Nucleophilic Substitution on 5-Nitrobenzofurazan-3-Oxide: A New Synthetic Route for Novel Benzofurazan-5, 5′-Oxybis 3, 3′-Dioxide and Benzofurazan-5, 5′-Thiobis-3, 3′-Dioxide

The nucleophilic substitution of the nitro group in 5-nitrobenzofurazan-3-oxide is studied undder soild-liquid phase-transfer catalysis (PTC) conditions.     

Thermal analysis of 5′-deoxy-5′-iodo-2′,3′-O-isopropylidene-5-fluorouridine

The melting temperature, melting enthalpy, and specific heat capacities (C _p) of 5′-deoxy-5′-iodo-2′,3′-O-isopropylidene-5-fluorouridine (DIOIPF) were measured using DSC-60 Differential Scanning Calorimetry. The melting temperature and melting enthalpy were obtained to be 453.80 K and 33.22 J g^?1, respectively. The relationship between the specific heat capacity and temperature was obtained to be C _p/J g^?1 K^?1 = 2.0261 – 0.0096T + 2 × 10^?5 T ² at the temperature range from 320.15 to 430.15 K. The thermal decomposition process was studied by the TG–DTA analyzer. The results showed that the thermal decomposition temperature of DIOIPF was above 487.84 K, and the decomposition process can be divided into three stages: the first stage is the decomposition of impurities, the mass loss in the second stage may be the sublimation of iodine and thermal decomposition process of the side-group C₄H₂O₂N₂F, and the third stage may be the thermal decomposition process of both the groups –CH₃ and –CH₂OCH₂–. The obtained thermodynamic basic data are helpful for exploiting new synthetic method, engineering design, and commercial process of DIOIPF.     

Synthesis of 2′-5′,3′-5′ linked triadenylates

2′-5′,3′-5′ Linked triadenylates have been synthesized by direct bisadenylylation of adenosine 2′ and 3′ hydroxyls with an adenosine 5′-phosphorochloridite followed by oxidation.     

Synthesis of 5-substituted-3-[(2′S,3′S)-3′-hydroxy-2′-hydroxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazoles and their epimers

5-Phenyl-3-[(2′R,3′S)-3′-hydroxy-2′-dimethoxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazole 10a and its epimer 11a, 5-methyl-3-[(2′R,3′S)-3′-hydroxy-2′-dimethoxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazole 10b and its epimer 11b were synthesized from cyanohydrin benzoates 8a, 9a and cyanohydrin acetates 8b, 9b, respectively, by treatment with hydroxylamine in methanol via intramolecular transacylation and subsequent cyclization of the corresponding amidoximes. Hydrolysis and reduction of the dimethoxymethyl groups in the above compounds gave the desired compounds 12a, 13a, 12b and 13b.     

Deoxyribonucleoside Cyclic 3′,5′-Phosphorofluondates

Abstract

The synthesis of nucleoside cyclic 3′,5′-phosphorofluoridates, so far not described compounds in the chemical literature, have been performed. As a key substrate we used 2′-deoxyribonucleoside cyclic 3′,5′-phosphorothioates (1) which have been obtained in this Laboratory several years ago.1     

基于1, 1′-苯乙炔-3, 3′, 5, 5′-四羧酸微孔铜配位聚合物的合成和气体吸附性质

本文报道了配合物[Cu₂(EBTC)(H₂O)₂]·8H₂O·DMF·DMSO(1, EBTC=1, 1′-乙炔基苯-3, 3′, 5, 5′-四羧酸根;DMF=N, N-二甲基甲酰胺;DMSO=二甲基亚砜)的合成、晶体结构和吸附性质。1拥有内径为0.85 nm和0.85 nm×2.15 nm的两种孔洞, 分别被6个和12个四羧酸根桥联的[Cu₂(CO₂)₄]螺旋桨式结构围绕, 并被EBTC连接成三维超分子结构, 该结构拥有可容纳溶剂分子的一维孔道。1为(3, 4)-连接的fof(sqc1575)拓扑结构, 具有非常大的孔体积, 其值高达单位晶胞体积的72.8%。去除溶剂分子后的1a表现出永久孔性, 其Langmuir表面积为2844 m²·g^-1, BET 表面积为1 852 m²·g^-1。它对H₂、CO₂、CH₄和C²H₂具有可观的气体吸附量和相对较高的吸附焓。特别是, 在迄今所有已报道的孔性金属-有机材料中, 1a在273 K、1.0×10⁵ Pa下, 表现出最高的乙炔吸附量(252 cm³·g^-1)和很高的吸附焓(吸附量为1 mmol·g^-1时的吸附焓为34.5 kJ·mol^-1)。     

Synthesis and Crystal Structure of 3′-Ethyl 5′-Methyl 1-Benzyl-4′-methyl-2-oxo-3′,4′-dihydrospiro-[indoline-3,2′-pyrrole]-3′,5′-dicarboxylate

The crystal structure of the title compound(C24H24N2O5, Mr = 420.45) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 8.991(1), b = 11.166(1), c = 11.169(1) , α = 91.413(2), β = 105.887(2), γ = 90.992(2)°, V = 1077.8(2) 3, Z = 2, Dc = 1.296 g/cm3, F(000) = 444, μ(MoKα) = 0.091 mm-1, the final R = 0.0466 and wR = 0.1507 for 4185 observed reflections(I 2σ(I)). The single-crystal X-ray diffraction data indicated intermolecular C(17)–H(17)O(4), C(5)–H(5)… O(4) hydrogen bonds and C–H…π interaction in the structure.     

Synthesis of 3-(3′-Acetyl-5′-aroyl-1′,3′,4′-oxadiazolyl-2′)-chromones

A general method has been proposed for synthesizing 3-(3-acetyl-5-aroyl-1,3,4-oxadiazolyl-2)-chromones that has been based on conversion of 3-formylchromones to acylhydrazones and of theacylhydrazones into the heterocyclic chromones.     

Synthesis,Crystal Structure,and Biological Activity of Two Complexes based on 5-hydroxy-4′-methoxyisoflavone-3′-sulfonate

Russian Journal of Coordination Chemistry - Two metal complexes [Mn(H2O)6(C16H11O7S)2] · 2H2O (I) and Al(H2O)3(C16H11O7S) · 2H2O (II) were synthesized by reaction of the sodium...     

棒丝氨酸的全合成研究 Ⅰ.从D-葡萄糖合成3-[(3′R,5′S)-7′-氧代-1′-氮杂-4′-氧杂双环[3.2.0]-庚-3′-基]-3-O-苄基-(2S,3S)-丝氨酸及其(3′R,5′R)-差向异构体

以D-葡萄糖为原料经侧链氨基酸合成,与β-内酰胺缩合,嗯唑烷环合和除保护基等反应合成了棒丝氨酸的O-苄基衍生物,3-[(3′R,5′S)-7′-氧代-1-氮杂-4-氧杂双环[3.2.0]-庚-3′-基]-3-O-苄基-(2S,3S)-丝氨酸(17)及其(3′R,5′R)差向异构体(18)。     

Synthesis of 5′-amino- and 5′-azido-2′,5′-dideoxy nucleosides from thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione

Summary Thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (4) was silylated and condensed with methyl 5-azido-2,5-dideoxy-3-O-(4-methylbenzoyl)-D-erythro-pentofuranoside (2) in the presence ofTMS triflate to afford the corresponding protected nucleoside6 and acyclic nucleoside7. Deprotection of6 with MeONa/MeOH at room temperature gave 1-(5-azido-2,5-dideoxy--D-erythro-pentofuranosyl)-thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (8) and the corresponding anomer9, whereas compound7 yielded 5-azido-2,5-dideoxy-1-(2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-1-yl)-1-O-methyl-D-erythro-pentitol (10) under the same reaction conditions. 1-(5-Amino-2,5-dideoxy--D-erythro-pentofuranosyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (11) was obtained on treating9 with Ph₃P in pyridine followed by hyrolysis with NH₄OH. The anomeric nucleosides14 and15 and the corresponding acyclic nucleoside16 were obtained when4 was trimethylsilylated and condensed with methyl 2-deoxy-3,5-di-O-(4-methylbenzoyl)-D-erythro-pentofuranoside (3) followed by deprotection with MeONa in MeOH. Compounds8 and9 were also obtained when the anomeric mixture14/15 was treated with a mixture of NaN₃, Ph₃P, and CBr₄ in dryDMF at room temperature.On leave from Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt     

A general approach to nucleoside 3′- and 5′- monophosphates

Diallyloxyphosphorylation of nucleoside hydroxyls followed by palladium(0)-catalyzed deallylation provides a new, general method for the preparation of the 3′- and 5′-monophosphates.     

Application of Ultrasonic Waves: An Improved Synthesis of 5′-Deoxy-5′-cyano-2′,3′-isopropylidene Adenosine

The title compound is prepared in excellent yield by the reaction of sodium cyanide with 1 in the presence of ultrasonic waves.     

3，3′，5，5′—四甲基联苯胺—β—环糊精包合物性质的研究

3,3′,5,5′－四甲基联苯胺（TMB）是一种联苯胺类色原试剂,具有良好的氧化还原性,将TMB包合于β－环糊精腔内,由于超分子化合物的形成而使TMB的反应性有所改变。本文采用紫外－可见吸收光谱和电化学方法研究了TMB和β－环糊精形成的包合物的性质。研究表明形成包合物后,无论在溶液体系还是在电极表面,其氧化还原活性得到明显的加强。     

Synthesis of 5′-deoxy-5′-[18F]fluoro-adenosine by Radiofluorination of 5′-deoxy-5′-haloadenosine Derivatives

5-Deoxy-5-[¹⁸F]fluoro-adenosine was synthesised by nucleophilic radiofluorination reactions of 5-deoxy-5-haloadenosines. The homogeneous isotope exchange in 5-deoxy-5-fluoro-adenosine was also investigated. The conversion of these reactions was found to be rather low and depends on the strength of the halogen-carbon bond: 0.248% for chloride-, 0.488% for bromide- and 1.070% for iodide-derivative; there was no reaction observed in the case of fluoro-compound.     

5，8，5′，8′-二甲氧基-3，3′-二亚甲基-2，2′-双喹啉的合成

2-氨基-3,6-二甲氧基苯甲醛与1,2-环己二酮发生Fried lander缩合反应合成了新化合物5,8,5,′8′-二甲氧基-3,3′-二亚甲基-2,2′-双喹啉,其结构经UV,1H NMR,IR和MS表征。