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.

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

N1-acetylamino-(5-alkyl/aryl-1,3,4-thiadiazole-2-yl )-5-fluorouracil 衍生物的一个新系列被设计并且综合。这些混合物没在文学被报导，并且他们的结构化学药品被红外， 1H NMR 和 MS (HRMS ) 证实。antitumor 的结果禁止的活动测试证明一些混合物拥有更多的有势力 antitumor 禁止的活动比 5 氟尿嘧啶。

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.

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）.

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)?

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.

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.

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

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.

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.

5-芳基-1,3,4-噻二唑-2-胺衍生物的合成

在冰醋酸催化下,芳香醛(2a~2g)分别和氨基硫脲(3)反应合成得到芳亚胺基硫脲衍生物(4a~4g),中间体4无需经柱层析纯化,然后在三氯化铁作用下反应关环,得到7个目标化合物5-芳基-1,3,4-噻二唑-2-胺(1a~1g)。产物结构经^(1)H NMR、^(13)C NMR和ESI-MS确证。然后分别以中间体(E)-2-苄基肼-1-硫代酰胺(4a)和产物5-苯基-1,3,4-噻二唑-2-胺(1a)的合成为模型反应,考察了反应的主要影响因素,确定中间体4a合成的适宜条件为:n(氨基硫脲3)∶n(苯甲醛2a)=1.2∶1,在70℃下反应时间4 h;产物1a合成的适宜条件为:n(FeCl_(3))∶n(4a)=4∶1,在80℃下反应16 h。

Synthesis, Crystal Structure and Bioactivities of 1-(4-Chlorophenyl)-3-[5-(pyrid-4-yl)-1,3,4-thiadiazol-2-yl]urea

The title compound 1-（4-chlorophenyl）-3-[5-（pyrid-4-yl）-1,3,4-thiadiazol-2-yl]urea （C14H10CIN5OS, Mr = 331.79） has been synthesized by the reaction of 2-amino-5-（pyrid-4-yl）- 1,3,4-thiadiazole with 4-chlorobenzoyl azide, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic system, space group PI with a = 5.8550（8）, b = 7.5668（10）, c = 16.416（2）A, α= 78.364（2）, β= 81.204（2）, γ= 84.749（2）°, V= 702.58（16）A^3, Z= 2, Dc = 1.568 g/cm^3, p = 0.429 mm ^-1, F（000） = 340, the final R = 0.0442 and wR = 0.1092 for 2001 observed reflections （1 〉 2σ（I））. X-ray diffraction analysis reveals that the title molecule is nearly planar. In the crystal structure, the molecules are linked by strong intermolecular N-H…N hydrogen bonds together with weak nonclassical intennolccular （C-H…Y, Y = N, O and CI） hydrogen bonds and stacked through π-π interactions. The preliminary bioassay shows that the title compound exhibits good fungicidal activities against Rhizoctonia solani, Botrytis cinerea and Dothiorella gregaria.

Synthesis, Crystal Structure and Antitumor Activity of N-(5-Aryl-1,3,4-thiadiazol-2-yl)-N?-((E)-styryl)ureas

N-(5-Aryl-1,3,4-thiadiazol-2-yl)-N?-((E)-styryl)ureas 4 a^4 i were designed and synthesized as antitumor agents, and their structures were characterized by IR, 1 H NMR, 13 C NMR,MS and elemental analysis. The single crystal of compound 4 a, C17 H13 FN4 OS, was also determined by X-ray crystallography. Crystal data: monoclinic, space group P21/n, a = 4.9401(8), b= 8.7100(15), c = 36.604(6) A,β= 93.320(3)°, V = 1572.4(5) A3, Z = 4, F(000)= 704, Dc = 1.438 g/cm3,μ= 0.228 mm-1, R = 0.0600 and wR = 0.1448 for 2743 independent reflections(Rint =0.0418) and 2174 observed ones(I > 2σ(I)). The in vitro antitumor activities of compounds 4 a^4 i were preliminarily evaluated by the standard MTT assay.

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.

吡啶衍生物研究(Ⅷ):2-[(2-氯吡啶)-4-基]-5-烷氨基-1,3,4-噻二唑的合成及其除草活性

为寻找新的农药先导化合物 ,依据活性亚结构拼接原理 ,以异烟酸为起始原料 ,共合成了 12个标题化合物 ,其结构通过元素分析、1H和13 CNMR予以确认。所有化合物均具有一定的除草活性 ,且茎叶处理高于土壤处理 ,其中Ⅰ 0 4和Ⅰ 0 6在 1 5kg·hm-2 剂量下 ,茎叶处理对反枝苋、稗草、油菜和苜蓿的抑制率分别达 71 9%～89 2 %和 4 5 3%～ 87 0 % ;因此 。

吡啶衍生物研究(X):2-仲丁氨基-5-(2-芳氧吡啶-4-基)-1,3,4-噻二唑的合成及除草活性

为了研究2-仲丁氨基-5-（2-氯吡啶-4-基）-1,3,4-噻二唑（BCPT）的结构-活性关系和开发活性更高的新型除草剂,以BCPT为先导化合物,依据活性亚结构连接法,在吡啶环2-位上引入二芳醚类除草剂的典型结构单元——芳醚,设计并合成了一系列新的芳氧吡啶噻二唑类化合物,其结构经元素分析和^1H NMR确证。初步除草活性测定结果表明,在500mg/L剂量下,所有化合物的除草活性（抑制率0-45%）远低于先导化合物（抑制率72%-87%）,说明吡啶环2-位上的氯原子可能对维持该类化合物的除草活性是必需的。