Heteropoly Complexes Na0.5Cs2 ? x[H0.5 ? xM

Crystals of novel heterepoly complexes (HPC) Na_0.5Cs_{2 − x} [H_{0.5 − x} M _x ^II X^III(OH)₆Mo₆O₁₈] · 7−8H₂O (M^II = Fe, Mn; X^III = Cr, Al) are synthesized. Crystal structures of the complexes Na_0.5Cs_{2 − x} [H_{0.5 − x} Fe_xCr(OH)₆Mo₆O₁₈] · 7H₂O (I) (x = 0.19) and Na_0.5Cs_{2 − x} [H_{0.5 − x} Mn_xAl(OH)₆Mo₆O₁₈] · 8H₂O (II) (x = 0.22) are determined (space group Pbcn, Z = 8, a = 23.023(4) Å, b = 22.064(4) Å, c = 11.606(3) Å, V = 5895.66 ų for I and a = 22.972(9) Å, b = 22.002(8) Å, c = 11.543(5) Å, V = 5834.18 ų for II, respectively). The [X^III(OH)₆Mo₆O₁₈]³⁻ ligands were found to be coordinated in monodentate fashion to M atoms due to the participation of a terminal O atom of the cis-MoO₂ group in coordination with the Fe and Mn atoms, which was confirmed by IR data. __________ Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 9, 2005, pp. 663–676. Original Russian Text Copyright ? 2005 by Gavrilova, Molchanov.     

Synthesis and Conformational Studies of Unnatural Pyrimidine Nucleosides

ABSTRACT

Starting from 3,4-di-O-acetyl-L-rhamnal (6) and thymine (7) the unsaturated nucleosides 1-(2′,3′,6′-trideoxy-4′-O-acetyl-α- and β-L-erythro-hex-2′-enopyranosyl)-thymine (8a and 8b) were prepared in anomerically pure form. In solution 8a was shown to be present in the ⁵ H _o and ⁰ H ₅ conformations, whereas the predominant conformation of 8b was ⁵ H _o. Chemical transformation of 8a and 8b led to the saturated nucleosides 1-(2′,3′,6′-trideoxy-α- and β-L-erythro-hexopyranosyl)thymine (10a and 10b, respectively), which were converted into 1-(4′-azido-2′,3′,4′,6′-tetradeoxy-α- and β-L-threo-hexopyranosyl)thymine (12a and 12b). Preliminary biological studies showed that 9b was inactive against the HIV-1 and HIV-2 viruses.     

胍基木吡喃糖苷的合成及其抗HIV蛋白酶活性

2,3,4-三-O-乙酰基-b-D-木吡喃糖基异硫氰酸酯1与2-氨基-4/6-取代-苯并噻唑2a～2e反应, 生成糖基硫脲衍生物3a～3e, 再在伯胺存在下经氯化汞脱硫, 得到一系列新的胍基木吡喃糖苷类化合物4a～4e, 5a～5e, 6a～6e, 7a～7e, 所有新化合物的结构均经IR, ¹H NMR, MS谱和元素分析证实, 所得产物均为β-构型. 生物活性测试结果表明, 化合物4c, 5b, 6b～6d, 7b等对HIV-1蛋白酶表现出了较高的抑制活性.     

Synthesis of 2,6-Dideoxy-6-Thio Derivatives of KDO

ABSTRACT

Ammonium 2,3,6-trideoxy-2,6-epithio-D-manno-2-octenoate (8), ammonium 2,3,6-trideoxy-2,6-epithio-D-glycero-D-talo-octanoate (10a), ammonium 2,3,6-trideoxy-2,6-epithio-D-glycero-D-galacto-octanoate (10b) and ammonium 2,3,6-trideoxy-2,6-epithio-oxa-D-glycero-D-galacto-octanoate (13) have been synthesised as potential inhibitors of the enzyme CMP-KDO synthetase. The key step in the synthesis of 8 was the elimination of water from methyl 3,6-dideoxy-4,5:7,8-di-O-isopropylidene-6-thio-D-manno-2-octulosonate (4) using chlorodiphenylphosphine, imidazole and bromine to give the unsaturated methyl 2,3,6-trideoxy-2,6-epithio-4,5:7,8-di-O-isopropylidene-D-manno-2-octenoate (5). For the synthesis of 10a and 10b, zinc reduction of methyl 3,6-dideoxy-4,5:7,8-di-O-isopropylidene-6-S-(4-methoxybenzyl)-6-thio-2-O-(trichloro-tert-butoxycarbonyl)-D-manno-2-octenoate (2) gave an epimeric mixture of an α-hydroxyester 6 which was ring closed by in situ activation of the hydroxyl group using triphenylphosphine and tri-iodoimidazole followed by cleavage of the p-methoxybenzyl group to give 7a and 7b, which then were deprotected to give 10a and 10b.     

SYNTHESES,STRUCTURES AND REACTIONS OF NEW AND NOVEL FOUR-, FIVEAND SIX-MEMBERED UNSATURATED N,P-HETEROCYCLE COMPLEXES

Metal-assisted heterocyclic ligand syntheses are reported using 2-H-azaphosphirene complex 1 or 7-phosphanorbornadiene complex 7 as starting material. Thermal decomposition of complex 1 led to 1,2dihydro-1,2,3-azadiphosphete complex 2, which was transformed into 2,6-dihydro-1,3,2,6-diazadiphosphinines 5a, b via ring expansion with carbonitriles 3a, b. Insertion of tert-butyl isonitrile into the P─ P bond of 2 at ambient temperature furnished the first Δ ¹ -1,3,5-azadi-phospholene complex 6─P bond of 2 using 7 failed. The 1,2,3,4-azatriphospholene complexes 9a, b were obtained by thermolysis of complex 2 in the presence of functionalized carbonitriles 8a, b.     

Synthesis,Recognition of Metal Ions of Salicylidenimine Functionalized p-tert-Butylcalix[n]arene-core Dendrimers

A series of salicylidenimine functionalized p-tert-butylcalix[n]arene-core dendrimers 7a–b were synthesized in higher yields by divergent method from the corresponding ethyl p-butylcalix[n]arylacetates 2a–b (n = 6, 8). 2a–b were first treated with excess of 1,6-diaminohexane to give amide derivatives with free amine terminal groups 3a–b, which in turn reacted with salicylaldehyde in alcohol to yield the first generation of Schiff bases 4a–b. 3a–b reacted with ethyl acrylate, ammonolized with 1,6-diaminohexane and condonsated with salicylaldehyde successfully to give the second generation of Schiff bases 7a–b. The extraction and binding properties of the dentritic Schiff bases 4a–b and 7a–b for several kinds of metal ions were studied with UV–Vis spectroscopy and atomic absorption spectroscopy. In which they showed a great affinity for soft Cu^2 +  ions and formed 1:1 or 1:2 stoichiometric complexes.     

Synthesis,characterization, DNA binding studies and in vitro cytotoxicity of platinum(II)-dihalogenido complexes containing bidentate chelating N-donor ligands

Platinum(II) complexes, [Pt(L_x)X₂] (1–6), where X = Br or I and L_x = 2,2′-bipyridine or 1,10-phenanthroline derivatives (5,5′-dimethyl-2,2′-bipyridine (5-Mebpy), 4,4′-dimethyl-2,2′-bipyridine (4-Mebpy), and 5-amino-1,10-phenanthroline (5-NH₂phen)) were prepared. The complexes were characterized by the elemental analysis, mass spectrometry, infrared, and multinuclear (¹H, ¹³C and ¹⁹⁵Pt) 1-D and 2-D NMR spectroscopies, and by single-crystal X-ray analysis of [Pt(4-Mebpy)I₂] (4). All the platinum(II) complexes (1–6) were evaluated for in vitro cytotoxicity against human cancer cell lines A2780 and A2780R, and against non-malignant MRC5 cell line. All the complexes were nontoxic up to the 50 μM concentration, although they were found to readily bind to calf-thymus DNA (CT-DNA), as determined by spectrophotometric titration (K_b ≈ 10⁷ M^?1) and ethidium bromide displacement assay.     

3-Methyl[1,3,4]thiadiazino[2,3-b]quinazolin-6-ones

4H,6H-[1,3,4]Thiadiazino[2,3-b]quinazolin-6-one with a methyl group in position 3 (6a) has been synthesised by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (1) with allyl bromide (2) followed by treatment with bromine and subsequent dehydrohalogenation of the brominated product (4) with ethanolic sodium hydroxide. Its isomeric 3-methyl-2H,6H-[1,3,4]thiadiazino[2,3-b]quinazolin-6-one (6b) has also been obtained by condensation of1 and bromoacetone (7) followed by cyclisation of the intermediates (8 or9) with hydrobromic acid or with concentrated sulphuric acid. The structures have been established on the basis of IR and PMR data.

---

3-Methyl[1,3,4]thiadiazino[2,3-b]chinazolin-6-one

Zusammenfassung Zur Synthese von 4H,6H-[1,3,4]thiadiazino[2,3-b]chinazolin-6-on (6a) wurde die Kondensation von 3-Amino-2-mercapto-3H-chinazolin-4-on (1) mit Allylbromid mit nachfolgender Behandlung mit Brom und Dehydrohalogenierung des bromierten Produktes4 mit ethanolischer Natronlauge herangezogen. Das zu6a isomere 2H,6H-Produkt6b wurde ebenfalls durch Kondensation von1 mit Bromaceton und nachfolgender Cyclisierung der Zwischenprodukte8 bzw.9 mit HBr oder H₂SO₄ erhalten. Die Strukturen wurden mittels IR und NMR abgesichert.

     

Traceable platinum(II) complexes with alkylene diamine-derived ligands: synthesis,characterization and in vitro studies

Diiodido- (6a/6b) and dichloridoplatinum(II) complexes (7a/7b) with fluorescent ligands 2-[(2-aminoethyl)amino]ethyl-2-(methylamino)benzoate (5a) and 2-amino-1-(aminoethyl)ethyl-2-(methylamino)benzoate (5b) were prepared and characterized by elemental analysis, ESI-MS analysis, fluorescence spectrometry, as well as ¹H, ¹³C, and ¹⁹⁵Pt NMR spectroscopy. All compounds have been tested against A2780 ovarian cancer, A549 lung carcinoma, and HT-29 colon cancer cell lines using sulforhodamine-B assay. The activity increased from ligand precursors, diiodido- to dichloridoplatinum(II) complexes, except against HT-29 cell line where diiodido and dichlorido expressed similar activity. These compounds enter the tumor cells and emit a bright fluorescence at ca. 470 nm, mainly targeting nuclei.     

Synthesis and Cation-Binding Properties of (1→6)-2,5-Anhydro-D-glucitol with 3,4-Di-O-Pentyl and Decyl Groups by Cyclopolymerization of 1,2:5,6-Dianhydro-D-mannitols

Abstract

The cyclopolymerizations of 1,2:5,6-dianhydro-3,4-di-O-pentyl-D-mannitol (1b) and 1,2:5,6-dianhydro-3,4-di-O-decyl-D-mannitol (1c) were carried out using BF₃OEt₂ and t-BuOK. All the resulting polymers consisted of cyclic constitutional units, i.e., the extent of cyclization was 100%. The polymer structures for the polymerization with t-BuOK were (1→6)-2,5-anhydro-3,4-di-O-pentyl-D-glucitol (2b) and (1→6)-2,5-anhydro-3,4-di-O-decyl-D-glucitol (2c), whereas those with BF₃O-decyl₂ comprised 2,5-anhydro-D-glucitols as major units along with other cyclic ones. These polymers were soluble in n-hexane, CHCl₃, and THF, but insoluble in water, which differs from the amphiphilic solubility of (1→6)-2,5-anhydro-3,4-di-O-methyl-D-glucitol (2a). The cation-binding properties of 2b and 2c were examined using alkali-metal picrates in order to compare them with those of 2a. The extraction yields for each cation decreased in the order of 2c < 2b < 2a. Every polymer exhibited a similar cation-binding selectivity in the order Cs⁺ > Rb⁺ > K⁺ ? Na⁺ > Li⁺. The ratio of K⁺ and Na⁺, K⁺/Na⁺, was 4.6 for 2a, 5.1 for 2b, and 7.1 for 2c in the increasing order 2a < 2b > 2c.     

The Synthesis of Triazolothiadiazines and Thiadiazoles From 1,2-Bis-(4-amino-5-mercapto-1,2,4-triazol-3-yl)- Ethanol and Ethane

The reaction of DL-malic and succinic acids with thiocarbohydrazide afforded 1,2-bis[4-amino-5-mercapto-1,2,4-triazol-3-yl]-ethane derivatives 3a and 3b. The reaction of 3a,b with phenacyl bromide and benzoin afforded 1,2-bis-1,2,4-triazolo [3,4-b][1,3,4]thiadiazine derivatives 4 and 5. The carboethoxymethylation of 3a and 3b gave 6a and 6b, respectively, and their reactions with carbon disulfide and benzoylisothiocyanate gave the 1,2-bis-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole 7 and 9, and with p-nitrobenzaldehyde gave a Schiff's base and dihydrothiadiazole 8. The structures were confirmed by using ¹ H and ¹³ C NMR spectra. Selected members of these compounds were screened for antimicrobial activity.     

Efficient synthesis of some novel furo[3,2-e]pyrazolo[3,4-b]pyrazines and related heterocycles

A series of novel 6-functionalized-5-amino-3-methyl-1-phenyl-1H-furo[3,2-e]pyrazolo[3,4-b]pyrazines (4a–c) was synthesized by the reaction of 3-methyl-6-oxo-1-phenyl-6,7-dihydro-1H-pyrazolo[3,4-b]pyrazine-5-carbonitrile (2) with α-halocarbonyl compounds such as: diethyl 2-bromomalonate, phenacyl bromide and chloroacetone. Cyclocondensation of the amino benzoyl 4b with diethyl malonate yielded the oxopyridine carboxylate derivative 5. Also, the starting intermediate amino ester compound 4a was allowed to react with ethanol amine to afford the hydroxyethyl caboxamide derivative 6. Furthermore, hydrazinolysis of the amino ester 4a afforded the corresponding amino carbohydrazide 7 which was used as a versatile precursor for synthesis of other heterocyclic compounds attached or fused to the furopyrazolopyrazine moiety. The chemical structures of the newly synthesized compounds were confirmed on the basis of elemental and spectral analyses containing FT-IR, ¹H NMR, ¹³C NMR, and mass spectrometry hoping these molecules should allow us to investigate their pharmacological activities in the future study.     

Über die Darstellung der 7R-Oxirane von 5Z- und 5E-10-Oxo-19-norcholecalciferol

Summary The two title compounds12b and13b have been prepared by direct oxidation of the corresponding 10-oxo-19-norcolcalciferol derivatives3c and4c withMCPBA. The generation of12b and13b by treatment of the ⁷ epoxidized ethylisoxazolin adducts of 5Z- and 5E-cholecalciferol8a,8b and9a,9b with Mo(CO)₆ failed, since besides the retroaldol cleavage of the heterocycle a deoxygenation of the oxirane with retention of configuration to the ⁷ double bond occurs.

     

Stereoselective synthesis of trans-3-functionalized-4-pyrazolo[5,1-b]thiazole-3-carboxylate substituted β-lactams: Potential synthons for diverse biologically active agents

Abstract

An efficient protocol for the stereoselective synthesis of pyrazolo[5,1-b]thiazole-3-carboxylate tethered β-lactam conjugates 8a–j from novel pyrazolo [5,1-b]thiazole-3-carboxylate substituted Schiff’s bases 6a–f is reported here. The reaction between various ketene precursors and novel Schiff’s bases 6a–f afforded exclusive formation of trans-β-lactams 8a–j. The substrate scope of this approach was investigated extensively by varying different groups (R, Z). All the novel compounds were characterized using various spectroscopic techniques, such as FT-IR, ¹H NMR, ¹³C NMR, elemental analysis, ¹³C NMR (DEPT-135), and mass spectrometry in representative cases. Single crystal X-ray crystallographic study of trans-ethyl 7-(1-(4-methoxyphenyl)-4-oxo-3-phenoxyazetidin-2-yl)-6-methyl-2-(methylthio)pyrazolo[5,1-b]thiazole-3-carboxylate 8a has confirmed the molecular structure and the stereochemical outcome. To the best of our knowledge, the synthesis of such types of Schiff’s bases and β-lactam conjugates has not been reported so far.     

Icosandrin,a novel peltogynoid from the fruits of Phytolacca icosandra (Phytolaccaceae)

Besides the known compounds ( ± ) 3,3-bis-demethylpinoresinol (2), americanol A (3), spergulagenic acid (4), epi-acetylaleuritolic acid (5), 6′-palmityl-α-spinateryl-d-glucoside (6a) and 6′-palmityl-δ⁷-stigmastenyl-d-glucoside (6b), a novel peltogynoid (1) named icosandrin was obtained from the dried fruits of Phytolacca icosandra. This new compound was characterised by 1D-/2D-NMR, UV, IR and HR-MS techniques as 11ξ-methoxy-6,7-methylenedioxy-[2]benzopyrano-[4,3-b][1]-benzopyran-4-one. Toxicity of 1 was assessed through the Brine Shrimp Lethality Assay. Lignan 2 is reported for the first time in Phytolaccaceae family.     

A new type of pseudorotaxanes based on cucurbit[6]uril and bis-cyanopyridyl alkane compounds

Using bis-cyanopyridyl alkane compounds as guests, three cucurbit[6]uril-based new pseudorotaxanes (2a, 2b and 2c) were synthesised and characterised. The crystal structures for 2a and 2c have been determined and discussed. In addition, formation constants and thermodynamic parameters in aqueous solution, as well as thermal decomposition behaviour in solid state, have been studied by ¹H NMR and TGA techniques, respectively.     

Structure and properties of double complex salts [Co(NH3)6][Fe(CN)6] and [Co(NH3)6]2[Cu(C2O4)2]3

Double complex salts (DCSs) [Co(NH₃)₆][Fe(CN)₆] (I) and [Co(NH₃)₆]₂[Cu(C₂O₄)₂]₃ (II) and complex [Co(NH₃)₆]₂(C₂O₄)₃·4H₂O (III) are synthesized and investigated by single crystal XRD, crystal optics, and elemental analysis. The crystalline phases of I, II, and III (R-3, P2₁/c, and Pnnm space groups respectively) have the following crystallographic characteristics: a = 10.9804(2) ?, b = 10.9804(2) ?, c = 10.8224(3) ?, V = 1130.03(4) ?³, Z = 3, d _x = 1.65 g/cm³ (I); a = 9.6370(2) ?, b = 10.2452(2) ?, c = 13.2108(3) ?, V = 1932.90(9) ?³, Z = 2, d _x= 1.97 g/cm³ (II), and a = 11.7658(3) ?, b = 11.7254(3) ?, c = 14.1913(4) ?, V = 1304.34(5) ?³, Z = 2, d _x = 1.68 g/cm³ (III). This paper investigates the products of DCS thermolysis in a hydrogen atmosphere: the intermetallic compound CoFe with the bcc parameter a = 2.852 ? for I and a heterogeneous mixture of Co and Cu in the decomposition of II. The coordinated CN⁻ and C₂O₄²⁻ groups then turn into NH₃, hydrocarbons, and CO₂. The dominant hydrocarbon is methane.     

Synthesis of elastomeric polypropylene in bulk using C 1-symmetric ansa-metallocenes. New aspects of the synthesis of 1-(fluoren-9-yl)-2-(2-methyl-5,6-dihydrocyclopenta [f]-1H-inden-1-yl)ethane and complexes of zirconium and hafnium with this ligand

Isomeric 1-(fluoren-9-yl)-2-(2-methyl-5, 6-dihydrocyclopenta [f]-1 H-indenyl) ethanes 1a,b and C ₁-symmetric metallocenes, viz., rac-1-(η⁵-fluoren-9-yl)-2-(2-methyl-5, 6-dihydrocyclopenta [f]-η⁵-inden-1-yl) ethanezirconium dichloride (9) and rac-1-(η⁵-fluoren-9-yl)- 2-(2-methyl-5, 6-dihydrocyclopenta [f]η⁵-inden-1-yl)ethanehafnium dichloride (10), with these ligands were synthesized by modified procedures. The structures of compounds 1b (two crystalline modifications) and 10 were established by X-ray diffraction analysis. The synthesis of polypropylene (PP) in bulk was studied in the presence of polymethylalumoxane-activated metallocenes 9 and 10 in the temperature range of 30–70°C. It was demonstrated that triisobutylaluminum can be used as a cocatalyst. In this case, the molecular weight of PP increases by a factor of ∼2. An increase in the reaction temperature leads to an increase in stereoregularity and crystallinity of PP. The polymer synthesized at high temperatures crystallizes in the γ form. The resulting PP is characterized by a wide range of properties from rigid crystalline thermoplastic to amorphous elastomeric. Samples, which have a high molecular weight and moderate isotacticity, exhibit high elastomeric and durability properties.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 400–413, February, 2005.     

新型四酰胺杯[4]氮杂冠醚的合成及对阴离子的光化学传感性质研究

合成了一类新型四酰胺杯[4]氮杂冠醚(5a, 5b), 用紫外和荧光光谱研究了主体与阴离子客体之间的识别性能. 主体分子5a或5b加入到对硝基酚氧阴离子的CHCl₃溶液中, 主客体间形成超分子复合物使得客体阴离子423 nm处吸光度降低且溶液从黄色变为无色. 受体5a, 5b与p-NO₂C₆H₄O^－, F^－, 相互作用, 荧光光谱发生变化, 并且对于p-NO₂C₆H₄O^－具有较好的选择性识别能力, 其荧光光谱强度改变强弱的顺序为p-NO₂C₆H₄O^－＞F^－＞H₂PO₄^－>>Cl^－, Br^－, I^－. 荧光光谱滴定的结果经非线性拟合, 结果表明主客体间形成1∶1络合物.     

Synthesis,structure and isomerism of “three-bridge” exo-nido-osmacarborane clusters

The reaction of OsCl₂(PPh₃)₃ with [nido-7-R¹-8-R²-C₂B₉H₁₀]K⁺ produced a series of new exo-nido-osmacarborane complexes exo-nido-5,6,10-[Cl(Ph₃P)₂Os]-5,6,10-(-H)₃-10-H-7-R¹-8-R²-7,8-C₂B₉H₆ (1: R¹ = R² = H; 2: R¹ = R² = Me; 3: R¹ = R² = PhCH₂; 4: R¹ + R² = 1,2-C₆H₄(CH₂)₂; 5: R¹ = H, R² = Me) in which the osmium-containing group is linked to the nido-carborane ligand through three two-electron three-center bonds. Compounds 1—5 are formed as mixtures of symmetric (a) and asymmetric (b) isomers; pure symmetric isomers 2a and 4a were isolated by fractional crystallization, and the mixture of isomers 3a, was quantitatively separated into individual compounds 3a and 3b by column chromatography on silica gel. Detailed analysis of the ³¹P{¹H}, ¹H, ¹¹B NMR spectra of 1a,b—5a,b and 2D ¹H-¹H{¹¹B} and ¹¹B{¹H}-¹¹B{¹H} NMR spectra of 3a and 3b was performed. The structures of isomers 2a and 4a were confirmed by an X-ray diffraction study. According to the NMR and X-ray diffraction data, the isomerism of exo-nido-complexes 1a,b—5a,b is actually the cis—trans-isomerism of ligand arrangement in the octahedral coordination of the Os atom.