Transformed steroids

Conclusions The hydration of the triple bond in 17-ethynyltestosterone, its 17-acetate, and in 17-ethynyland-rost-5-ene-3,17-diol, its 3-acetate and the 3,17-diacetate by treatment with mercuric acetate in the presence of cationite Dowex-50 (H⁺ form) was accomplished, as a result of which some 20-ketols of the 17-isopregnane series were obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 639–641, March, 1973.     

Quantitative <Superscript>2</Superscript>H NMR spectroscopy 2. “H/D-Isotope portraits” of cyclic monoterpenes and discrimination of their biosynthetic pathways

Site-specific deuterium distribution in molecules of the representative series of natural monoterpenes was studied by quantitative ²H NMR spectroscopy. “H/D-isotope portraits” of these compounds have general characteristic features reflecting biosynthetic pathways. The data obtained suggest that monoterpenes in plants are formed through 1-deoxy-D-xylulose-5-phosphate (DXP pathway) rather than by the classical mevalonate scheme. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1222–1228, May, 2005.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 4. New polydentate azomethine ligands based on 2,5-diformylpyrrole and 2,6-diformylpyridine

The reactions of 2,5-diformylpyrrole (1) and 2,6-diformylpyridine (2) with propane-1,3-diamine afforded new macrocyclic Schiff"s bases 5 and 6, respectively. Their structures were established by NMR spectroscopy and mass spectrometry. Binuclear copper(ii) and nickel(ii) complexes with ligand 5 were synthesized. Pentadentate Schiff"s base, viz., 2,6-bis[(2-aminophenylimino)methyl]pyridine, was prepared by demetallation of its complex with Cd(ClO₄)₂ using Na₂S. In solutions, the latter Schiff"s base is quantitatively transformed into 2,6-bis(benzoimidazolyl)pyridine under the action of atmospheric oxygen or other mild oxidizing agents.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 3. New polydentate macrocyclic ligands in reactions of 4-alkyl-2,6-diformylphenols with 1,2-diaminobenzenes

The mechanism of abnormal condensation of 2,6-diformyl-4-R-phenols with 1,2-diaminobenzenes accompanied by the reduction of two of four double C=N bonds in macrocyclic Schiff"s bases formed was studied by DFT (gradient-corrected PBE functional, TZ2p basis set). In the first step, [1+1] Schiff"s base is formed and disproportionates further to afford amine and benzoimidazolylphenols. Two new macrocyclic polydentate ligands containing two CH₂—NH moieties in the rings were synthesized. The reduction of one of these ligands with sodium borohydride gave the new macrocyclic ligand, whose structure and conformations were studied by the DFT method.     

Electron-transfer induced haptotropic isomerization of fluorenylmanganesetricarbonyl complexes: electrocatalytic and chain mechanisms

The electrochemical reduction of (⁶-C₁₃H₉)Mn(CO)₃ (1, where C₁₃H₉—fluorenyl) has been studied in THF by cyclic voltammetry and preparative controlled potential electrolysis. One-electron reduction of1 to the corresponding 19-electron radical anion1 ^.– is accompanied by the haptotropic isomerization of the latter to the radical anion (⁵-C₁₃H₉)Mn(CO)₃ ^.– (2 ^.–), which is oxidized at the electrode to neutral complex2. Electron-transfer induced isomerization1 2 is an electrocatalytic process with current efficiency of 600%, which can be also promoted by catalytic amounts (20%) of the chemical reducing agents (benzophenone radical anion or sodium amalgam). If the reaction is chemically induced, the radical anion2 ^.– is oxidized by initial complex1; as a result the electron-transfer induced isomerization1 2 proceeds by a chain mechanism. The influence of the electronic state (18e^–/19e^–) of ⁶- and ⁵-fluorenyl complexes on the position of the equilibrium of the intra-ring haptotropic isomerization reaction is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1805–1809, October, 1994.This work was supported in part by the Russian Foundation for Basic Research (Project No. 93-03-05209) and the International Science Foundation (Grant No. REV 000).     

Reaction of 8-(dimethylamino)methyl-1-naphthyl phenyl silanethione with phosphorus ylides

The title silanethione reacts with phosphorus ylides under conditions of kinetic control to give betaines containing a linear fragment. Under conditions of thermodynamic control, the derivatives of phosphonium 1-silaacenaphthene-1-thiolate are formed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2140–2141, December, 1993.     

Quantitative 2H NMR spectroscopy. 1. Thermodynamic H/D isotope effects in N,N-dimethylformamide and cyclopentadiene molecules

A new method for quantification of the relative distribution of deuterium in molecules is proposed. The technique is based on the lineshape analysis in the ²H NMR spectra obtained at the natural abundance level of deuterium with allowance for inhomogeneity of the magnetic field. The equilibrium thermodynamic H/D isotope effects for hindered rotation about the C—N bond in the N,N-dimethylformamide molecule and for prototropic exchange in the cyclopentadiene molecule were determined. The results obtained agree with those of DFT calculations of the vibrational energies.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 5. Novel complexes of asymmetric polydentate macrocyclic Schiff bases. Step-by-step synthesis

Reactions of 2,6-bis(3-aminopropylaminocarbonyl)pyridine (1) with 4-tert-butyl-2,6-diformylphenol and 2,5-diformylpyrrole in the presence of Ba(ClO₄)₂ in EtOH afford barium complexes with asymmetric macrocyclic Schiff bases as soft and hard ligands. The reaction of compound 1 with Cu(OCOCMe₃)₂ involves closure of a tetrahydropyrimidine ring to give a mononuclear complex, which was structurally characterized by X-ray diffraction analysis.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands 7. Directed step-by-step synthesis of novel unsymmetric macrocyclic ligands

Novel asymmetric macrocyclic Schiff bases were synthesized by the condensation of N,N′-bis(2-aminophenyl)-3,4-diphenylthiophene-2,5-dicarboxamide (1) with diformyl derivatives of phenol, furan, difurans, pyridine, pyrrole, and dipyrroles. The reaction proceeds in high yields and without by-products in methanol in the presence of inorganic and organic acids (proton-template condensation). In the case of monocyclic diformyl derivatives and di(5-formylfuran-2-yl) sulfide, the reaction occurs in 1,4-dioxane (templateless synthesis). The synthesized macrocycles were characterized by elemental analysis data and NMR and mass spectra. For Part 6, see Ref. 1. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2152–2156, September, 2005.