First total synthesis of two new heterocyclic compounds:Bretschneiderazines A and B

Facile synthesis of the two new natural heterocyclic compounds bretschneiderazines A（2） and B（3）,isolated from an extract of the stems of Bretschneidera sinensis,is reported.We employed the cyclization reaction of benzamide by directed lithiation and sequential treatment with sulfur and phosgene as key steps.All new compounds have been fully characterized by means of IR,¹H NMR,¹³C NMR,and HRMS.     

Novel organometallic aromatic polyester based on ferrocene

<正>A novel polyester containing ferrocenyl was prepared by low-temperature interface polycondensation of 1,1'-ferrocenedicarboxylic acid chloride with 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one(DHPZ),which is a twisted non-coplanar heterocyclic bisphenol-like monomer.The newly generated polymer was evaluated based on characterization of its solubility,viscosity measurements,elemental analysis,FTIR spectroscopy,differential scanning calorimetric and thermogravimetric studies.     

The p-adic quantum plane algebras and quantum Weyl algebra

Let q be a principal unit of the ring of valuation of a complete valued field K, extension of the field of p-adic numbers. Generalizing Mahler basis, K. Conrad has constructed orthonormal basis, depending on q, of the space of continuous functions on the ring of p-adic integers with values in K. Attached to q there are two models of the quantum plane and a model of the quantum Weyl algebra, as algebras of bounded linear operators on the space of p-adic continuous functions. For q not a root of unit, interesting orthonormal (orthogonal) families of these algebras are exhibited and providing p-adic completion of quantum plane and quantum Weyl algebras. The text was submitted by the authors in English.     

Espaces homogènes d'Einstein non-compacts

In this text, we consider the solvmanifolds obtained by an abelian extension of two-step nilmanifolds and obtain Einstein metrics (with negative scalar curvature) near to the symmetric spaces.     

Orthonormal q-bases associated to some continuous linear operators on (ℤ p ,K)

Let K be a complete valued field, extension of the p-adic field ℚ _p . Let q be a unit of ℤ _p , q not a root of unity and V _q be the closure of the set {q ⁿ /n ∈ ℤ} and let      

Regioselective synthesis and initial evaluation of a folate receptor targeted rhaponticin prodrug

To improve the therapeutic effect of rhaponticin(RHA),a folate receptor(FR) targeted RHA prodrug was designed and regioselectively synthesized by utilizing a hydrophilic peptide spacer linked to folic acid(FA) via a releasable disulfide linker.A series of biological evaluation was investigated in vitro and in vivo.The positive results of biological investigations warrant further preclinical study before this novel targeted chemotherapeutic is considered for clinical investigation.     

Optimization strategy and procedure for coal bed methane separation

Coal bed methane（CBM） has a huge potential to be purified to relieve the shortage of natural gas meanwhile to weaken the greenhouse effect.This paper proposed an optimal design strategy for CBM to obtain an integrated process configuration consisting of three each single separation units,membrane,pressure swing absorption,and cryogenics.A superstructure model was established including all possible network configurations which were solved by MINLP.The design strategy optimized the separation unit configuration and operating conditions to satisfy the target of minimum total annual process cost.An example was presented for the separation of CH₄/N₂ mixtures in coal bed methane （CBM） treatment.The key operation parameters were also studied and they showed the influence to process configurations.     

Variétés homogènes d'Einstein de courbure scalaire négative: Construction à l'aide de certains modules de Clifford

Using certain Clifford modules, we give a method for constructing many examples of homogeneous Einstein spaces with negative scalar curvature.     

Co9S8单晶片水热还原合成与磁性

以七水合硫酸亚钴 (CoSO4·7H2 O)和无水亚硫酸钠 (Na2 SO3)为原料 ,水合肼 (N2 H4·H2 O)为还原剂 ,在180℃水热处理 72h ,成功地合成了片状Co9S8单晶 .产物分别用X射线粉末衍射 (XRD)、透射电子显微镜 (TEM)和振动样品磁强计 (VSM )表征 .实验结果表明 ,产物主要由直径为 0 .8～ 1.5μm的片状Co9S8单晶组成 ,在室温下具有铁磁性 ,其饱和磁化率 (Ms)和矫顽力 (Hc)分别为 65emu/g和 3 3 3Oe     

Rank,term rank and chromatic number of a graph

Let G be a graph with a nonempty edge set, we denote the rank of the adjacency matrix of G and the term rank of G, by $\mathrm{rk}(G)$ and $\mathrm{Rk}(G)$, respectively. It was conjectured [C. van Nuffelen, Amer. Math. Monthly 83 (1976) 265–266], for any graph G, $\chi (G)?\mathrm{rk}(G)$. The first counterexample to this conjecture was obtained by Alon and Seymour [J. Graph Theor. 13 (1989) 523–525]. Recently, Fishkind and Kotlov [Discrete Math. 250 (2002) 253–257] have proved that for any graph G, $\chi (G)?\mathrm{Rk}(G)$. In this Note we improve Fishkind–Kotlov upper bound and show that $\chi (G)?\frac{\mathrm{rk}(G)+\mathrm{Rk}(G)}{2}$. To cite this article: S. Akbari, H.-R. Fanaï, C. R. Acad. Sci. Paris, Ser. I 340 (2005).