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.     

Synthesis of novel herbicidal sulfonylureas

Novel sulfonylurea derivatives containing flve-membered hete-rocycle 3a-1 and 4a-d were synthesized in good yields by the regioselective addition of aryl sulfonylisocyanates 1 to 5-amino-3-benzyl (aryl) thio-1, 2, 4-triazoles and its pyrazole analogues 2. The structures of all these compounds were evaluated by elemental analyses and 1H NMR spectroscopy. The preliminary biological tests showed that the products displayed herbiddal activity against rape to some extent.     

The Chlorination of O-Alkyl S-Alkyl(aryl) Thiophosphoric(-nic) Acid Derivatives with Phosphorus Oxychloride——A New Convenient Method for Synthesis of Chiral S-Alkyl(aryl) Thiophosphoro(-no) Chloridates

In our laboratory, the isomerization/chlorination of a variety of O,O-dialkyl phosphoro(-no)thionates 1 with phosphorus oxychloride have been systematically studied. It was found that when R' equals aryloxy^[1], alkylthio^[2], arylthio^[2], dialkylamino^[3], phenyl^[4], methyl^[5],and nitrogen heterocyclic group^[6] in 1,respectively, this reaction can proceed smoothly and gives the desired products ² and ³. Hence, it provides a general synthitic method for S-alkyl thiophosphoro(-no)chloridates, especially for the asymmetric ones.     

Two New Alkaline Metal Borates with Supramolecular Framework Constructed from 1D {B5}/{B6} Helical Chains

Two new alkaline metal borates containing 1D{B5}/{B6}oxoboron helical chains,namely Na0.5[B5O8(OH)2]0.5[B5O6(OH)2]0.5·0.5H3O(1)and NaKCs[B6O9(OH)3](2)were synthesized under solvothermal conditions.Compound 1 contains the interesting alternative left-and right-handed helical{[B5O8(OH)2][B5O6(OH)2]}2-({B5}-1 and{B5}-2)1D chains and compound 2 possesses the similar[B6O11(OH)3]7-({B6})chains.Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds.In addition,the UV cutoff edge of compounds 1 and 2 is both below 190 nm.     

Synthesis of 6-(1-Aryl-5-methyl-1,2,3-triazol-4-yl)-3-(4-Pyridyl)-s-Triazolo[3,4-b]-l,3,4-Thiadiazoles

A survey of literature¹ revealed that s-triazolo[3,4-b]-1,3,4-thiadiazole, an interesting fused system of s-triazole and 1,3,4-thiadiazole rings, has received much attention during recent years on account of its prominent utilizations as antifungal, antiinflammatory, antiviral, analgesic and anthelmintic agents probably resulting from its planner and compact structure. Our earlier work on the synthesis of this class of heterocycles showed antibacterial, herbicidal and plant growth regulative properties^2-3 for the compounds. 1,2,3-Triazole derivatives have found their wide use in medicine, agriculture and industry^4-5. Incorporation of 1,2,3-triazole moiety into the 6-position of this ring system may lead to achieving compounds of better biological activities. In view of the above findings coupled with scanty reports on these condensed compounds carrying 6-heterocyclic groups, we wish to report here the condensation of 4-amino-5-mercapto-3-(4-pyridyl)-l,2,4-triazole(2) with 1-aryl-4-carboxy-5-methyl-1,2,3-triazoles(1_a-j) as a part of our continuing interest in this area.     

Unexpected Products from the Reaction of Naphthols with Cholesterol Catalysed by Montmorillonite K 10

Under catalysis of montmorillonites, arenes could be cholesterylated by cholesterol (1) via a Friedel-Crafts alkylation.¹ When phenols were employed as substrates for that reaction, aryl cholesteryl ethers were obtained instead of aryl cholestenes.² However, β-naphthol (2a) and α-naphthol (2b) gave obviously different products. We report here the identification of these unexpected products from the reaction of 2 with 1 catalysed by montmorillonite K 10.     

First Total Synthesis of (±)-Ponganone Ⅲ

In recent years, the synthesis and pharmacology of pyranoflavanoids have been extensively investigated due to their wide range of pharmacological properties^[1-3]. Ponganone Ⅲ^[4],a new natural pyranoflavanone isolated from the Pongamia pinnala, was identified as (2S)-3',4'-dimethoxy-6',6"-dimethylpyrano-[2",3":7,8]-flavanone (2) on the basis of spectra data. Its precursor,3,4-dimethoxy-2'-hydroxy-6",6"-dimethylchromeno-[2",3":4',3']-chalcone (1) is also a new natural product^[5] isolated from the roots of Lonchocarpus subglaucescent. Their total synthesis have not been reported. Herein, we wish to report the first total synthesis of compounds 1 and 2 in order to confirm the proposed structure and further more to evaluate its biological activities.     

Pyrazolo[1, 2-a]pyrazoliumolates as novel structure elements in liquid crystals [1]

A series of pyrazolo[1, 2-a]pyrazoliumolates of type 3, 4, and 5 was prepared. Compound 4(R³ = CH₃) shows liquid crystalline properties (C 158.5 N 162 I).     

Two New Borates Built by Different Types of {B9} Cluster Units

Two new belt-like borates Na₄[B₉O₁₄(OH)₃]·0.5H₂O(1) and Na₅[B₉O₁₄(OH)₄](2) have been synthesized under solvothermal conditions. Both compounds contain unprecedented B₉O₁₆(OH)_n^(n+5)-[n=3(1), 4(2)] clusters, which are constructed from four B₃O₃ rings via three BO₄ tetrahedra. Compound 1 exhibits a rare 1D belt with two types of 8-membered ring(MR) windows based on B₉O₁₆(OH)₃^8- clusters. Compound 2 features two different 1D belts built by different B₉O₁₆(OH)₄^9- units, which is first discovered in borate family. UV-Vis diffuse reflectance spectra reveal that compounds 1 and 2 have the cut-off edges below 190 nm, indicating that they may have potential application in deep UV(DUV) region.     

Evaluation of carborane-containing nematic liquid crystals for electro-optical applications

Three new structurally similar compounds in series 1[2] and 2 containing 12- and 10-vertex p-carborane units (A and B) were prepared. Their thermal properties were investigated in the pure state and compared to those of their carbocyclic analogues. Using several higher homologues in the series 1[n], clearing temperatures for the unknown 1[4] and 1[10] were predicted. Optical, dielectric and rotational viscosity parameters for carborane derivatives 1[2] and 2 and their cyclohexane analogies were obtained by extrapolation of values measured for 10% solutions in a standard nematic host. The observed trends were rationalised using computed molecular parameters.     

含磷稠杂环的合成及其生物活性(Ⅴ)

研究了氯代膦酰基异氰酸酯与5-氨基-3-苄硫基-1,2,4-三唑及其类似物的成环反应,合成了12个7-芳基(烷氧基)-2苄硫基-5,7-二氧代-4,5,6,7-四氢-7-磷杂-1,2,4-三唑[1,5a]三嗪,利用¹HNMR、³¹PNMR确定其Z型,生物活性测定结果表明,部分化合物具有一定的除草活性。     

A Novel Cyclization of Squalene Initiated by Radical Cation

Squalene 1 is recognized as the precursor of sterols and polycyclic triterpenoids that play important roles in numerous life processes¹. In view of the fact that the cyclization of hexa-1, 5-diene by γ-irradiation² and some isoprenoid polyenes by photochemical method³ through radical cation intermediates have been reported and that tris (p-bromophenyl)ammoniumyl hexachloroantimonate (TBPA⁺SbCl₆, 2) could oxidize olfines to the corresponding radical cations that underwent pericyclic reactions⁴, we thought it might be worthwhile to try the biomimetic cyclization of squalene initiated by radical cations. Previously we⁵ have reported the cyclization of geraniol and nerol to cis-p-mentha-2,8-dien-l-ol by reaction with 2. Herein, we report the cyclization of 1 initiated by 2 in dry dichloromethane to give 20-R-protosta-5,24-diene 3a and 20-S-protosta-5,24-diene 3b in the ratio of 1:1 with the total yield of 20%(Scheme 1).     

Synthesis and cytotoxicity of 28-carboxymethoxy lupane triterpenoids. Preference of 28-O-acylation over 28-O-alkylation of betulin by ethyl bromoacetate

28-Carboxymethoxy lupane tritepenoids 3 and 4 were synthesized by alkylation of betulin with the THP protected 2-hydroxyethyl iodide followed by oxidation and reduction.Direct reaction of betulin (5) or betulone (10) with ethyl bromoacetate led to 28-O-acylation, instead of 28-O-alkylation.The targeted compounds 3 and 4 were not cytotoxic at the highest concentrationtested (75 mmol/L), suggesting that elongation of the chain length at the 28-position in both betulinic acid (1) and betulonic acid (2)was detrimental to the cytotoxicity.The acylation products 28-O-bromoacetates (8a, 8b and 11) and 28-O-methoxyacetate 13exhibited cytotoxicity against several cancer cell lines tested.     

A Multifunctional {P2Mo5}-based Hybrid Applying to Catalysis,Electrocatalysis and Dye Adsorption

As a common environmental pollutant, thioether can cause serious environmental pollution, so selective oxidation of thioether has become one of the current research hotspots. In this paper, an inorganic-organic hybrid based on a Standberg-type polyoxometalate,[Hbiz]₅[HP₂Mo₅O₂₃]·5H₂O(1)(biz=benzimidazole), was obtained by adjusting pH under hydrothermal conditions. The structure was characterized by infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Compound 1 can be used as an excellent catalyst for the oxidation of thioanisole. The experimental results showed that thioanisole could be catalytically oxidized to methyl phenyl sulfoxide by compound 1 as a catalyst within 40 min. The conversion rate and selectivity reached 99%. Compound 1 had good cycling stability as a heterogeneous catalyst. In addition, the electrocatalytic reduction of H₂O₂ and Cr₂O₇^2‒ for hybrid 1 was preliminarily investigated. In addition, the adsorption performance of hybrid 1 on cationic dye crystal violet and methylene blue was tested, and the adsorption efficiencies can reach 98.5% and 86.3%, respectively.     

Study on'the α-Thiocarbonylthioformamide Ⅱ——Dehydrogenation of tetrahydronaphthalene

α-Thiocarbonylthioformamides were synthesized in 1980^[1-3]. Authors first explored their dehydrogenation reaction at high temperature. In our initial experiment, α-Thiobenzoylthioformmorpholine(l) was heated with diethyl acetylene dicarboxylate in tetrahydronaphthalene(2). The reaction is shown as following.     

Mesogenic aromatic esters with sulphur containing alkyl chains

A new series of aromatic esters, 1 and 2 with a sulphur atom in one of the side chains, is described. They exhibit nematic and/or smectic A/C mesophases as a function of the length of the alkyloxy chain. The presence of sulphur in the 4-position of the alkanoyloxy chain depresses both the clearing and the melting points with respect to the corresponding carbon analogues 3, resulting from the higher conformational mobility of the thiaalkyl chain. In 2, the presence of a methyl group in the 2-position of the alkanoyloxy chain induces a S_A phase below room temperature.     

AN EFFICIENT SYNTHESIS OF ALIPHATIC α-ORGANOTHIO ALDOXIME

The importance of the aliphatic α-organothio aldoxime compound 3 in the preparation of various pesticides is well established. Molecules comprising the α-organothio oxime moiety have been reported to exhibit insecticidal,nematocidal,miticidal activities.^[1-2] In the synthesis of the compound 3,the chlorination of the corresponding aliphatic aldoxime 1 is the key step.In conventional methods, the aliphatic aldoxime 1 is chlorinated by chlorine,then the resulting hydroxime acid chloride 2 is treated with sodium alkyl mercaptide to obtain the desired compounds 3^[3]. Although free Cl₂ is the most common chlorinating agent,it is laborious to determine the accurate amount that has been absorbed,and the high reactivity of Cl₂ always leads to side reactions. In connection with an our ongoing research project, we require an efficient and simple method for the synthesis of the compound 3.An improved synthesis process according to the following scheme is reported in this paper.     

Solvothermal Syntheses and Characterization of Three One-dimension Cadmium Selenidoarsenates [Ni(1,2-dap)3][As2CdSe4],[Zn(1,2-dap)3][As2CdSe4] and [Ni(en)3][As2CdSe4]

Three new cadmium selenidoarsenates,[Ni(1,2-dap)3][As2CdSe4](1)(1,2-dap=l,2-diaminopropane),[Zn( 1,2-dap)3][As2CdSe4](2) and [Ni(en)3][As2CdSe4](3)(en=ethylenediamine), were synthesized under solvothermal conditions. And they are isostnictural and monoclinic crystalls. As seen from their structures, they exhibited one-dimensional(1D) chains composed of [As2CdSe4]^2- anions and [TM(amine)3]^2+(TM=Ni,Zn;amine=1,2-dap, en) cations. Their absorption edges are 2.32, 1.84 and 2.38 eV and they show the properties of the semiconductor. These compounds were also characterized by means of single-crystal X-ray ditlraction(XRD), powder X-ray diflraction (PXRD), solid-state optical absorption spectrometry, and so on.     

Construction of a nano-rectangular Zn-Nd complex with near-infrared luminescent response towards metal ions

One 6-metal Zn-Nd complex[Zn₂Nd₄L₂(OAc)₁₀(OH)₂(CH₃OH)₂](1)with Schiff base ligand bis(3-methoxysalicylidene)ethylene-1,2-phenylenediamine(H₂L)was constructed,and it has nanoscale rectangular structure(8×11×28 A).Excited by ligand-centered absorption bands,1 shows NIRemission of Nd³⁺ion.Interestingly,1 exhibits lanthanide luminescent response towards metal ions,especially to alkali metal ions(Li⁺,Na⁺ and K⁺)at ppm level.     

Anionic Cyclization Approach to Hexahydrobenzo[b] furan-3-one and Hexahydro-1H-3-indolone:Application to Total Syntheses of Natural Products

Hexahydrobenzo[b]furan-3-one(3) and hexahydro-1H-3-indolone (4) are potentially useful intermediates for total synthesis of natural products, such as the hexahydrobenzofuran unit (5) of avermectins and pancracine (6). Anionic cyclization approach toward (3) and (4) have been developed. Their application to the total synthesis of (5) and (6) will be presented.