Circular dichroism of some pregnenes substitutes at C-17

The optical properties of pregnenes containing different substituents at C-17 (—SCN, —SAc, —SC(CH₃)₂O—, —Br, —OAc, —N₃) have been investigated with the help of the CD spectra. It is shown that the sign and value of the Cotton effect of the carbonyl chromophore n → π^* transition is determined by the nature of the substituent at C-17.     

Binulcear polyunsaturated organosilicon dendrimers

Binuclear polyunsaturated organosilicon dendrimers of the zero and first generations, whose central silicon atoms are linked by-CH₂-Ch₂-,-CH=CH-, or-C≡C-bridges, and also containing internal (C≡C) and (CH=CH) groups are prepared. NMR spectra of all the compounds obtained are studied. Their molecular weights were calculated and evaluated experimentally. Key parameters of new dendrimers are presented.     

Modified steroids. 102. Approach to the synthesis of steroid 16,17-aziridines and stereospecificity of the photoinduced addition of carbethoxynitrene to steroid 16-en-20-ones

Conclusions The reaction of 16-en-20-keto-steroids with carbethoxynitrene has been studied. The addition of carbethoxynitrene to the ¹⁶ bond took place exclusively at the -region of the molecule with the formation of 16,17-carbethoxyepimino-20-keto-steroids.For communication 101, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 186–191, January, 1979.     

Transformed steroids

A preparative method for 9a-hydroxylation of ⁵-3-hydroxysteroids using the fungi ofCircinella sp. 10Kh-1220 not capable of modifying theA ring has been developed. It is established that the yields of the main and the side products greatly depend on the transformation conditions, mycelium age, and the structure of the steroid substrate. Under the optimal transformation conditions novel 9-hydroxysubstituted derivatives of androstenolone, pregnenolone, 16-dehydro-16,17-epoxy-, and-16-methoxypregnenolone have been obtained in 36–80 % yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 737–743, April, 1994.     

Novel acyclic and macrocyclic highly unsaturated silahydrocarbons

Two novel silicon-containing acetylenic synthons, 1-[dimethyl(ethynyl)silyl]-2-[ethynyl(methyl)-(vinyl)silyl]ethyne and bis[(ethynyldimethylsilyl)ethynyl](methyl)vinylsilane, were obtained by the reaction of diethynyl(methyl)vinylsilane with ethylmagnesium bromide and ethynylfluorodimethylsilane. The reaction of magnesium derivatives of the products and diethynyl(methyl)vinylsilane with organylhalosilanes gave macrocyclic polyunsaturated silahydrocarbons containing numerous endo- and exocyclic miltiple bonds.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 10, 2004, pp. 1612–1616.Original Russian Text Copyright © 2004 by O. Yarosh, Zhilitskaya, N. Yarosh, Istomina, Albanov, Chuvashev, Voronkov.This revised version was published online in April 2005 with a corrected cover date.     

Discovery of cationic domino reaction under the NMR experiment conditions: diastereoselective dimerization of 2-arylmethylideneindolin-3-ones to pentacyclic 3-hydroxyindolenine system

NMR spectroscopy (1D and 2D) showed that the protonation of the capto-dative heterocyclic α-amino enones, viz., (Z)-2-arylmethylideneindolin-3-ones, with strong acids led to stable (aryl)(3-hydroxyindol-2-yl)methyl cations. These substrates in trifluoroacetic acid underwent cationic domino reaction, which resulted in polynuclear pyrido[1,2-a: 5,6-b′]-[1,2′]biindoles.     

1,4-Dichalcogenins: Synthesis from Dichloroethenes and Elemental Chalcogens in a Hydrazine Hydrate–Potassium Hydroxide System

Russian Journal of General Chemistry - A possibility of the synthesis of 1,4-dichalcogenins by the reaction of vinylidene chloride or 1,2-dichloroethene with elemental chalcogenes in a hydrazine...     

Novel Highly Unsaturated Macrocyclic and Macrobicyclic Silahydrocarbons Containing Si-H Bonds and Exocyclic Vinyl Groups

The first representative of cycloorganylhydrosilalkynes (C≡CSiHR)_n, tetramethylcyclotetrasilethyne, was prepared by organomagnesium synthesis. The same procedure was used to synthesize 15-membered polyunsaturated silahydrocarbons containing both triple and double bonds in the ring and an exocyclic vinyl group. Organomagnesium synthesis was also used for preparing previously unknown polyunsaturated macrobicyclic silahydrocarbons containing a -CH₂CH₂- bridge. The ¹H, ¹³C, and ²⁹Si NMR and IR spectra of the synthesized compounds were studied.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1157–1160.Original Russian Text Copyright © 2005 by O. Yarosh, Zhilitskaya, Istomina, N. Yarosh, Albanov, Voronkov.     

Alkaline cyclization of carboethoxyhydrazones of 21-hydroxy-20-ketosteroids to 17Β-(1′,3′,4′-oxadiazin-2′-ones) and its correlation with the geometry of the hydrazone fragment

Conclusions The basic cyclization of 21-acetoxy- and 21-hydroxy-20-carboethoxyhydrazones of 20-ketosteroids to 173-(1,3,4-oxadiazon-2-ones) proceeds only for the geometric isomer with syn configuration of the acetoxymethylene or hydroxymethylene group and the ureide group relative to the C=N bond.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 194–197, January, 1987.