A new approach to the synthesis of 16-heteroprostanoids via isoxazole intermediates

Translated from Khimiya Geterotsiklicheskikh Soedinenii. Vol. 30. No. 3, pp. 424–425, March, 1994.     

Locked and unlocked nucleosides in functional nucleic acids

Nucleic acids are able to adopt a plethora of structures, many of which are of interest in therapeutics, bio- or nanotechnology. However, structural and biochemical stability is a major concern which has been addressed by incorporating a range of modifications and nucleoside derivatives. This review summarizes the use of locked nucleic acid (LNA) and un-locked nucleic acid (UNA) monomers in functional nucleic acids such as aptamers, ribozymes, and DNAzymes.     

Interaction of bis-aryl functionalized molecules with nucleosides and nucleic acids

A series of novel molecules with a cyclen(1,4,7,10-tetraazacyclododecane) moiety appended on and bearing different aromatic fragments in the structures were synthesized and characterized.The binding activities of these compounds towards DNA were systematically studied by spectroscopic,viscometric and gel electrophoresis methods.The results suggest that the stacking interaction plays an important role in improving the DNA binding ability of the compounds.The binding modes of the compounds towards DNA are als...     

Solid phase synthesis of nonadecathymidylic acid by the phosphotriester approach

Nonadecathymidylic acid was synthesized by the block coupling phosphotriester approach on a polymer support.     

Pyrophosphate tetraester intermediate of coupling reactions in the phosphotriester approach to the synthesis of deoxyligoribonucleotides

The intermediate in phosphotriester formation in the presence of ARSO₂Cl, ArSO₂Tet, ArSO₂NT and mixtures of ArSO₂Cl + Tet (Nt, MeIm, DMAP) was established to be pyrophosphate tetraester II.     

A new approach to the synthesis of telluranthene

A series of new methods of synthesizing telluranthrene are proposed, based on the use of poly(o-phenylene)ditelluride and its precursors. The best yields of telluranthene are obtained by the reactions of the disodium salt of o-ditellurolobenzene with o-diiodobenzene (50–62%) and of poly(o-phenylene)ditelluride with butyllithium.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1424–1427, October, 1991.     

An olefin cross-metathesis approach to vinylphosphonate-linked nucleic acids

[reaction: see text]. The synthesis of vinylphosphonate-linked nucleotide dimers has been achieved using an olefin cross-metathesis (CM) reaction as a key step. The 1,3-dimesityl-4,5-dihydroimidazol-2-ylidine-containing catalyst 5 (Grubbs' second-generation catalyst) was found to be the superior catalyst for this transformation. Both metathesis partners were readily available using known methodology, and the vinylphosphonate-linked dimer was produced with high levels of (E)-selectivity (>20:1) in 58% yield (70% based on recovered starting material).     

A new approach to the chemical synthesis of keto-proteins

To increase the versatility of protein-conjugation, an orthogonal protection strategy is described, which enables the efficient synthesis of keto-proteins bearing a reactive ketone functionality using Boc, Fmoc, and chemical ligation methodologies. A 1,3-dithiolane group was used to protect the ketone function of levulinate- and pyruvate-derivatized peptides during solid-phase synthesis, acidolytic cleavage, and purification. When required, the 1,3-dithiolane group could be cleanly removed using aqueous silver or mercuric solutions to regenerate the reactive keto-protein at ambient temperature. The liberated keto-protein was chemoselectively conjugated in situ to an aminooxy-derivatized monodisperse polymer.     

A new approach to the synthesis of polycyclic structures

A general, convergent approach to the synthesis of polycyclic structures has been developed, based on the tandem radical addition/cyclisation of xanthates to dienones followed by an ionic ring closure to give, finally, a number of variously substituted tricyclic compounds.     

A new approach to the synthesis of fluorinated chromones

The condensation of two molecules of ethyl pentafluorobenzoylacetate gives 1-oxo-3-penta fluorophenyl-1H-pyrano[4,3-b]6,7,8,9-tetrafluorochromone.Department of Fine Organic Synthesis, Institute of Organic Chemistry, Urals Branch, Russian Academy of Sciences, 620219 Ekaterinburg. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2186–2188, September, 1992.     

An approach to the synthesis of pseudomonic acids

The synthesis of the cis-fused γ-lactone 2,7-dioxabicyclo-[4,3,0]non-4-en-8-one (3) by two routes is reported. Its stereoselective conversion to a key intermediate for pseudomonic acid synthesis is described.