Study of Intramolecular Cyclization of N-styryl-oxo-cinnamides (Ⅱ)

lnthepreviouspaper',wereportedtheintramolecularcyclizationsofamide4anditscis-eneisomerinanattempttosynthesizehomoclausenamideandzetaclausenamide2.Inordertostudytherelationshipbetweenthestereochemistryandtheilltramolecularcyclizationofthisseriesofcompounds,theamides5(cis-oxirane,trans-ene)and8(cis-oxirane,cis-ene)wereprepared,andtheirintramolecularcyclizationswerereportedinthispaper.Theamide5withm.p.152.O-l54.O"CwasobtainedfromDarzen'scondensationofcompound3withPhCHOinMeOHatl5-2OoCwithMeO…     

Investigation of Absorption Spectra of Bis(alkylxanthato)-platinum(Ⅱ) Complexs

Being widely used as good ligands,xanthates and related compounds have been extensively investigated.However,reports on Pt(Ⅱ) xanthates have been sparse so far.Watt et al.reported the synthesis and characterization of Pt(S_2COR)_2(R=Me,Et),but did not provide any absorption spectra of these complexes.We prepared twelve platinum (Ⅱ) xanthate complexes and examined their absorption spectra in detail.     

Reaction of nickel(II) β-diketonates with hydroxylamine. Synthesis of nickel(II) complexes of mono-oximes of β-diketones (β-ketooximes)

Nickel(II) acetylacetonate or benzoylacetonate on treatment with hydroxylamine at O°C give adducts of the type Ni(β-diket)₂(NH₂OH) ₂ which on heating in refluxing ethanol afford β-ketooximato complexes of the type Ni(β-ketox)₂(H₂O)₂.     

Laser flash photolysis of fullerols of C_(60) and of C_(70) in aqueous solutions

Ｓｉｎｃｅｇｒａｍｑｕａｎｔｉｔｉｅｓｏｆｆｕｌｌｅｒｅｎｅｓｗｅｒｅｓｅｐａｒａｔｅｄｆｒｏｍｃａｒｂｏｎｓｏｏｔｓ,ｍａｎｙｓｔｕｄｉｅｓｈａｖｅｂｅｅｎｔｒｉｇｇｅｒｅｄｏｎｔｈｅｉｒｓｔｒｕｃｔｕｒｅｓ,ｐｒｏｐｅｒｔｉｅｓａｎｄｒｅａｃｔｉｏｎｓ.Ａｓｆｕｌｌｅｒｅｎｅｓｃａｎｐｒｏｄｕｃｅｖｅｒｙｈｉｇｈｑｕａｎｔｕｍｙｉｅｌｄｓｏｆｓｉｎｇｌｅｔｏｘｙｇｅｎｗｈｉｌｅｅｘｃｉｔｅｄｂｙｌｉｇｈｔ,ｍｏｒｅｉｎｔｅｒｅｓｔｈａｓｂｅｅｎｆｏｃｕｓｅｄｏｎｔｈｅｅｘａｍｉｎａｔｉｏｎｏｆｔ…     

Synthesis of (±)-Bimatoprost

A general synthetic approach has been developed for the synthesis of a key intermediate (6) that can be elaborated into several ophthalmic prostaglandins and their derivatives. Using these strategy, we have obtained (±)-bimatoprost (1) and its analog, (±)-homobimatoprost (5).     

Development of orientation during electrospinning of fibres of poly(ε-caprolactone)

We explore the influence of a rotating collector on the internal structure of poly(ε-caprolactone) fibres electrospun from a solution in dichloroethane. We find that above a threshold collector speed, the mean fibre diameter reduces as the speed increases and the fibres are further extended. Small-angle and wide-angle X-ray scattering techniques show a preferred orientation of the lamellar crystals normal to the fibre axis which increases with collector speed to a maximum and then reduces. We have separated out the processes of fibre alignment on the collector and the orientation of crystals within the fibres. There are several stages to this behaviour which correspond to the situations (a) where the collector speed is slower than the fibre spinning rate, (b) the fibre is mechanically extended by the rotating collector and (c) where the deformation leads to fibre fracture. The mechanical deformation leads to a development of preferred orientation with extension which is similar to the prediction of the pseudo-affine deformation model and suggests that the deformation takes place during the spinning process after the crystals have formed.     

Mechanism of the Deaquation of Aquopentaaminocobalt(III) Bromide

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｏｌｉｄ ｐｈａｓｅｄｅａｑｕａｔｉｏｎ ａｎａｔｉｏｎｒｅａｃｔｉｏｎ[Ｍ(ＮＨ3 ) 5(Ｈ2 Ｏ) ]Ｘ3 → [Ｍ(ＮＨ3 ) 5Ｘ]Ｘ2 +Ｈ2 Ｏ(Ｍ =Ｃｏ3 + ,Ｃｒ3 + ｏｒＲｕ3 + ａｎｄＸ =Ｃｌ- ,Ｂｒ- ｏｒＮＣＳ- )ｈａｓｂｅｅｎｗｉｄｅｌｙｓｔｕｄｉｅｄｓｉｎｃｅｔｈｅｎｉｎｅｔｅｅｎｓｉｘｔｉｅｓ .Ｔｈｅｔｈｅｒｍａｌａｎｄｋｉｎｅｔｉｃｐａｒａｍｅｔｅｒｓｈａｖｅｂｅｅｎｃａｌｃｕｌａｔｅｄａｎｄｔｈｅｄｉｆｆｅｒｅｎｔｍｅｃｈａｎｉｓｍｈａｓｂｅｅｎｐｒｏｐｏｓｅｄａｎｄｄ…     

Synthesis of the D-Galactopyranoside Derivative of C_(60)

ThefascinatingsbocturesandpropertiesoffullereneshaveoPeneduPanewfieldofchendstry.Inparticular,F.Wudletal.l'2haveshownthatwatersofubleC6ocomPoundsinhibittheHITVen-zymesprotease(HIVP)andreversetranscriPtase(HIVRT).IthasbeenafocusofstUdytoinvestigatethebiologicalactivitiesofthesenovelsubstances.Fortheirpossiblemedicaluses,tolinkC6omoleculetonaturalProductssuchassugars,pephdes,amioacides,andsoonisanimPortantmethodinthisfield.Vasella3reportedthefirstglucosidederivativeofC6o'InthispaPer,w…     

Synthesis of (±)-zearalenone

The aliphatic portion of (±)-zearalenone has been synthesised by a new simple route starting from 2,3-dihydropyran and 2-acetyl-γ-butyrolactone by employing dithiane for C-C bond formation. The final condensation of this segment with the aromatic part and subseqnet transformations led to (±)-zearalenone.     

Cyclic structure of the β(γ)-hydroxy-(mercapto)alkylimines of aldoses

In solutions in DMSO-d₆, the products from the condensation of ethanolamine and 1,2- and 1,3-aminopropanols with aldoses are mixtures of the - and -pyranose forms, whereas the -mercaptoethylimines of aldoses have the 1,3-thiazolidine structure. Glucose -mercaptoethylimine is characterized by ring-chain tautomerism involving the -pyranose and diastereomeric 1,3-thiazolidine tautomers.Military-Medical Academy, St. Petersburg, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1068–1071, August, 1998.     

Electrochemistry of microparticles of tris (2,2′-bipyridine) ruthenium(II) hexafluorophosphate

The electrochemical behaviour of tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate (Ru(II)) microparticles, immobilised on a graphite electrode and adjacent to an aqueous electrolyte solution, has been studied by cyclic voltammetry and an in situ spectroelectrochemical technique. The solid Ru(II) complex exhibits one reversible redox couple with a formal potential (E_f) of 1.1 V versus Ag¦AgCl. The continuous cyclic voltammetric experiments showed that the Ru(II) microparticles are stable during the electrochemical conversions. The in situ spectroelectrochemical study showed that the absorbance at 463 nm decreased due to the oxidation of Ru(II) to Ru(III). Upon reduction, the growth of absorbance at 463 nm was observed due to the formation of Ru(II) complex and this process was reversible.     

Synthesis of (±) Combretastatin

Combretastatin (1) is a new plant product isolated recently by Pettit et al ¹. from the South African tree, Combretum caffrum that possesses central nervous system antineoplastic activity and is being evaluated against several of National Cancer Institute's key evaluation systems. The structure of 1 was established on the basis of its spectral properties and confirmed by X-ray analysis. However, the absolute configuration and the synthesis of 1 have not been reported so far. As combretastatin is present in the plant in only 0.0008% and the isolation technique is much tedious, there is an urgent need for the synthesis of 1 for further evaluation of its activity. This prompted us t o report the first synthesis of (±)1.     

Reactivity of Geometric Isomers of (–)-Dichloropyridine(methyl-para-tolylsulfoxide)platinum(II) by Optical Rotatory Dispersion

The reactions of the optically active geometric isomers of the platinum(II) complex (–)-[Pt(Me-p-TolSO)(Py)Cl₂] with several nucleophilic reagents (Py, Ph₃PS, Ph₃P, Ph₃As, and Me₂SO) were studied by optical rotatory dispersion, IR spectroscopy, and ¹H and ³¹P NMR spectroscopy. A mechanism for the reaction is proposed.     

Langmuir-Blodgett films of phycobiliproteins (II) --Photoelectrochemical property of R-phycoerythrin

Through an electrochemical cell deposited with R-phycoerythrin (R-PE) monolayer on SnO2 optically transparent electrode (SnO2 OTE), charge transport phenomenon and the photoelectrochemical behavior of R-PE have been investigated. The experimental results indicate that the cell is able to generate photocurrent; moreover, the signal increases apparently in the presence of electron donor or acceptor in the electrolyte solution, showing that the photocurrent of R-PE would originate from its charge transfer. Further comparative test showed that the photocurrent came from the photo-induced charge separation property of the chromorphores attached covalently to the apoprotein of R-PE. The photocurrent spectrum of R-PE LB films verified the above viewpoint, from which the mechanism of photo-induced charge transfer of R-PE is suggested. The quantum yield for photoelectric conversion of R-PE LB films was measured to be φ520nm=3.4% and the photovoltage approached 400 mV. Moreover, the protein is stable for a long     

Determinations of combustion and formation enthalpies of C_(60)and C_(70)

Ｆｕｌｌｅｒｅｎｅｓａｒｅａｋｉｎｄｏｆｃａｒｂｏｎａｌｌｏｔｒｏｐｅｓｆｏｕｎｄｒｅｃｅｎｔｌｙ,ａｎｄｈａｖｅｄｉｓｔｉｎｃｔｉｖｅｓｔｒｕｃｔｕｒｅｓａｎｄｐｒｏｐｅｒｔｉｅｓ.Ｆｏｒｅｘａｍｐｌｅ,Ｃ60ｈａｓａｆｏｏｔｂａｌｌｌｉｋｅｃａｒｂｏｎｓｋｅｌｅｔｏｎｗｉｔｈ20ｓｉｘｍｅｍｂｅｒｅｄｒｉｎｇｓ,12ｆｉｖｅｍｅｍｂｅｒｅｄｒｉｎｇｓａｎｄａｌａｒｇｅｂａｌｌｓｈｅｌｌｌｉｋｅπｂｏｎｄｓｙｓｔｅｍ.Ａｌｔｅｒｎａｔｉｖｅｌｙ,Ｃ70ｈａｓａｎｅｌｌｉｐｓｏｉｄｌｉｋｅｃａｒｂｏｎｓｋｅｌ…     

Concept of Superbasicity of 1,8-Bis(dialkylamino)naphthalenes (“Proton Sponges”)

Superbasic properties of naphthalene protone sponges are determined by the p character of the unshared electron pair on the nitrogen atom of the dialkylamino group and by distortion of the n,* conjugation.     

Total Synthesis of (±)-Butyl Ester of Rosmarinic Acid

Rosmarinic acid, a well-known natural product firstly isolated from rosemary by Scarpati and Oriente in 19581, possesses various kinds of biological activities such as antioxidant2 and antibacterial3. Recently, the synthesis and biological activities of related compounds of rosmarinic acid have received much attention, such as 4, 4?′-O-di-β-D- glucopyranosyl rosmarinic acid4, methyl ester of rosmarinic acid5-6 and rabdosiin7. Butyl ester of rosmarinic acid 1 (Scheme 1) was isolated from Is…     

Mechanism of electrochemical synthesis of copper(II) β-diketonates

Formation of copper -diketonates in electrolysis of a solution of acetylacetone in acetonitrile in the presence of oxygen, with tetraethylammonium bromide as supporting electrolyte, was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 11, 2004, pp. 1804–1807.Original Russian Text Copyright © 2004 by Kostyuk.     

Characterization of self-assembled monolayers of thiols on Au(111)

Self-assembled monolayers (SAMs) of n-butanethiol, n-dodecanethiol and their equimolar mixture on Au(111) were prepared and characterized by ellipsometry, contact angle measurement, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results revealed that these SAMs are oriented ultrathin films with the thickness of nanometer scale, and the SAMs were influenced by the molecular chain length, the lattice orientation and cleanliness of the substrates. The surface of the longer chain SAM is hydrophobic. The thicknesses of three SAMs of n-butanethiol, n-dodecanethiol and their mixture revealed by ellipsometry and XPS are about 0.59 - 0.67nm, 1.60- 1.69 nm and 1.23 - 1.32nm, respectively. AFM images further demonstrated that the SAM formed by the mixture has some microdomains with two different thicknesses.     

Synthesis of 1,3-cyclic Monoalkyl(acyl)-racglycerothiophosphates of Uridine

Ｓｙｎｔｈｅｓｉｓｏｆ１，３－ｃｙｃｌｉｃＭｏｎｏａｌｋｙｌ（ａｃｙｌ）－ｒａｃｇｌｙｃｅｒｏｔｈｉｏｐｈｏｓｐｈａｔｅｓｏｆＵｒｉｄｉｎｅＣｈｅｎｇＸｉａｎｇＺＨＡＮＧ；ＲｕＹｕＣＨＥＮ；ＣｈｕＣｈｉＴＡＮＧ；ＨｕａｎＭｉｎｇＣＨＥＮ（Ｒｅｓｅａｒ...