6,6′-Dibromo-3,3′-dimethoxy-2,2′-dihydroxy-1,1′-biphenyl: preparation and resolution

A pratical route to prepare the title biphenyl 1 starting from 3,3′,2,2′-tetramethoxy-1,1′-biphenyl 2 is described. Resolution of 1 was achieved by its conversion into the corresponding diastereomeric menthyldicarbonate. The absolute configuration of (P)-(+)-1 was confirmed by X-ray analysis of the related diastereomer.     

Synthesis of 1′-substituted 4′,4′-dimethyl-6′-methoxy-4′H-spiro[cyclohexane-1,3′-isoquinolines]

The reaction of 1-(4-methoxyphenyl)-1-(1-methylcyclohexyl)ethanol with nitriles in concentrated sulfuric acid afforded 1′-substituted 6′-methoxy-4′,4′-dimethyl-4′H-spiro[cyclohexane-1,3′-isoquinolines] as a result of consecutive Wagner-Meerwein rearrangement and Ritter reaction.     

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.     

Die indikatoreigenschaften des vicinalen m-Xylenolphthaleins (3′ ,5′ ,3′' ,5′'-Tetramethylphenolphthalein)

Ohne ZusammenfassungMit 1 Abbildung     

2′-5′连接寡聚核苷酸——2′-5′A核的固相合成

本文用磷酸三酯法,在交联聚丙烯酰吗福啉载体上,以1,3,5-三甲苯磺酰氯(MS)加N-甲基咪唑(N-Mein)为缩合剂,合成了2′-5′相连的寡聚腺苷酸——2′-5′A核。每个保护的单体接到载体上的收率是令人满意的,分别是100％,64％和89％。在合成过程中,我们对合成一系列中间体和制备载体的方法进行了改进,使产物收率大大提高,分离操作得以简化。     

Investigations of 2,3′-biquinolines 23. Synthesis of 1′-R-1′,4′-dihydro-2,3′-biquinolin-4′-ones by Claisen condensation

A method has been developed for the synthesis of 1′-R-1′,4′-dihydro-2,3′-biquinolin-4′-ones based on the interaction of quinaldine with N-alkyl-N-formylanthranilic acid methyl esters under the conditions of the Claisen condensation. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 409–410, March 2008.     

Improved Synthesis of 4,4′-Disubstituted-2,2′-Bipyridines

Ruthenium(II) tris(2,2′-bipyridine) complexes show interesting photochemical properties^1. Complexes containing substituents in the 4-and 4′-position of the 2,2′-bipyridine ligand have recently been used in systems which are aimed at the conversion and storage of solar energy^2,3. 2,2′-Bipyridine has a long history as a metal-chelating agent⁴. The use of 4,4′-disubstituted bipyridines as metal-chelating agents so far has been restricted probably because the reported syntheses of these compounds are rather laborious and the yields are low or moderate^5–8.     

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.     

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.     

Electrochemically initiated fragmentation reaction of 9,9′-dinitro-9,9′,10,10′-tetrahydro-10,10′-bianthryl

A mechanism for the electroreduction of 9,9-dinitro-9,9,10,10tetrahydro-10,10-bianthryl in DMF, which results in the formation of anthracene and 9-nitroanthracene has been proposed on the basis of data from polarography, cyclic voltammetry, and electrolysis at a controlled potential.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1321–1325, June, 1991.     

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.     

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.

     

Calorimetric study of 2′-methylacetophenone and 4′-methylacetophenone

Values of the condensed phase standard (p = 0.1 MPa) molar enthalpy of formation for 2′- and 4′-methylacetophenones were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The values of the standard molar enthalpy of vaporization, at T = 298.15 K, were measured by Calvet microcalorimetry. Combining these two values, the following enthalpies of formation in the gas phase, at T = 298.15 K, were then derived: 2′-methylacetophenone, –(115.7 ± 2.4) kJ · mol⁻¹, and 4′-methylacetophenone, –(122.6 ± 2.4) kJ · mol⁻¹. Substituent effects are discussed in terms of stability and compared with other similar compounds. The value of the standard molar enthalpy of formation for 3′-methylacetophenone was estimated from isomerization schemes.     

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.     

Unexpected racemization behavior of 8,8′-dialkyl-1,1′-biisoquinoline

The racemization behavior of a series of atropisomeric 8,8′-dialkyl-1,1′-biisoquinolines, in which methyl, ethyl, and isopropyl groups are introduced for enhancing the transannular steric hindrance, is reported. Contrary to prior expectations, their configurational stability was inversely proportional to the steric size of the alkyl groups.     

Synthesis of β-L-2′,3′-Dideoxy-2′-fluoro-3′-hydroxymethylarabinofuranosyl Pyrimidine Nucleosides

β-2′,3′-Dideoxy-2′-fluoro-3′-hydroxymethylarabinofuranosylthymine 10 and cytosine 12 were synthesized from L-xylose and were found to be inactive against HIV-1 in acutely infected lymphocytes.     

5′-鸟嘌呤核苷三磷酸(5′-GTP)和5′-尿嘧啶核苷三磷酸(5′-UTP)二钠盐的制备

前言核苷三磷酸是含有两个高能磷酸键的高能化合物。除了参与核糖核酸合成外,在生物体内的生命活动中起着重要的作用。ATP 主要用于供给合成细胞的物质所需要的能量,也是被称为“第二信使”的环化AMP(3′5′-cyclicAMP)的前体。而后者已知与多种生化过程有关。CTP 参与重要磷脂类的合成。GTP 在蛋白质合成中是必不可少的。UTP 是肝脏中重要解毒剂尿二磷葡萄糖醛酸(UDPG)的前体,与肝糖元、酸性粘多糖的合成密切相关。根据已知的生理功能有些兄弟研究单位作了一些临床应用试验,还值得进一步探讨。