SO42-/Zr-ZSM-5 超强酸催化剂的制备和表征

以硅溶胶和氧氯化锆为硅源和锆源，采用水热合成的方法制得具有ZSM-5结构的Zr-Si分子筛；用0.5mol/L的硫酸处理该分子筛，并在550℃焙烧，制得具有ZSM-5结构的SO4^2-/ZrO2-SiO2分子筛型的固体超强酸。采用XRD、SEM、TG、IR、NH3-PHD和指示剂法对其结构和酸性进行表征。结果表明，该SO4^2-/ZrO2-SiO2具有ZSM-5结构和超强酸性，其酸强度大于-13.75，且具有良好的热稳定性。     

Synthesis of isomeric 3-phenyl-5-(pyridylmethylene)-2-thiohydantoins and their S-methylated derivatives. Molecular and crystal structures of (5Z)-3-phenyl-5-(pyridin-2-ylmethylene)-2-thiohydantoin and (5Z)-2-methylthio-3-phenyl-5-(pyridin-2-ylmethylene)-3,5-dihydro-4H-imidazol-4-one

Three procedures were used for the synthesis of -, , and -pyridyl-substituted (5Z)-3-phenyl-5-(pyridylmethylene)-2-thiohydantoins: the reaction of 2-thiohydantoin with the corresponding aldehyde in AcOH in the presence of AcONa, the two-step one-pot synthesis with the use of the same starting compounds, and three-component condensation of aryl isothiocyanate, glycine, and aldehyde in AcOH. Alkylation of the resulting thiohydantoins with iodomethane in the presence of a base afforded the corresponding S-methylated derivatives, viz., 2-methylthio-3-phenyl-5-(pyridylmethylene)-3,5-dihydro-4H-imidazol-4-ones. The structures of (5Z)-3-phenyl-5-(pyridin-2-ylmethylene)-2-thioxoimidazolin-4-one and (5Z)-2-methylthio-3-phenyl-5-(pyridin-2-ylmethylene)-3,5-dihydro-4H-imidazol-4-one were established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2734–2739, December, 2004.     

Spectrophotometric determination of cadmium(II) using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

The complex of cadmium with the reagent 2-(-5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) has been studied. The composition, stability constant, and free energy change of formation of the complex have been determined. A sensitive spectrophotometric method for the determination of cadmium has been developed and applied for a range of concentration of 0.4–4.0 μg/ml cadmium using the complex Cd-5-Br-PADAP. The optimum conditions for maximum sensitivity of determination such as standing time, pH, wavelength, and order of addition have been determined. The effect of foreign ions on this method has been also studied.     

Structural and spectral studies of N-2-(pyridyl)-, N-2-(3-, 4-, 5-, and 6-picolyl)- and N-2-(4,6-lutidyl)-N′-2-thiomethoxyphenylthioureas

Structures of the following compounds have been obtained: N-(2-pyridyl)-N′-2-thiomethoxyphenylthiourea, PyTu2SMe, monoclinic, P2₁/c, a=11.905(3), b=4.7660(8), c=23,532(6) Å, β=95.993(8)°, V=1327.9(5) ų and Z=4; N-2-(3-picolyl)-N′-2-thiomethoxyphenyl-thiourea, 3PicTu2SeMe, monoclinic, C2/c, a=22.870(5), b=7.564(1), c=16.941(4) Å, β=98.300(6)°, V=2899.9(9) ų and Z=8; N-2-(4-picolyl)-N′-2-thiomethoxyphenylthiourea, 4PicTu2SMe, monoclinic P2₁/a, a=9.44(5), b=18.18(7), c=8.376(12) Å, β=91.62(5)°, V=1437(1) ų and Z=4; N-2-(5-picolyl)-N′-2-thiomethoxyphenylthiourea, 5PicTu2SMe, monoclinic, C2/c, a=21.807(2), b=7.5940(9), c=17.500(2) Å, β=93.267(6)°, V=2893.3(5) ų and Z=8; N-2-(6-picolyl)-N′-2-thiomethoxyphenylthiourea, 6PicTu2SMe, monoclinic, P2₁/c, a=8.499(4), b=7.819(2), c=22.291(8) Å, β=90.73(3)°, V=1481.2(9) ų and Z=4 and N-2-(4,6-lutidyl)-N′-2-thiomethoxyphenyl-thiourea, 4,6LutTu2SMe, monoclinic, P2₁/c, a=11.621(1), b=9.324(1), c=14.604(1) Å, β=96.378(4)°, V=1572.4(2) ų and Z=4. Comparisons with other N-2-pyridyl-N′-arylthioureas having substituents in the 2-position of the aryl ring are included.     

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

<正>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.     

Regioselective synthesis of cytotoxic 4-(1-alkynyl)-substituted 2-(5H)-furanones

4-(1-Alkynyl)-3-bromo- and 4-(1-alkynyl)-3-chloro-2(5H)-furanones have been regioselectively synthesized in moderate to good yields by a new version of the Pd/Cu-catalyzed Sonogashira reaction involving treatment of 1-alkynes with 3,4-dibromo- and 3,4-dichloro-2(5H)-furanone, respectively, in the presence of KF as a base. 4-(1-Alkynyl)-3-bromo-2(5H)-furanones have been found to be able to undergo Stille-type and Suzuki-type reactions with aryl(tributyl)tins and arylboronic acids, respectively, to give 4-(1-alkynyl)-3-aryl-2(5H)-furanones in modest to satisfactory yields. Some 4-(1-alkynyl)-substituted 2(5H)-furanones so prepared have been found to exhibit significant cytotoxic activities, especially against human leukemia cell lines.     

Regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles

[reaction: see text] Highly efficient and regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles has been reported via cyclocondensation of arylhydrazines with either alpha-oxoketene dithioacetals or beta-oxodithioesters.     

Novel routes to chiral 2-alkoxy-5-/6- methoxycarbonylmethylidenepyrrolidines/-piperidines

We report the results of a study aimed at the diastereoselective synthesis of chiral 2-alkoxy-5-/6-methoxycarbonylmethylidenepyrrolidines/-piperidines by condensation of chiral amines onto omega-oxo alkynoates and omega-oxo beta-keto esters.     

Synthesis and Some Chemical Conversions of 2-([2,2]-5-Paracyclophanyl)pyrrole

2-([2,2]-5-Paracyclophanyl)pyrrole has been synthesized and nitration and formylation of it have been effected. The 1--cyanoethyl derivative and 2-formyl-5-paracyclophanyl-3H-pyrrolizine have been obtained from 5-formyl-2-([2,2]-5-paracyclophanyl)pyrrole by the action of acrylonitrile and acrolein respectively under Michael reaction conditions.     

Synthesis and Crystal Structure of （4S）-5-（2-Methoxy-2-oxoethylamino）-5-oxo-4-（3,4,5-trimethoxybenzamido） Pentanoic Acid

1 INTRODUCTION Aminopeptidase N (APN), a member of mem- brane-bound zinc-dependent exopeptidase, is known to be high expression on the brush border membran- es of the small intestine and renal proximal tubules[1]. The over-expression of APN has been involved in several pathological conditions including cancer[2], leukemia, diabetic nephropathy[3], rheumatoid arth- ritis[4], angiogenesis[5] and central nervous system di- seases, such as Alzheimer’s disease[6]. This has led to the sear…     

Regioselective rapid analog synthesis of 1,3-(or 1,5-)diphenyl-4-aryl/heteroaryl-5-(or 3-)(methylthio)pyrazoles via Suzuki cross-coupling

Regioselective routes for the synthesis of 1,3-(or 1,5-)diphenyl-4-aryl/heteroaryl-5-(or 3-)(methylthio)pyrazoles via Suzuki cross-coupling of 4-bromo (or 4-iodo)-1,3-(or 1,5-)diphenyl-5-(or 3-)(methylthio)pyrazoles have been reported.     

Synthesis of (5R)- and (5S)-5-Methyl-5, 6-dihydrouridine Derivatives

The hydrogenation of 2′, 3′-O-isopropylidene-5-methyluridine (1) in water over 5% Rh/Al₂O₃ gave (5 R)- and (5 S)-5-methyl-5, 6-dihydrouridine (2) , separated as 5′-O-(p-tolylsulfonyl)- (3) and 5′-O-benzoyl- (5) derivatives by preparative TLC. on silica gel and ether/hexane developments. The diastereoisomeric differentiation at the C(5) chiral centre depends upon the reaction media and the nature of the protecting group attached to the ribosyl moiety. The synthesis of iodo derivatives (5 R)- and (5 S)- 4 is also described. The diastereoisomers 4 were converted into (5 R)- and (5 S)-2′, 3′,-O-isopropylidene-5-methyl-2, 5′-anhydro-5, 6-dihydrouridine (7) .     

2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噁二唑/噻二唑类化合物的合成及生物活性

以5-氨基-1H-1,2,4-三唑-3-羧酸乙酯为起始原料, 设计合成了11个新型的2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噁二唑类化合物(5)和6个新型的2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噻二唑类化合物(8). 通过¹H NMR, MS和元素分析对所合成的化合物进行了结构表征. 初步的生物活性测试结果表明, 所合成的化合物均表现出不同程度的除草及杀菌活性, 其中化合物5k和8f的活性最好, 在50 mg/L浓度下对水稻纹枯病菌的抑制率达90%以上.     

Studies on Reactions of 2-Amino-5-Heterocyclyl-1,3,4- -Thia/Oxadiazole with Acylisothiocyanates

It is well known that the addition of acyl isothiocyanate with amine formed 1,3-disubstituted thiourea which possess broad spectrum biological activities, Up till now, the addition of 5-heterocyclyl-2-amino-1,3,4-thia/oxadiazole with acylisothicyanate has not been reported. We wish to describe this reaction in this paper. When the new 2-amino-5-(l-p-chlorophenyl-5-methyl-1,2,3-triazol-4-yl)-1,3,4-thiadiazole (Ⅰ) was reacted with acylisothio-cyanates (Ⅱ), not all the compounds were expected acylthiourea (Ⅲ)^[1,2], some of them were acid amide (Ⅳ). The formation of the products was determined by the substituents of the acylisothiocyanate. In order to investigate the reaction, we synthesized 2-amino-5-aryl-1,3,4-thio/oxadiazole (Ⅴa,b), and then reacted with 1-p-chlorophenyl-5-methyl-1,2,3-triazol-4-formyl-isothiocyanate (Ⅵ). As it was anticipated, the products only were N-(5-aryl-1,3,4-thia/oxadiazol-2-yl)-N'-(1-p-chlorophenyl-5-methyl-1,2,3-triazol-4-formyl) thiourea (Ⅶa,b) (Scheme).     

Syntheses of 3-[5-Methyl-1-(4-Methylphenyl)-1,2,3-Triazol-4-yl]-6-Substituted-s-Triazolo[3,4-b]-1,3,4-Thiadiazoles

1,2,3-Triazole derivatives have been reported as inhibiting tumor proliferation, invasion, and metastasis^[1]. The fused l,3,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives show various biological effects such as antifungal^[2], antibacterial, hypotensive and CNS depressant activities^[3]. We have reported several 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazoles in the previous paper^[4]. The novel 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[2,4-b]-1,3,4-thiadiazoles 6a-j have been synthesized by the condensation of 4-amino-5-mercapto-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazole 5 with various aromatic carboxylic acids in the presence of phosphorus oxychloride. The mercaptotriazole 5 was prepared from 4,the latter being prepared from 1 throng 2 and 3. The title compounds 6 were depicted in scheme 1. The structures of these compounds were established by elemental analysis, NMR, MS and IR techniques.     

Enthalpies of formation of gas-phase N3, N3-, N5+, and N5- from Ab initio molecular orbital theory, stability predictions for N5(+)N3(-) and N5(+)N5(-), and experimental evidence for the instability of N5(+)N3(-)

Ab initio molecular orbital theory has been used to calculate accurate enthalpies of formation and adiabatic electron affinities or ionization potentials for N3, N3-, N5+, and N5- from total atomization energies. The calculated heats of formation of the gas-phase molecules/ions at 0 K are DeltaHf(N3(2Pi)) = 109.2, DeltaHf(N3-(1sigma+)) = 47.4, DeltaHf(N5-(1A1')) = 62.3, and DeltaHf(N5+(1A1)) = 353.3 kcal/mol with an estimated error bar of +/-1 kcal/mol. For comparison purposes, the error in the calculated bond energy for N2 is 0.72 kcal/mol. Born-Haber cycle calculations, using estimated lattice energies and the adiabatic ionization potentials of the anions and electron affinities of the cations, enable reliable stability predictions for the hypothetical N5(+)N3(-) and N5(+)N5(-) salts. The calculations show that neither salt can be stabilized and that both should decompose spontaneously into N3 radicals and N2. This conclusion was experimentally confirmed for the N5(+)N3(-) salt by low-temperature metathetical reactions between N5SbF6 and alkali metal azides in different solvents, resulting in violent reactions with spontaneous nitrogen evolution. It is emphasized that one needs to use adiabatic ionization potentials and electron affinities instead of vertical potentials and affinities for salt stability predictions when the formed radicals are not vibrationally stable. This is the case for the N5 radicals where the energy difference between vertical and adiabatic potentials amounts to about 100 kcal/mol per N5.     

Synthesis and Crystal Structure of Diethyl 5-Acetoxy-3-（4-chlorophenyl）- 4,5-dihydroisoxazol-5-yl-5-phosphonate

1INTRODUCTION Isoxazole derivatives are an important class of heterocycles as intermediates for natural product synthesis and building blocks for constructing new molecular systems[1,2].In addition,isoxazole deriva-tives have been long targeted in synthetic inves-tigation for their known biological activities and pharmacological properties such as hypoglycemic,analgesic,anti-inflammatory and anti-bacterial acti-vities[3~6].Therefore,the isoxazolines and isoxazoles with phosphonate group ar…     

2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯胺与铑显色反应的研究及应用

本文报道了以新试剂2-(5-硝基-2吡啶偶氮)-5-二甲氨基苯胺(5-NO_2-PADMA)作分光光度法测定铑的新体系.结果表明,在 PH=5.25～6.75范围内,铑与 5-NO_2-PADMA形成 1:1的紫红色络合物,其 λ_(max)在 525 nm处,该络合物在 1.8mol/L的盐酸溶液中转变为绿兰色,其最大吸收峰位于620nm处,表观摩尔吸光系数为1.39×10～5L·mol～1·cm～1.反应具有良好的选择性,常见金属离子在一定范围内无干扰.铑含量为0～0.56μg/mL范围内遵守比耳定律.所拟方法操作简便,灵敏度高,用于催化剂中微量铑的测定,结果满意.     

1,3-二(乙氧基甲基)-5-N,N-二甲氨基-6-甲基尿嘧啶的合成

报道了1,3-二(乙氧基甲基)-5-N,N-二甲氨基-6-甲基尿嘧啶方便、高产率的合成方法. 以6-甲基尿嘧啶(1)为起始物, 经硝化、嘧啶N¹,N ³-烷基化、还原及氨基甲基化, 首次高产率合成了1,3-二(乙氧基甲基)-5- N,N -二甲氨基-6-甲基尿嘧啶(5), 并对其化学结构进行了表征.     

2－氯／2－甲磺酰基－5－（2－苯基－4－喹啉基）－1，3，4－噁二唑化合物的合成及其亲核取代的研究

借处理２－羟基－５－（２－苯基－４－喹啉基）－１，３，二唑同ＰＣｌ＿５／ＰＯＣｌ＿３之间的反应合成了２－氯－５－（２－苯基－４－喹啉基）－１，３，４－二唑（３）和通过２－基－５－（２－苯基－４－喹啉基）－１，３，４－二唑的甲基化，然后氧化制得２－甲磺酰基－５－（２－苯基－４－喹啉基）－１，３，４－二唑（６）．并分别研究了３和６同胺、叠氮及肼的反应，得到２，５－二取代的二唑新衍生物．初步观察了部分化合物的抗菌活性．