Synthesis of 2′-deoxy-2′-fluororibo- and 2′-deoxy-2′,2′-difluororibonucleosides derived from 6-(het)aryl-7-deazapurines

A series of novel sugar-modified derivatives of cytostatic 6-hetaryl-7-deazapurine ribonucleosides (2′-deoxy-2′-fluororibo- and 2′-deoxy-2′,2-difluororibonucleosides) bearing an aryl or hetaryl group in position 6, was prepared and screened for biological activity. The fluororibo derivatives were prepared by aqueous palladium catalyzed cross-coupling reactions of the corresponding 6-chloro-7-deazapurine 2′-deoxy-2′-fluororibonucleoside 11 with (het)arylboronic acids. The key intermediate 11 was prepared by a six-step sequence from the corresponding arabinonucleoside by selective protection of 3′- and 5′-hydroxyls by acid-labile groups followed by stereoselective S_N2 fluorination and deprotection. The difluororibo-series was prepared by non-stereoselective glycosidation of 6-chloro-7-deazapurine with benzoyl-protected 2-deoxy-2,2-difluoro-d-erythro-pentofuranosyl-1-mesylate followed by cross-couplings, separation of anomers and deprotection. The title nucleosides did not show considerable cytostatic or antiviral activity.     

Efficient Preparative Rentes to 6,6′-Dibromo-2-2′-bipyridine and 6-Bromo-2,2′-bipyridine

The preparation of 6,6′-dibromo-2,2′-bipyridine and 6-bromo-2,2′-bipyridine are described. The dibromo compound was prepared by way of an improved cuprate synthesis resulting in a 72% yield. The monobromo species was prepared from the dibromo compound by way of metal-halogen exchange in 88% yield.     

An Improved Synthesis of 2′-Hydroxy-3′,4′,6′-trimethoxyacylophenones

A wide variety of 2′-hydroxypolymethoxyacetophenones and propiophenones, e.g. 1a and 1b are used in the synthesis of flavone and ehromone natural products.¹ Repeated attempts to prepare 1a and 1b by reacting 1,2,3,5-tetramethoxybenzene 2 with acetyl or propionyl chlorides and AlCl₃ in ether² gave products which were difficult to purify.³ We traced the problem to ring-ethoxy contaminants which were isolated and tentatively identified as 3a and 3b.     

6，6′-二硝基-2，2′-联苯酸铀(Ⅵ)配聚物

Uranium(Ⅵ) complex {[UO₂((R，S)-1，1′-biphenyl-6，6′-dinitro-2，2′-dicarboxylate)(H₂O)](H₂O)} was obtained by the hydrothermal treatment of UO₂(NO₃)₂·6H₂O with (R，S)-6，6′-dinitro-biphenyl-2，2′-dicarboxylic acid(BSNCA) (L) in water at 180 ℃ in Pyrex tube. The crystal belongs to triclinic system， space group P1， with a=0.903 45(14) nm， b=1.024 43(16) nm， c=1.058 95(16) nm， α=90.411(3)°， β=112.934(3)°， γ=92.554(3)°. CCDC: 659613.     

Über das analytische Verhalten der Psychopharmaka 2-Phenyl-2-äthyl-4-hydroxymethyl-1,3-dioxolan und 2-Methyl-2- (p-chlor-phenyl) -4-hydroxymethyl-1,3-dioxolan

Analytical and Bioanalytical Chemistry -     

Synthesis of N-Aryl-2-(1′,6′-dihydro-6′-pyridazinone-3′-carbonyl) Thiosemicarbazides and Their Related Heterocyclic Compounds

Introduction Somepyridazineshavebeenexaminedforac- tivityagainstsporozoanandflagellateparasitesand forantiamebicactivity[1]. 6-Aryl-4,5-dihydro-3(2H)-pyridazinonesex- hibitvariousbiologicalpropertiesincludingreduc- tionofbloodpressure,inhibitionofplateletaggre- gation,antiinflammation,andstrongplateletag- gregationinhibitingactioncoupledwithahypoten- siveaction.Italsopossessesweakpositiveinotrop- icactivityforthemanagementofcongestiveheart failure.Threepara-substitueddihydropyridazi- nonesare…     

Microwave promoted one-pot synthesis of 3-(2′-amino-3′-cyano-4′-arylpyrid-6′-yl)coumarins

A facile procedure for the synthesis of 3-(2′-amino-3′-cyano-4′-arylpyrid-6′-yl)coumarins are being reported starting from 3- acetylcoumarin,aromatic aldehydes and malononitrile.The reactions were carded out on microwave irradiation in good yield with short time and easy work-up.The structures of all the compounds have been confirmed on the basis of their analytical,IR,~1H NMR, and mass spectral data.     

2′－胺基－6′－（二乙胺基）萤烷的晶体结构研究

２′－胺基－６′－（二乙胺基）萤烷的晶体结构研究陈红丽，孙命，刘景旺，刘小兰，缪方明（天津师范大学晶体化学研究所天津３０００７４）关键词萤烷，晶体结构萤烷类化合物是现今各国集中研究的一类压敏色素，用于压敏复写纸的制造，特别是随着电子技术和计算机技术的...     

Synthesis of 5,5′-Dialkyl-6,6′-dichloro-2, 2′-bipyridines

5,5′-Dialkyl-6,6′-dichloro-2,2′-bipyridines were synthesized starting from 3-substituted 2-chloro-6-iodopyridines using Pd-catalyzed coupling conditions. 6-Alkyl-3,5-dichloro-2H-1,4-oxazin-2-ones were excellent precursors for the synthesis of these functionalized 2-iodo-6-chloropyridines.     

基于2，2′，6，6′-联苯四酸的两个新配位聚合物的水热合成与晶体结构

通过2,2′,6,6′-联苯四酸与相应金属硝酸盐和第二配体的水热反应合成了2个具有不同结构的配位聚合物[Co(bta)0.5(2,2′-bipy)(H2O)]n(1)和{[Cd2(bta)(H2biim)2(H2O)].H2O}n(2)(H4bta=2,2′,6,6′-联苯四酸,2,2′-bipy=2,2′-联吡啶,H2biim=1H,1′H-2,2′-联咪唑),并测定了其晶体结构。1和2都是一维链结构,并且1和2都属于单斜晶系,P21/c空间群。bta配体在1和2中分别采取η6,μ4-六齿和η5,μ4-五齿配位模式,同时bta配体中2个苯环的夹角在化合物1和2中分别是64.80°和64.86°。1与2分别在170℃和120℃以下保持热稳定性。     

Darstellung von 2′,3′-Dideoxy-2′-hydroxymethyl-nucleosiden

Zusammenfassung Die Synthese von geschützten 2,3-Dideoxy-2-hydroxymethyl-nucleosiden wird beschrieben. Die durch ein Mehrstufenverfahren aus Isopropylidenglycerol erhaltenen Nucleoside können als Bausteine zur Darstellung von Oligonucleotiden verwendet werden, deren 2- und 5-Positionen über eine Etherbrücke verbunden sind.

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Synthesis of 2,3-dideoxy-2-hydroxymethyl nucleosides

Summary The synthesis of protected 2,3-dideoxy-2-hydroxymethyl nucleosides is presented. The nucleosides, obtained in a multi-step procedure starting from isopropylideneglycerol, may be used as building blocks for the synthesis of 2,5-ether linked oligonucleotides.

     

Silylation of 5′-O-DMT-2′-Deoxyncleosides Using Dibenzo [18] Crown-6 and PTC

3′O-silylated derivatives of 5′-O-DMT-2′deoxynucleoside (2) were synthesized in high yield by reaction of 5′-O-DMT-2′-deoxynucleosides (1) with tert-butyl dimethylsilylchloride using sodium hydride, benzyltriethylammonlum chloride [TEBA] and a catalytic amount of dibenzo-[18]-crown-6 [DB-18-C-6] or 15-crown-5 [15-C-51 under mild reaction conditions.     

4，4′-联吡啶-2，2′，6，6′-四羧酸与含氮配体构筑的金属配合物的结构和荧光性质

用水热法合成了2个化合物[M2(L)(phen)2(H2P)2]·6H2O[M=Ni(1),Zn(2),H4L=4,4'-联吡啶-2,2',6,6'-四羧酸,phen=1,10-邻菲咯啉],并进行了元素分析、IR及X-射线单品结构测定等表征.晶体结构解析结果表明:配合物1和2的晶体都属于三斜晶系,P1空间群.配合物的中心金属离子都是六配位变形的八面体配位构型,配体4,4'-联吡啶-2,2',6,6'-四羧酸的羧基均以单齿形式配位.室温固体荧光测试结果显示配合物2具有较强的荧光.     

Synthesis of 2′,3′-Dideoxy-2′-Fluorokanamycin A

2′,3′-Dideoxy-2′-fluorokanamycin A (23) was prepared by condensation of 6-azido-4-0-benzoyl-2,3,6-trideoxy-2-fluoro-α-D-ribo-hexopyranosyl bromide (13) and a protected disaccharide (19). Methyl 4,6-0-benzylidene-3-deoxy-β-D-arabino-hexopyranoside (5) prepared from methyl 4,6-0-benzylidene-3-chloro-3-deoxy-β-D-allo-hexopyranoside (1) by oxidation with pyridinium chlorochromate followed by reduction with Na₂ S₂O₄ was fluorinated with the DAST reagent to give methyl 4,6-O-benzylidene-2,3-dideoxy-2-fluoro-β-D-ribo-hexopyranoside (7). Successive treatment of 7 with NBS, NaN₃ and SOBr₂ gave 13. The structure of the final product (23) was determined by the ¹H and ¹⁹F and shift-correlated 2D NMR spectra.     

Chiral enrichment of 2-amino-2′-hydroxy-1,1′-binaphthyl

A new synthetic procedure for the formation of 2-amino-2′-hydroxy-1,1′-binaphthyl, and a new purification procedure through the formation of Schiff bases, purification of the Schiff bases, and breakdown of the Schiff bases through amine exchange, are described. Through the new purification procedure, greater than 99% purity of the compound can be obtained easily and reliably. A set of procedures were examined to compare the efficiency and reliability to resolve 2-amino-2′-hydroxy-1,1′-binaphthyl into enantiomers. A new procedure was discovered to enrich enantiomeric excess from less than 10% to 95–99% in one step. Even a racemic mixture from an achiral procedure can be enriched to 67% e.e. in about 4% yield. The X-ray crystal structure of the racemic mixture [rhombohedral, space group Iba2, a=15.718(2) Å, b=21.703(2) Å, c=8.5398(9) Å, V=2913.2(5) ų, R1=0.0705, Z=8, d_calcd=1.301 g/cm³, F(000)=1200 e] was solved to elucidate the intriguing behavior of this compound.     

Concise Synthesis and Cellular Evaluation of 3′-Formyl-4′,6′-dihydroxy-2′-methoxy-5′-methylchalcone (FMC) and Its Analogues

3′-Formyl-4′,6′-dihydroxy-2′-methoxy-5′-methylchalcone (FMC) was a natural product isolated from Cleistocalyx operculatus. A four-step synthetic strategy toward FMC and its four analogues (1b–1e) was first developed. All compounds were synthesized from commercially available 2,4,6-trihydroxyacetophenone; formylation at 3′ position under Vilsmeier–Haack conditions was followed by the introduction of a methyl group at 5′ position. The key step of selective methylation at 2′ position was achieved by trimethylsilyldiazomethane (TMSCHN₂). Then substituted aromatic aldehydes were condensed through Claisen–Schmidt reaction in the presence of potassium hydroxide. All structures were confirmed by ¹H NMR, ¹³C NMR, and high-resolution mass spectra. FMC and analogues were screened for their antiproliferative activity.