCT in its mesomeric form can strongly bind to polysulfides,preventing their dissolution into the electrolyte and shuttling.This unique mechanism solves a critical problem faced by sulfur cathodes.Encouragingly,this mechanism results in a stable performance of pDMCT-S with Na-metal cells as well.This study opens the potential for exploring other organic materials that have inherent polysulfide sequestering capabilities,enabling long-life metal-sulfur batteries.

Synthesis,Characterization and Crystal Structure of 3-o-Fluorophenyl-6-(4-decarboxydehydroabietyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole

Three novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles were designed,synthesized and characterized by IR,NMR and APCI-MS.3-o-Fluorophenyl-6-（4-decarboxydehydroabietyl）-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole（6a,C28H31FN4S） was structurally determined by single-crystal X-ray diffraction.The crystal belongs to the orthorhombic system,space group P212121 with a=6.0153（14）,b=12.2577（19）,c=34.055（3）A,V=2511.0（7）A^3,Z=4,Mr=474.63,Dc=1.255Mg/m^3,λ=0.71073 A,μ（MoKα）=0.160 mm^-1,F（000）=1008,the final R=0.0555 and wR=0.1248 for 3094 observed reflections with I〉2σ（I）.There are six rings in the crystal structure of the title compound.The dihedral angle between 1,2,4-triazole and 1,3,4-thiadiaole rings is 1.4o,and that between 1,2,4-triazole and benzene ring D 25.5o.

Synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with potential bioactivity in PEG-400

An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.

Microwave Assistant Synthesis and Dimeric Crystal Structure of 2-(((6-Chloropyridin-3-yl)-methyl)thio)-5-(pyridin-4-yl)-1,3,4-thiadiazole

The title compound 2-(((6-chloropyridin-3-yl)methyl)thio)-5-(pyridin-4-yl)-1,3,4-thiadiazole 5(C26H18Cl2N8S4) was synthesized, and its structure was confirmed by 1H NMR, MS and elemental analyses and X-ray diffraction. It crystallizes in the triclinic system, space group P1 with a = 9.452(4), b = 12.335(4), c = 13.017(5) A, α = 90.624(5), β = 110.541(5), γ =104.879(4)°, Dc = 1.561 g/cm3, Z = 2, V = 1364.9(9) A3, F(000) = 656, the final R = 0.0300 and w R = 0.0635 for 4206 observed reflections with I 】 2σ(I). The preliminary biological test showed that the title compound has activities against Stemphylium lycopersici(Enjoji) Yamamoto, Fusarium oxysporum. sp. cucumebrium, and Botrytis cinerea with inhibitory activities to be 9.82%, 44.44% and 20.00%, respectively.

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

The crystal structure of the title compound, 2-isobutyl-6-(2?4?dichlorophenyl)- imidazo[2,1-b]-1,3,4-thiadiazole (C14H13Cl2N3S, Mr = 326.23), has been synthesized by the treatment of 2-amino-5-isobutyl-1,3,4-thiadiazole with a-chloroaceto-2,4-dichlorophenone and determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 12.483(7), b = 8.420(4), c = 14.998(8) ? b = 105.770(10)? V = 1517.0(14) 3, Z = 4, Dc = 1.428 g/cm3, S = 0.902, m(MoKa) = 0.558 mm-1, F (000) = 672, R = 0.0579 and wR = 0.1186. The X-ray analytic results showed that all ring atoms in the imidazothiadiazole moiety are almost coplanar. The dihedral angel between the phenyl group and hetero-cycle is 16.8(0.2)?

Synthesis and antitumor activity of N^1-acetylamino-(5-alkyl/aryl-1,3,4-thiadiazole-2-yl)-5-fluorouracil derivatives

A new series of N^1-acetylamino-（5-alkyl/aryl- 1,3,4-thiadiazole-2-yl）-5-fluorouracil derivatives were designed and synthesized. These compounds have not been reported in literature, and their structure chemical were confirmed by IR, ^1H NMR and MS （HRMS）. The results of antitumor inhibitory activity test showed that some compounds possess more potent antitumor inhibitory activity than 5-fluorouracil.

Synthesis and Tribological Behaviour of 1,3,4-Thiadiazole Schiff Base Derivatives as Multifunctional Lubricant Additives

Six new 1,3,4-thiadiazole Schiff base derivatives were synthesized and characterized by IR spectroscopy and ~1H NMR spectrometry, and their anti-corrosion properties and thermal stability were investigated via thermogravimetric analysis(TGA) and copper strip corrosion test. The tribological behavior of the said Schiff base derivatives was evaluated on an Optimol SRV~?4 oscillating reciprocating friction and wear tester. The worn surfaces of the steel discs were investigated using a scanning electron microscope(SEM) and energy dispersive X-ray spectrometer(EDS). The test results indicated that these thiadiazole Schiff base derivatives possessed favourable thermal stability, corrosion inhibiting ability and the capability of improving the tribological characteristic of the base oil effectively. It is assumed that the adsorbed additives probably reacted with the steel surfaces during the friction process, resulting in the formation of a protective film composed of sulphates, sulphides and organic nitrogen compounds.

New Fungicidally Active Pyrazolyl-Substituted 1,3,4-Thiadiazole Compounds and Their Preparation

The potassium dithiocarbazate 2 was obtained through condensation of 5-pyrazole hydrazide 1 with carbon disulfide in ethanolic potassium hydroxide. and its cyclization gave 5-pyrazolyl-1,3,4-thiadiazole-2-thione 3 in concentrated sulfuric acid. Alkylation of 3 yielded 2-alkylthio-5-pyrazolyl-1,3,4-thiadiazole 4. The preliminary bioassay tests indicated that compounds 3 and 4 have fungicidal activity.

One-pot synthesis of 2,5-disubstituted-1,3,4-thiadiazoles under ultrasonic irradiation

A facile one-pot synthesis of 2,5-disubstituted-1,3,4-thiadiazoles was achieved by ultrasonic irradiation of a mixture of 1-naphthylacetyl chloride, NH4CNS, CH2Cl2 and PEG-400 for 1.5 h at 10–20 °C and subsequent irradiation for 1.5 h in the presence of N-arylglycine hydrazides. This method requires short time and gives thiadiazoles in high yields.

A novel series of 2,5-disubstituted 1,3,4-thiadiazoles as potential anticonvulsant agent

In pursuit for better antiepileptic drug and the importance of semicarbazones and 2,5-disubstituted 1,3,4-thiadiazoles as anticonvulsant pharmacophore, a series of novel N-（{5-[（6-methyl-l-benzofuran-3-yl）methyl]-l,3,4-thiadiazol-2-yl}carba- mothioyl）-2/3/4-substitutedbenzamide were designed, synthesized and evaluated for their anticonvulsant activity. The findings of the present studies confirmed that the pharmacophore model with four binding sites is crucial for anticonvulsant activity. Structure-activity relationships among synthesized compounds were also established.

One-dimensional Zigzag Chain Composed of HgI_2 Unit and 2,5-Bis(4-pyridyl)-1,3,4-thiadiazole:[HgI_2(C_(12)H_8N_4S)]

The title compound, [HgI2（C12H8N4S）], has been synthesized and characterized by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 14.086（2）, b = 6.0365（6）, c = 20.286（2）°A,β= 108.818（5）°, V = 1632.7（3）°A^3, Mr = 694.67, Z = 4, D, = 2.826 g/cm^3,μ= 13.331 mm^-1, F（000） = 1240, S = 1.108, the final R = 0.0438 and wR = 0.0934 for 3085 observed reflections （I〉 2σ（I））. The Hg（Ⅱ） atom is coordinated by two 2,5-bis（4-pyridyl）-1,3,4-thiadiazole （L） molecules and two iodine anions in a distorted tetrahedral coordination geometry. Mercury atoms are linked by the organic ligands to form a one-dimensional zigzag chain. It is noteworthy that such 1D zigzag chains are extended into a two-dimensional double layer framework through I…I interactions

Syntheses and Crystal Structures of Two Novel Cobalt(Ⅱ) Complexes with 2-Amino-5-substituted-1,3,4-thiadiazole as Ligands

Two novel cobalt（Ⅱ） compounds were obtained and characterized by X-ray sing- le-crystal diffraction, IR, 1H NMR and elemental analysis. Compound 1 crystallizes in monoclinic, space group P21/n, with a = 18.046（4）, b = 11.335（3）, c = 19.157（5）A, β = 92.707（3）°, Z = 4, V = 3914.4（16） A3, Mr = 968.56, Dc = 1.644 g/cm3, μ = 1.378 mm^-1, F（000） = 1960, the final R = 0.0367 and wR = 0.0895. The crystal of compound 2 is of monoclinic, space group P211c with a = 8.7253（10）, b = 10.9031（13）, c = 18.235（2）A,β = 93.2210（10）°, Z = 4, V = 1732.0（3）A3, Mr = 464.21, Dc = 1.780 g/cm3,μ = 1.560 mm-1, F（000） = 932, the final R = 0.0322 and wR = 0.0743.

Studies on Condensed Heterocyclic Compounds(Ⅲ)——Synthesis and Antibacterial Activity of 3-(4-Pyridyl)-6-Alkyl/Aromatic Heterocyclyl-s-Triazolo[3,4-b]-1, 3,4-Thiadiazoles and 1,4-Bis [6-(4-Pyridyl)-s-Triazolo [3,4-b]-1, 3,4-Thiadiazol-3-yl]-n-Butane

In recent years, fused heterocycles have been reported to possess important properties in synthesis and pharmacology. Especially, s-triazolo, 3,4-thiadiazole derivatives have been attracting much attention for chemists and pharmacologists because they show broad spectra of biological activities, such as antifungal, antibacterial, hy-

Anti-tumor Metastasis and Crystal Structure of N^1-(1,3,4-Thiadiazole-2-yl)-N^3-m-chlorobenzoyl-urea

The title compound N1-（1,3,4-thiadiazole-2-yl）-N3-m-chlorobenzoyl-urea （C9HTN4OSC1, Mr = 254.70） was prepared by the reaction of m-chlorophenyl isocyanate with 2-amino-1,3,4- thiadiazole in dry acetonitrile. The effect of the title compound on tumor metastasis was analyzed by Lewis-lung-carcinoma model. The bioassay showed that the title compound significantly reduced the number of lung metastasis. The crystal structure has been determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 11.565（2）, b = 9.5616（19）, c = 10.221（2） A, β = 111.75（3）°, Z = 4, V= 1049.8（4） A3, De = 1.612 Mg/m3, F（000） = 520, g（MoKa） = 0.544 mm^-1, R = 0.0468 and wR = 0.0922 for 1236 observed reflections （I〉 2σ（I）.

Synthesis, Characterization and Crystal Structure of a Dinuclear Silver(I) Complex: [AgL(NO_3)]_2 (L= 2-Acetamido-5-methyl-1,3,4-thiadiazole)

The title complex [AgL（NO3）]2 1, where L = 2-acetamido-5-methyl-1,3,4-thiadiazole, was prepared from the reaction of 2-acetamido-5-methyl-1,3,4-thiadiazole with AgNO3 at room temperature and its structure has been determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P2t/c with a = 12.5454（8）, b = 11.9672（12）, c = 6.8925（6） A, β = 98.468（2）°. V= 1023.51（15） A^3, Mr= 3127.08, Dc = 2.123 g/cm^3, Z= 4, μ（MoKoσ） = 2.174 mm^-1, F（000） = 640, R = 0.0259 and wR = 0.0580 for 1787 observed reflections with I 〉 2σ（I）. Complex 1 self-assembls into a quasi-three-dimensional network consisting of adjacent dimers through intermolecular Ag...O weak interactions.

Studies on Amidothiosemicarbazides and Related Hcterocyclic Derivatives ( XIII) --Synthetic Studies on 2-(3-Pyridyl)-5-Arylamino- 1,3, 4-Thiadiazoles and Oxadiazoles

By ring-closure of 1-nicotinyl-4-arylthiosemicarbazides under the catalysis of concentrated sulfuric acid or mercuric acetate, a series of 2-(3-pyridyl)-5-arylarnino-1,3,4-thiadiazoles and 2-(3-pyridyl)-5-ary-lamino-1,3,4-oxadiazoles were synthesized, respectively. All the products were subjected to testing of biological activity. Furthermore, the IR, 1H NMR and MS spectral properties of these new compounds were studied in details and some significant conclusions were drawn.

Synthesis, Crystal Structure and Fungicidal Activity of 3-(4-Chloro-3-ethyl-1-methyl-1H-pyrazol-5-yl)-6-(E)phenylvinyltriazolo[3,4-b]-1,3,4-thiadiazole

The crystal structure of the title compound 3 (4 Chloro 3 ethyl 1 methyl 1H pyrazol 5 yl) 6 (E)phenylvinyltriazolo[3,4 b] 1,3,4 thiadiazole (C 17 H 15 ClN 6S, M r =370.87) was determined by single crystal X ray diffraction. The crystal is monoclinic, space group P2 1/n , a=10.862(2), b=11.541(2), c=14\^994(3), β=108.41(3)°, V=1783(1), Z=4, D x =1.381 g/cm -3 , μ =0.3361 mm -1 , and F (000)=768. The results confirmed that the title compound belongs to type E of stereochemistry. The dihedral angle between triazole and 1,3,4 thiadiaole ring is 3° and the torsion angle between 1,3,4 thiadiazole and pyrazole ring is 134.0°.

微波促进下3-(2-苯并呋喃基)-4-氨基-5-巯基-1,2,4-三唑及其衍生物的合成

微波辐射条件下,首先由2-苯并呋喃甲酰肼依次与二硫化碳和水合肼反应合成3-(2-苯并呋喃基)-4-氨基-5-巯基-1,2,4-三唑,进一步在微波辐射条件下由4-氨基-5-巯基-1,2,4-三唑分别与芳甲酸/芳氧基乙酸、α-溴代苯乙酮及芳醛反应以较高产率制得了相应的1,2,4-三唑并[3,4-b]-1,3,4-噻二唑、1,2,4-三唑并[3,4-b]-1,3,4-噻二嗪及4-芳亚甲基亚胺基-5-巯基-1,2,4-三唑.产物结构经IR,1HNMR,MS及元素分析进行了表征.

1,3,4-[口恶]二唑类化合物的合成及生物活性研究进展

1,3,4-[口恶]二唑是一类重要的含氮五元芳香杂环类结构单元,可与多种药效团融合,产生不同的生物活性,因此引起了人们的关注,也显示了广泛的应用和发展前景,在医药和农药领域尤为突出。综述了国内外以酰肼环合法、Huisgen反应高效构建1,3,4-[口恶]二唑类化合物的方法,同时对1,3,4-[口恶]二唑类化合物在抗病毒、抗菌、抗肿瘤、除草、杀虫等方面的生物活性进行了介绍,并对各类化合物的构效关系进行总结,为进一步研究1,3,4-[口恶]二唑类化合物的设计合成及其生物活性提供参考和借鉴。

探索性有机化学实验教学——以2-氨基-5-乙基-1,3,4-噻二唑的合成为例

有机化学实验是制药工程专业重要的基础课之一,既是对有机化学理论课的补充,又是学习药学专业课的基础。本文以氨基硫脲和丙醛为原料,通过改变溶剂、氧化剂种类、反应温度、反应时间及反应物投料比筛选出最优反应条件,从而提高2-氨基-5-乙基-1,3,4-噻二唑的产率。通过本次实验,不仅有利于学生巩固理论知识,提高实验动手能力,培养学生热爱化学,热爱科研,激发探索性思维具有重要的作用。