Synthesis of Some Novel Phenyl Substituted Oxothiazolidin- 1’’,3’’,4’’-thiadiazolo-[3’,4’-b]thiazoline of 3β-Substituted Cholestane

Three title compounds 4a—4c have been synthesized by the cyclodehydration of 1’-benzylidine-4’-(3β-substituted-5α-cholestane-6-yl)thiosemicarbazones 2a—2c with thioglycolic acid followed by the treatment with cold conc. H2SO4 in dioxane. The compounds 2a—2c were prepared by condensation of 3β-substituted-5α-cholestan- 6-one-thiosemicarbazones 1a—1c with benzaldehyde. These thiosemicarbazones 1a—1c were obtained by the reaction of corresponding 3β-substituted-5α-cholestan-6-ones with thiosemicarbazide in the presence of few drops of conc. HCl in methanol. The structures of the products have been established on the basis of their elemental, analytical and spectral data.     

Igor’ Vladimirovich Rybal’chenko turns sixty

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Igor’ Vladimirovich Rybal’chenko turns sixty     

Igor’ Vladimirovich Pletnev’s 50th birthday

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Igor’ Vladimirovich Pletnev’s 50th birthday     

Birthday of Tat’yana Anatol’evna Maryutina

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Birthday of Tat’yana Anatol’evna Maryutina     

1,3-Dipolar cycloaddition of alkenes to 3’-azido-3’-deoxythymidine as a route to 3’-deoxythymidin-3’-yl derivatives

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Synthesis of 5-Substituted-3-[(2’R,4’R)-4’-Hydroxy-2’-hydroxymethyltetrahydrofuran-4’-yl]-1,2,4-oxadiazoles and Their Epimers

The syntheses of 5-substituted-3-[( 2' R, 4' R)-4 ' -hydroxy-2 ' -hydroxymethyltetra-hydrofuran-4' -yl]D-1 ,2, 4-oxadiazoles and their epimers were accomplished with the aid of th construction of 1,2, 4-oxadiazoles by condensation of O-acylated cyanohydrins with hydroxylamine via intramolecular transacylation and subsequent cyclization.     

Influence d’alcools aliphatiques sur l’adsorption d’acides aminés sur charbon actif

Adsorption of aqueous solution of two amino acids – phenylalanine (Phe) and tyrosine (Tyr) – on powdered activated carbon (PAC) has been studied in the presence of linear or branched alcohols. Methanol has no influence on the adsorption. For the other alcohols, the adsorption decreases when the alcohol chain gets longer, from ethanol to 1-propanol, up to 85 %. Alcohol branching reduces this phenomenon. Adsorption kinetics have been tested according two models, allowing good representation of results and determination of kinetic constants.     

‘Verification’ versus ‘validation’: a terminological comparison

The present diversity in the definitions and relations of ‘verification’ and ‘validation’ is impractical for such transdisciplinary concepts. General dictionaries, international special language vocabularies and minor lists show that the respective recent formulations by the International Organization for Standardization (ISO) and the Joint Committee for Guides in Metrology (JCGM) are the most quoted. The characteristics of these concepts are elucidated terminologically, and separate concept systems are made for ISO and JCGM to arrive at a preference for a generic rather than an associative relation.     

Honda’s thermobalance

Kotaro Honda (2/23/1870–2/12/1954) graduated from the Department of Physics, Tokyo Imperial University in 1897. Between 1907 and 1911, he stayed in Europe, and spent the majority of his time at Göttingen University to study physical metallurgy under Professor Gustav Tammann. In 1911, he returned to Japan and was nominated professor of physics at Tohoku Imperial University, Sendai. An university-affiliated institute for research on iron and steel was established on a permanent basis in 1919, and the institute developed to the Research Institute for Iron, Steel, and Other Metals (RIISOM, KINKEN in Japanese) in 1922. Professor Honda served as the Director of the Institute until 1933. The RIISOM was reorganized as a national collaborative research institute named Institute for Materials Research in 2001. Professor Honda and his colleagues achieved distinguished research works of physical metallurgy, in which thermoanalytical techniques such as differential thermal analysis (DTA), thermodilatometry and thermomagnetometry were utilized effectively. Professor Honda also played an important role in the field of thermogravimetry (TG) by means of the first development of the thermobalance. In the present paper, Honda’s original thermobalance, various modifications carried out by his school, the commercialized Honda’s thermobalance and other related matters are briefly summarized.     

’95新春寄语

本刊改为月刊已满一载。在全国广大作者、读者的关心和支持下,本刊在保留原有栏目特色的基础上,又增设了几个新栏目,并试探着为在校的中学生出“增刊”或在正刊某期中为他们开辟园地。     

A Luminescent Tb(Ⅲ)-4,4’,4’’-nitrilotribenzoate Compound with a Three-dimensional Structure

A coordination polymer of [Tb(ntb)]n(1) based on 4,4’,4’’-nitrilotribenzoate ligand(ntb3–) was synthesized. Compound 1 crystallizes in monoclinic system, space group C2/c with a = 13.7318(4), b = 27.5628(9), c = 5.4046(2) ?, β = 111.142(3)°, V = 1907.88(12) ?3, Z = 4, C21H12NO6Tb, Mr = 533.24, Dc = 1.856 g/cm3, μ = 3.745 mm–1, F(000) = 1032, the final R = 0.0184 and wR = 0.0456 for 1883 observed reflections with Ⅰ > 2s(Ⅰ). In compound 1, the eight-coordinated Tb(III) atoms are bridged by carboxylate groups of ntb3– ligands to generate a one-dimensional Tb-carboxylate chain, which is further linked by the ntb3– ligands to form a three-dimensional structure. Compound 1 exhibits characteristic Tb(Ⅲ) luminescent emissions in the solid state.     

Optimisation d’une sélection in vitro d’enzymes

Optimisation of an in vitro enzyme selection. Isolation of a catalyst for a given chemical reaction may be achieved by in vitro selection of enzymes from a protein library. Here, we investigate the polymerisation reaction on filamentous phage and the cross-linking of substrate on phage to optimise an in vitro selection for DNA polymerase activity. The efficiency of the optimised selection is measured by enrichment factors up to 3.8 × 10³, the highest described so far for an in vitro selection of proteins for catalysis. It should be useful for directed polymerase evolution towards novel catalytic activities. To cite this article: E. Orsi, J.-L. Jestin, C. R. Chimie 6 (2003).     

Radiolytic stability of N,N-didodecyl-N’,N’-diethylhexyl diglycolamide

The radiolytic degradation of N,N-di-dodecyl-N′,N′-di-2-ethylhexyl-3-oxapentane-1,5-diamide (D³DEHDGA) was studied at various absorbed doses of γ-radiation. The degradation was assessed by measuring the variation in the extraction behavior of Am(III) in irradiated solvent systems composed of neat D³DEHDGA or 0.1 M D³DEHDGA/n-dodecane in the presence and absence of nitric acid. The distribution ratio of americium (D _Am(III)) decreased with increase of absorbed dose. The presence of n-dodecane and nitric acid enhanced the radiolytic degradation of the solvent. The third phase formation behavior of Nd(III) decreased with increase of absorbed dose and the third phase was not observed at absorbed doses above 100 kGy. The recovery of Am(III) from the irradiated system was near quantitative in five contacts. The study revealed that the extraction and stripping behavior of the irradiated solvent was quite satisfactory for partitioning of minor actinides from real wastes.     

Manganese Dioxide Mediated Stereoselective, One-step Synthesis of Novel Steroidal (6R)-Spiro-1’,2’,4’-triazoline-3’-thiones

Oxidative cyclization of 5α-cholestan-6-one thiosemicarbazone (1), its 3β-chloro (2) and 3β-acetoxy (3) analogues with active manganese dioxide at room temperature afforded selectively the corresponding (6R)-spiro-1’,2’,4’-triazoline-3’-thiones 4—6. This synthesis has the advantages of mild reaction conditions, easy handling, easily available reagent and high yields. The products have been characterized by analytical and spectral data.     

Two Cd(Ⅱ)-biphenyl-3,3’-disulfonyl-4,4’-dicarboxylate-2,2’-bipyridine Compounds: Structures and Luminescence

Two coordination polymers based on the mixed ligands of biphenyl-3,3?-disul-fonyl-4,4?-dicarboxylate(BPDSDC4–)and 2,2?-bipyridine(2,2?-bpy),{[Cd(BPDSDC)0.5(2,2?-bpy)(H2O)]·(H2O)}n(1)and{[Cd(BPDSDC)0.5(2,2?-bpy)2]·(H2O)}n(2)were synthesized.Both compounds crystallize in the monoclinic system,space group P21/n.For 1,a=7.5737(2),b=17.4284(5),c=13.5982(5)?,β=90.788(3)°,V=1794.76(10)?^3,Z=4,C17H15N2O7SCd,Mr=503.77,Dc=1.864 g/cm^3,μ=1.378 mm^?1,F(000)=1004,the final R=0.0299 and wR=0.0644 for 3137 observed reflections with I>2s(I).For 2,a=13.3097(2),b=10.66240(10),c=17.6583(3)?,β=91.779(2)°,V=2504.74(6)?^3,Z=4,C27H21N4O6SCd,Mr=641.94,Dc=1.702 g/cm^3,μ=1.008 mm^?1,F(000)=1292,the final R=0.0244 and wR=0.0583 for 4594 observed reflections with I>2s(I).The Cd(II)atoms in both compounds are six-coordinated.In 1,the Cd(2,2?-bpy)units are connected by BPDSDC4–ligands to generate a one-dimensional(1D)ribbon structure.The 1D ribbons are linked by the hydrogen bonds and π···π interactions to give a three-dimensional(3D)structure.In compound 2,the Cd(2,2?-bpy)2 units are linked by the BPDSDC^4–ligands to form a 1D chain.Compounds 1 and 2 show luminescent emissions.     

Total Syntheses of 16a’-Homoleurosidine and 16a’-Homovinblastine

Vinblastine has been used in clinic as an anti-cancer agent. Due to its high cytotoxity, generation of vinblastine congeners as safe anti-cancer agents is always the interesting topic in medicinal chemistry. In the previous synthesis of vinblastine, it has been found that a higher energy conformation of vinblastine lacking cytotoxity and inhibition against tubulin polymerization, can be converted to its lower energy natural conformation on heating to 110 oC. The high temperature (110 oC) othe…