Electrospray ionization tandem mass spectrometry determined regioisomeric structures of disubstituted beta-cyclodextrin derivatives

Electrospray ionization tandem mass spectrometry was applied to the analysis of regiospecifically disubstituted beta-cyclodextrins. Each disubstituted regioisomer showed unique fragmentation, distinguishing each of them unambiguously. These results demonstrate that mass spectrometry is the most straightforward method among those reported in the assignment of regioisomeric structures of these oligosaccharides.     

Bromination of unsymmetrical cross-conjugated dienones of cyclohexane series. Synthesis of regioisomeric dibromo adducts

Russian Journal of General Chemistry -     

Stabilisation of human telomeric quadruplex DNA and inhibition of telomerase by a platinum-phenanthroline complex

Two new mono-substituted phenanthroline ligands and their platinum(II) square planar complexes have been prepared; one of the complexes has been shown to induce a high degree of quadruplex DNA stabilisation and to inhibit telomerase.     

Synthesis of regioisomeric analogues of crisamicin A

The synthesis of bis-furonaphthopyrans 12a and 12b, regioisomeric analogues of the dimeric pyranonaphthoquinone antibiotic crisamicin A 1 is described. The key intermediate 16 was prepared via a one-pot in situ Suzuki-Miyaura homocoupling of naphthyl triflate 23 using bis(pinacolato)diboron. Oxidation of binaphthyl 16 to bis-naphthoquinone 14 was then effected with silver(II) oxide and nitric acid. Efficient double furofuran annulation of bis-naphthoquinone 14 with 2-trimethylsilyloxyfuran 8 afforded bis-furonaphthofuran adducts 13a and 13b as an inseparable 1:1 mixture of diastereomers. Oxidative rearrangement of this mixture of bis-furonaphthofuran adducts 13a and 13b using silver(II) oxide and nitric acid afforded unstable bis-furonaphthopyrans 12a and 12b also as a 1:1 mixture of diastereomers. Addition of 2-trimethylsilyloxyfuran 8 to naphthoquinone 25 afforded adduct 26 that underwent oxidative rearrangement to furonaphthopyran 27, however attempts to effect Suzuki-Miyaura homocoupling of triflates 26 and 27 to their respective dimers 13 and 12, was unsuccessful.     

Synthesis of two novel regioisomeric oxospiropyrazole piperidine scaffolds

The synthesis of two unprecedented regioisomeric oxospiropyrazole piperidine scaffolds is detailed. Their potential utility as templates for drug discovery is also exemplified. Chemical stability and solid state conformation were also evaluated.     

Cellular delivery of peptide nucleic acids and inhibition of human telomerase.

BACKGROUND: Human telomerase has an essential RNA component and is an ideal target for developing rules correlating oligonucleotide chemistry with disruption of biological function. Similarly, peptide nucleic acids (PNAs), DNA analogs that bind complementary sequences with high affinity, are outstanding candidates for inducing phenotypic changes through hybridization. RESULTS: We identify PNAs directed to nontemplate regions of the telomerase RNA that can overcome RNA secondary structure and inhibit telomerase by intercepting the RNA component prior to holoenzyme assembly. Relative potencies of inhibition delineate putative structural domains. We describe a novel protocol for introducing PNAs into eukaryotic cells and report efficient inhibition of cellular telomerase by PNAs. CONCLUSIONS: PNAs directed to nontemplate regions are a new class of telomerase inhibitor and may contribute to the development of novel antiproliferative agents. The dependence of inhibition by nontemplate-directed PNAs on target sequence suggests that PNAs have great potential for mapping nucleic acid structure and predictably regulating biological processes. Our simple method for introducing PNAs into cells will not only be useful for probing the complex biology surrounding telomere length maintenance but can be broadly applied for controlling gene expression and functional genomics.     

Synthesis and chemical transformations of mono- and disubstituted cyanamides

The review briefly discusses the known methods for the preparation of substituted cyanamides, their typical transformations, and some aspects of practical applications of these compounds in medicine, various branches of industry, and agriculture.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1439–1454.Original Russian Text Copyright © 2004 by Nekrasov.Dedicated to the memory of Prof. Yu.S. Andreichikov     

Synthesis of some halogenated and disubstituted amino benzylacyclouridine derivatives

1′-Halogenomethyl, 1′-azidomethyl and 1′-disubstituted aminomethyl derivatives of BAU (5-benzylacyclouridine) and BBAU (5-benzyloxybenzylacyclouridine) were synthesized in the course of our studies of benzylacyclouridines. Two new and more convenient preparations of the previously known aminomethyl-and hydroxymethyl-parent compounds of these two series, AM-BAU, AM-BBAU and HM-BBAU are also reported. These compounds were synthesized during a search for potential antiviral agents and pyrimidine phosphorylase inhibitors.     

含三嗪基二取代氨基甲酰脲的合成及其生物活性

取代脲类化合物具有多种特异的生物活性,诸如除草、杀虫、抗菌、植物生长调节活性[1~2]等,对该类化合物的合成及生物活性研究成为农药开发的热点,探索新的取代脲类化合物一直是许多化学工作者关注的课题[3~5]。目前,取代脲类化合物研究主要集中在脲桥上取代基的变化[4~5]和取代硫脲的活性[6~8]等方面,而对脲桥结构的改变或拓展研究鲜见报道。氨基甲酰脲是一类特殊的脲衍生物,具有明显的生物活性[9],以其为前体,合成具有氨基甲酰脲基本结构的化合物,改变脲桥结构或扩大取代脲研究范畴,从而探索新的有价值的农药或药物前体。三嗪基是多种除草…     

Synthesis of regioisomeric N- and O-alkylated 3-polyfluoroalkyl-1,2-dihydroquinoxalin-2-ones

3-Polyfluoroalkyl-1,2-dihydroquinoxalin-2-ones react with 4-bromobutyl acetate to furnish 1-(4-acetoxybutyl)quinoxalin-2-ones and 2-(4-acetoxybutoxy)quinoxalines in the ratio 2: 1. Deacylation of these compounds under acidic conditions gives the corresponding 1-(4-hydroxybutyl)- and 2-(4-hydroxybutoxy)-substituted quinoxalines. The structures of compounds synthesized were established by X-ray crystallography, IR spectroscopy, ¹H and ¹⁹F NMR spectroscopy, GLC-MS.     

Synthesis of a regioisomeric analogue of the 3C-protease inhibitor thysanone via a Hauser annulation strategy

Hauser annulation of 3-cyano-5,7-dimethoxy-(3H)-isobenzofuran-1-one 4 with ethyl acrylate as a method to access activated naphthoquinone 3, a key intermediate for the synthesis of thysanone 1, proved unreliable. In contrast to this, Hauser annulation of regioisomeric 3-cyano-4,6-dimethoxy-(3H)-isobenzofuran-1-one 13 with ethyl acrylate proceeded readily affording ethyl 5,7-dimethoxy-1,4-naphthoquinone 12, after oxidation of the initial dihydroxynaphthalene 16. Allylation of naphthoquinone 12 followed by reductive methylation and Wacker oxidation afforded ketone 11 that underwent CBS reduction to (2′S)-alcohol 19 followed by cyclisation to lactone 20. Reduction of the lactone followed by oxidative demethylation afforded (1S,3S)-6,8-dimethoxy-1-hydroxy-3-methylpyrano[2,3-c]-1,4-naphthoquinone 22, a regioisomeric analogue of the 3C-protease inhibitor thysanone 1.     

手性方酰化双取代哒嗪的合成及荧光性研究

哒嗪衍生物是一类重要的芳香杂环化合物,哒嗪环常出现于农药、医药等具有生物活性的化合物中,研究哒嗪化合物的结构和性能的关系具有重要的科学意义和潜在的应用价值.作为中心桥联基的有机液晶化合物我们已有过系列报道[1-4].     

Synthesis of mono- and disubstituted tetra(tert-butyl)porphyrazines

Bromination of tetra(tert-butyl)porphyrazine by N-bromosuccinimide in chloroform results in the formation of mono- and dibromides, substitution for the bromine atoms of which produced the corresponding cyano, phenoxy, phenylthio, styryl, phenylethynyl and piperidino derivatives. From the monobromide and 2,2-bis(p-hydroxyphenyl)propane, the dimeric porphyrazine 2,2-bis[p-tetra(tert-butyl)porphyrazyloxyphenyl]propane was similarly obtained.Scientific Research Institute of Organic Intermediate Products and Dyes, Moscow 103787. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1206–1212, September, 1994. Original article submitted September 6, 1994.     

Synthesis and atropisomerism of 2,2′-ortho disubstituted biphenyls

The role of substitution on the aromatic rings for the synthesis of 2:2 disubstituted biphenyls has been investigated. Atropisomerism involved in the above ring system has been studied using NMR spectroscopy. The outcome of inter and intramolecular Heck reaction is discussed.     

哌嗪含磷双取代衍生物的合成及结构表征

以无水哌嗪为原料,合成了9个1,4-位分别带有磷酰化氨基酸和缩氨基硫脲取代基团的哌嗪衍生物,通过1 H NMR、13C NMR、31 P NMR、IR、MS对其结构进行表征.并通过ESI-MS研究目标化合物与细胞色素的弱相互作用,初步评价了他们的生物活性.     

Synthesis and characterization of a new disubstituted polyacetylene containing indolylazo moieties in side chains

A new disubstituted polyacetylene with indolylazo moieties in its side chains ( 9 ) was synthesized by a post functionalization strategy, which was difficult, or perhaps impossible, to obtain from the direct polymerization of its corresponding monomer. The polymer is soluble in common solvents and thermally stable. The polymer shows good optical transparency with an absorption maximum at 393 nm and a band edge at ～530 nm. Its poled film exhibits a resonant d₃₃ value of 17.9 pm/V and its optical nonlinearity is resistant to thermal decay at up to 147 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5672–5681, 2006     

Synthesis and thermal analysis of disubstituted propiolates bearing terphenylene mesogen

Novel disubstituted propiolates bearing chromophoric terphenylene mesogenic groups, namely, 4′-cyano-4-terphenylyl-2-octynate M(CN) and 4′-methoxyl-4-terphenylyl-2-octynate M(OCH₃) are synthesized, where the terphenyl groups are connected to the C≡C through ester linkage directly. Using transition-metal catalysts such as the classical MoCl₅- and WCl₆-based metathesis catalysts, the polymerization of the M(CN) and M(OCH₃) are carried out in a series of different solution, however, did not obtain any products. It suggests that the WCl₆- and MoCl₅-based catalysts are poisoned by the polar groups, on the other hand, the bulk terphenyl groups and the long alkyl chain around the C≡C bond might inhibit the reaction. M(CN) displays monotropic nematicity, whereas M(OCH₃) exhibits enantiotropic nematicity and smecticity (SmA_d) with a bilayer arrangement when cooled and heated. Ultraviolet spectroscopy and photoluminescence measurements also show that the terphenyl groups endow disubstituted propiolates with strong UV light absorption and high photoluminescence.