One-pot synthesis of 6H-2,2a1,3-triazaaceanthrylen-6-ones and 6H-2,2a1,4-triazaaceanthrylen-6-ones via tandem cyclization strategies

Two operationally simple one-pot protocols have been developed for the synthesis of 6H-2,2a¹,3-triazaaceanthrylen-6-ones and 6H-2,2a¹,4-triazaaceanthrylen-6-ones. The first Pd-catalyzed tandem cyclization of imidazo[1,2-a]pyrimidines/imidazo[1,2-a]pyrazines with 2-chlorobenzaldehydes could proceed in aqueous medium under air, affording the desired products in moderate to good yields. The molecular structures of products 3i and 5b were confirmed by X-ray crystallographic analysis.     

Study on the synthesis of 6-alkylaminouridines via the nucleophilic aromatic substitution reaction of 6-cyanouridine derivatives

6-Cyanouracil derivatives underwent direct substitution reactions with selective primary amines in the presence of N,N-dimethylaminopyridine as a catalyst to give the corresponding 6-alkylaminouracils. This reaction provides a facile access to versatile 6-alkylaminouridine derivatives.     

Darstellung und Kristallstruktur von K6[Al2O6] und Rb6[Al2O6]

Preparation of Crystal Structure of K₆[Al₂O₆] and Rb₆[Al₂O₆] Colourless single crystals of K₆[Al₂O₆] have been prepared from intimate mixtures of KAlO₂ and K₂O (550°C, 90 d). The structure determination from four-circle diffractometer data (MoKα , 742 I_o(hkl), R = 2.2%, R_w = 2.1%) confirms the space group C2/m with Z = 2; a = 698.25 pm, b = 1 103.54 pm, c = 646.49 pm, β = 102.49°. Colourless single crystals of hitherto unknown Rb₆[Al₂O₆] have been prepared from intimate mixtures of RbAlO₂ and Rb₂O (520°C, 120 d). The structure determination from four-circle diffractometer data (MoKα , 1 240 I_o(hkl)) results in the residual values R = 7.2%, R_w = 4.9%; space group C2/m; a = 725.92 pm, b = 1 143.33 pm, c = 678.06 pm, β = 104.05°; Z = 2. K₆[Al₂O₆] and Rb₆[Al₂O₆] are isostructural with K₆[Fe₂O₆]. A characteristic structure unit is the anion [Al₂O₆]^6? consisting of two edge-sharing [AlO₄] tetrahedra. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Madelung Part of Lattice Energy (MAPLE) and the Charge Distribution (CHARDI) are calculated and discussed.     

The Benzoylation of 6-Methyluracil and 5-Nitro-6-methyluracil

6-Methyluracil and 5-nitro-6-methyluracil react with variable molar quantities of benzoyl chloride in acetonitrile-pyridine at room temperature to give I-N, 3-N-dibenzoyl-6-methyluracil 3b and l-N-benzoyl-5-nitro-6-methyluracil 4b. The reactive rates of debenzoylation of 3b and 4b were investigated.     

RNA表观遗传修饰——N~6-甲基腺嘌呤与植物的生长发育

RNA表观遗传修饰N~6-甲基腺嘌呤(m~6A)是真核生物信使RNA(mRNA)上存在的最为广泛的中间化学修饰。它在哺乳动物中存在较为广泛,证实m~6A为mRNA上的动态可逆化修饰,它由甲基转移酶复合物(编码器)催化形成,同时可以被去甲基酶(消码器)氧化去甲基;m~6A可以被结合蛋白(读码器)识别,进而调控mRNA的剪接、稳定性、翻译、出核等。相较之下,m~6A在植物中的研究较少。本文将简要回顾目前m~6A的研究进展,重点综述m~6A在植物中的研究结果,展望m~6A在植物生长发育和应对外界刺激时的潜在重要功能。     

C6H6分子振动能谱的涨落统计特征

The statistical properties of vibrational energy levels in C6H6 are analyzed. The results show that they belong to a completely different type, of which the spectral rigidity is larger but the fractal dimensional function is smaller than both the Wigner law and Poisson law, and this new statistical property is called the low Poisson law. In fact, this special statistical property reflects the speciality in the structure of C6H6 in a way.     

Zur Kristallstruktur von LiPdGaF6, RbPdAlF6 und K1,06Pd0,95Fe1,05F6

The Crystal Structure of LiPdGaF₆, RbPdAlF₆ and K_1.06Pd_0.95Fe_1.05F₆ Single crystals of LiPdGaF₆ (blue; trigonal, P31 c-D_3d² (No. 163), a = 505.72(2), c = 923.7(2) pm; LiCaAlF₆-Type [1]), RbPdAlF₆ (violet; orthorhombic, Pnma-D_2h¹⁶ (No. 62), a = 729.0(1), b = 711.1(1), c = 1006.5(2) pm; CsAgFeF₆-Type [2]) and K_1.06Pd_0.95Fe_1.05F₆ (greenish-blue; tetragonal, P4₂/mbc-D_4h¹³ (No. 135), a = 1 279.07(7), c = 800.2(1) pm; K_1,08MnFeF₆-Type [3]; four cycle diffractometer data, Siemens AED2) are obtained by heating the binary fluorides in sealed Pd-tubes under dry argon [solid state reaction, T ≈ 650, t ≈ 19 d (39 d, 24 d)].     

二环己基并18冠6的制备方法

二苯并-18－冠-6;二环己基并18冠6的制备方法     

Electron Transfer Reaction between M-C_6H_6 and M~ -C_6H_6 Complexes in the Gas Phase: Density Functional Theory Study

Significant progress has been made in understanding the nature of the transition state andthe paths for electron transfer, especially the influences of environmental factors and themolecular properties on the electron transfer rate. These classical and semi-classical, aswell as quantum-mechanical theory, have been very successful in rationalizing severalstructure-reactivity relationships and in predicting novel features of reactivity. Thesemodels established some links between the electron tra…     

Synthesis of mono-substituted derivatives of 6-aminoquinoline

Several 6-aminoquinoline derivatives,which could be used in drug design,have been synthesized.The reaction conditions were comparatively studied,and the p-chloroaniline was used as optimum oxidant in Skraup-Doebner-Von Miller reaction.The nitro group was reduced effectively by SnCl₂ with no halo-removed occurred.     

NEW 6-ETHOXYQUINOLINES AS SIMPLE OPTOQUINE ANALOGUES

ABSTRACT

Reaction of 6-ethoxylepidine (6-ethoxy-4-methylquinoline) with strong base and electrophiles leads to new derivatives, as possible optoquine analogues.     

A Determination of 6-Mercaptopurine and 6-Thio-Guanine By Anodic Differential Pulse Voltammetry

Abstract

The anodic oxidation of 6-mercaptopurine and 6-thioguanine has been studied on a rotating and stationary disk electrode of glassy carbon, using d.c. and differential pulse potential program. Conditions have been found for determination of these substances by anodic differential pulse voltammetry on a rotating disk electrode, with a detection limit of about 2 × 10^?5 mol 1^?1.     

A New Synthetic Route for Preparation of 2-Chloro-6-fluoro-benzonitrile and 2-Chloro-6-fluorobenzoic Acid

An effective synthetic route for preparation of 2-chloro-6-fluorobenzonitrile, 2-chloro-6-fluorobenzamide and 2-chloro-6-fluorobenzoic acid has been described. It includes diazotization,fluorination, ammoxidation and hydrolysis reactions.     

Growth and Optical Properties of Sr_6YbSc(BO_3)_6 Crystal

1INTRODUCTION As is well known,the Yb3 ion has some advan-tages in comparison with Nd3 as laser active ion,for it has only two manifolds,i.e.,the ground2F7/2state and the excited2F5/2state.There is no excited state absorption reducing effective laser cross-section,no concentration quenching,no up-conversion,and three or four times longer emission lifetime than Nd3 ion.Yb3 ion exhibits a strong and broad ab-sorption band at ca.970nm and can be easily pumped with InGaAs diode lasers.The …     

6α-羟基紫杉醇的合成

以紫杉醇为原料,经过羟基保护、磺酸化、烯化、双羟基化、构型翻转、去除保护基,得到6α-羟基紫杉醇。目标化合物和中间体的结构经1H NMR、MS确证,总收率为3.97%。     

Optimized Procedure for the Synthesis of 6‐Azido‐6‐deoxy‐galactopyranosides From 6‐O‐Tosyl‐galactopyranosides

The reaction conditions for preparation of 6‐azido‐6‐deoxy‐glycoside remain elusive, although there are many successful cases in hand. After careful investigation of the reaction conditions, a practical procedure for the preparation of 6‐azido‐6‐deoxy‐galactopyranoside derivatives was demonstrated.     

Synthesis and Crystal Structure of CuIIMoIVF6 and CrIINbIVF6 (LT Form)

The fluorides CuMoF₆ and CrNbF₆ are triclinic, isostructural with CuSnF₆. Their crystal structures were solved in the space group P1, by the Rietveld method using the data of their X-ray powder patterns. Both crystal structures can be described as a three-dimensional framework of alternating 6 corner-sharing [M^IIF₆] and [M′^IVF₆] octahedra (M^II = Cr, Cu; M′^IV = Nb, Mo) with ferrodistortive Jahn-Teller ordering.     

Synthesis of 6, 9, 11-Trihydroxy-6a, 12a-dehydrorotenoid

6, 9, 11-Trihydroxy-6a, 12a-dehydrorotenoid 1 (coccineone B) was synthesized from 2-hydroxybenzaldehyde 2 and phloroglucinol.     

二氢卟吩e~6-6-酰胺衍生物的合成

首次报道了以蚕沙叶绿素初提物为基础原料,经酸降解得到含焦脱镁叶绿酸a和脱镁叶绿酸a的混合物,不经分离直接与胺类反应使脱镁叶绿酸a的戊酮环(V)裂开,合成得11种二氢卟吩e~6-6-酰胺衍生物。提供了一种合成二氢卟吩酰胺的新方法。