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.     

A new procedure for the synthesis of arylor hetaryl-substituted conjugated diynes

On treatment with two equivalents of NaNH₂ in liquid ammonia the enyne sulfides RCC–CH=CHSEt (cis-isomers, where R is an aryl or a hetaryl) afford sodium salts of 1,3-diynes. The latter react with ethyl bromide to produce disubstituted diynes RCC–CCEt in high yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 348–350, February, 1993.     

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.     

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 cis-hydroazulenes

A 2-substituted dihydrotropone is converted into a cis-hydroazulene intermediate via a novel Lewis acid catalyzed olefin cyclization.     

A new approach to the synthesis of 3,4-dihydroisocoumarin derivatives

A new, simple, one-step synthesis of 3-substituted 3,4-dihydroisocoumarins is developed. The products are obtained by the reaction of o-methoxycarbonyl arenediazonium bromides with unsaturated compounds in the presence of CuBr as a catalyst.     

A new approach for the synthesis of K-free nickel hexacyanoferrate

A Ni, Al hydrotalcite-like compound (Htlc) has been proven an useful host material for an alternative synthesis of a K⁺-free mixed hexacyanoferrate Ni_1.5Fe^III(CN)₆, which is very difficult to obtain in bulk. The first stage of the procedure consists in the intercalation of hexacyanoferrate(III) inside the Htlc structure. The intercalated Htlc has been treated with a NiNO₃ solution. The obtained material has been characterized by XRD, XAS Raman and FT-IR spectroscopy. The voltammetric response of the compound obtained after the complete solubilization of the Htlc host shows a typical fingerprint of nickel hexacyanoferrate material with a very low level of potassium. Elemental analysis confirmed the absence of K⁺ and thus the occurrence of K⁺-free nickel hexacyanoferrate (14% yield).     

A new approach to the synthesis of ‘chiral’ glycine

The stereospecific coordination of N-benzylglycinate ion in ΔR-(N-benzylglycinato)bis(ethylene-diamine) cobalt(III) chloride has been determined by X-ray crystallographic analysis, rotatory dispersion and ¹H NMR spectroscopy. The chiral glycinato-N and Co centres influence the relative rates of exchange of the diastereotopic glycine methylene protons in basic solution (pH 10·5 with Na₃PO₄inD₂O) and a synthesis supposedly of S-(N-benzyl)- 2-²H glycinate ion ≈ 80% optical purity) has been achieved.     

A new approach to the synthesis of lysophosphatidylcholines and related derivatives

A new stereospecific synthesis of lysophosphatidylcholines is reported. The sequence relies on orthogonal protection of hydroxyl groups derived from glyceric acid, using fluorenylmethylcarbonate versus tetrahydropyranyl ether functions, that allow regiospecific introduction of substituents to obtain the target phospholipid compound.     

Nitrodestannylation. A new synthesis of conjugated nitro cyclo olefins

A new process for the conversion of cyclic ketones to 1-nitro olefins, as outlined below, is described.     

A new approach to isoindoloisoquinolinones. A simple synthesis of nuevamine

A convenient and versatile short step synthesis of isoindoloisoquinolinones, illustrated by the total synthesis of the alkaloid nuevamine 1a, is described. The tetracyclic lactam compounds were obtained by a tactical combination of the Parham procedure for the elaboration of the isoindolinone template and an aryne-mediated cyclization giving rise to the nitrogen containing six-membered heteroring unit.