Wagner-Meerwein rearrangement of steviol 16α,17- and 15α,16-epoxides

16α,17- and 15α,16-Epoxy derivatives of diterpenoid steviol having ent-kaurane structure were found for the first time to undergo Wagner-Meerwein rearrangement in alkaline medium or by the action of boron trifluoride-diethyl ether complex to give products with ent-beyerane structure. The geometric parameters of steviol 16α,17- and 15α,16-epoxides were determined by X-ray analysis.     

Density and viscosity of 16α,17α-epoxyprogesterone solutions in chloroform

density and viscosity of 16α,17α-epoxyprogesterone solutions in chloroform were determined over the concentration range up to ∼1.9 mol l⁻¹ at temperatures from 287.65 to 321.15 K. The relative viscosity data were correlated using the extended Jones-Dole equation, a good accuracy of the correlation being obtained.     

Transformed steroids. 185. Use of the Nicholas reaction for regio- and stereo-selective transformation of 16α,17a-epoxy-17Β-ethynyl-androstanes into 16α,17α-cis-disubstituted steroids

The HBF₄·Et₂O-catalyzed methanolysis reactions of the 16, 17-oxides of 17-ethy-nylandrost-4-en-3-one and its dicobalt hexacarbonyl complex were studied. It was shown that these reactions proceed with the same regiodirectivity of the oxide ring opening at the tertiary center but with a different mode of stabilization of the intermediates formed. The reaction of the free oxide proceeds without the inclusion of the external nucleophile and is concluded by the Wagner-Meerwein rearrangement; the C¹⁷-carbocation formed in the Co-coordinated oxide is stabilized by the addition of the methoxide ion and the elimination of a proton or of water. The opening of the oxide ring of dicobalt tetracarbonyl 16, 17-epoxy-17-ethynylandrost-4-en-3-one can be realized with decomplexation accompanied by carbonylation and heterocyclization.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp.1180–1184, May, 1991.     

Synthesis of 5α, 13α, 14α-Androstan-16-One and 5α, 13β, 14β—Androstan-16-One Using a Novel 17–16 Carbonyl Transposition

In the course of current work on the conformational analysis of cis-hydrindanones¹, we required 5α, 13α, 14α and 5α, 13β, 14β-androstan-16-one 5 and 10 the C and D rings of which provide rigid models of the two conformations of cis-hydrindan-2-one.     

Reaction of 5β,6β-epoxy-16α,17α-cyclohexapregnane with methylmagnesium iodide

On treatment with methylmagnesium iodide, 3β-acetoxy-5β,6β-epoxy-16α,17α-cyclo-hexapregnan-20-one undergoes 3-O-deacetylation along with the opening of the 5β,6β-epoxide ring to form 5α-methyl-6β-hydroxy steroid and the 6α-methyl-6β-hydroxy isomer, the 20-keto group remaining intact.     

Bismuth(III) triflate-catalyzed rearrangement of 16α,17α-epoxy-20-oxosteroids. Synthesis and structural elucidation of new 16α-substituted 17α-alkyl-17β-methyl-Δ-18-norsteroids

The use of bismuth(III) triflate for the rearrangement of 16α,17α-epoxy-20-oxosteroids is reported. The reactions occur under truly catalytic conditions to afford novel 17α-alkyl-17β-methyl-Δ¹³-18-nor products bearing different O-containing substituents at C16. When the reaction is performed in the absence of acylation agent a mixture of isomeric 16α- and 16β-hydroxy derivatives is obtained, whereas when carried out in the presence of such reagents, the reaction selectively affords the corresponding 16α-acyl rearranged products. The chemoselective rearrangement of 5β,6β;16α,17α-diepoxy-20-oxopregnan-3β-yl acetate to afford a ‘backbone’ rearranged product bearing the 16α,17α-epoxide group is also reported. Some mechanistic considerations are provided. All rearranged products were the subject of comprehensive structural elucidation, by the use of X-ray crystallography and 2D NMR.     

Regioselective Decomposition of 11-Substituted-16α,17α- methyleneazopregna-1,4-dien-3,20-dione

16α, 17α-Methylenepregnanes are not only the important chemical intermediates but also the excellent pharmaceutical candidates1. In order to study the structural relationship of D-ring of corticosteroid to the antiinflammative activity, 11-substituted-1…     

Transformation of 5α-H-pregn-16-en-3β-ol-20-one into pregn-4-ene-9α,16α,17α-triol-3,20-dione 16,17-acetonide

A preparative method was proposed for the preparation of pregn-4-ene-9,16,17-triol-3,20-dione 16,17-acetonide (2) from 5-H-pregn-16-en-3-ol-20-one (1). The key stage in the proposed sequence of the reactions is the microbiological 9-hydroxylation and introduction of the 4-en-3-one grouping into the molecule of1 by R- and S-dissociative forms of the Rhodococcus sp. strain.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1898–1901, August, 1992.     

The structure of 16, 17β-epoxy-17α-pregn-5-en-3β-ol-20-one monohydrate

The structure of the title compound (1) has been studied by means of X-ray diffraction. The region of cycleD in epoxide1 was compared with that of the 16,17-epoxy derivatives of progesterone and pregnenolone (studied previously) as well as with that of the respective 16,17- and 16,17-cyclopropano analogs. In contrast to the 16,17-epoxy-20-oxo derivatives, in compound1 the electron conjugation of the epoxide ring with the CH₃CO group at C(17) is partly disrupted. Moreover, the steric congestion at C(17) is significantly less pronounced in 16,17-epoxide1 than in its 16,17-counterpart. Both of these factors, especially steric decongestion, are favorable for nucleophilic attack at C(17) in the molecule of1. The X-ray diffraction data do not contradict the previously advanced mechanism of epoxide ring opening in 16,17- and 16,17-epoxy-20-oxo steroids by nucleophilic reagents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 401–405, February, 1993.     

Synthesis and transformations of the 20-substituted derivatives of 16α,17α-epoxy-5α-pregnane-3Β,21-diol-20-ones

A new and more effective sequence of reactions is proposed for the production of 16,17-isopropylidenedioxy-5-pregnane-3,21-diol-20-one. It uses methods previously unused for 5-H-steroids and involves 21-hydroxylation of 16,17-epoxy-5-pregnan-3-ol-20-one with diacetoxyiodobenzene and cis-opening of the obtained 21-hydroxy-16,17-epoxy-5-pregnane-3,21-diol-20-one by acetic acid in the presence of epoxycarbonylhydrazine, followed by condensation of the obtained product with acetone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1185–1188, May, 1991.     

Synthesis of 4-hetero-16α,17α-cyclohexanopregnanes and evaluation of their cytotoxicity against the HeLa cell line

Russian Chemical Bulletin - The oxidation of the ring A of 16α,17α-cyclohexanoprogesterone gave 5-oxo-A-nor-3,5-secopregnan-3-oic acid. The subsequent ring A closure in the latter...     

11α-羟基-17, 17α-环氧黄体酮的间接电解氧化

本文研究了以Ag^+/Ag^26+及Gr^3^+/Cr~2O~7^+为双媒质, 对甾体药物中间体, 11α-羟基-16,17α-环氧黄体酮进行双媒介电解氧化, 产物为11-酮基-16,17α-环氧黄体酮。其化学收率>95%, 电流效率达到70%以上。说法与用铬酐在醋酸中进行氧化的化学法比较, 既大大降低原料的单耗, 又可消除Gr^3^+对环境的污染。本文还探讨双媒介电解氧化的机理。     

Synthesis and Transformations of 20-Isoxazolylsteroids with Modified D Ring: I. Synthesis of 16α,17α-Epoxyderivatives

Synthesis of 16,17-epoxy-20-isoxazolylsteroids was carried out starting with dehydropregnenolone acetate. Transformation procedures for preparation therefrom of open-chain compounds were considered. Physico-chemical characteristics of compounds synthesized were investigated.     

甾体化合物 ⅩLⅤ.新法合成16α,17α-異丙叉二氧基黄体酮

应用从化合物(Ⅱ)易得的16α-羟基化合物(Ⅲ)或其乙酸酯(Ⅳ)作原料,经羟基化(Ⅴ),丙酮缩合物的形成(Ⅶ)及氧化(Ⅷ及Ⅸ)等四步,即得目的物Ⅸ。     

Practical synthesis of 16α-bromo-17α-hydroxysteroids via a Raney Ni-catalyzed bromide exchange reaction

D-ring modified glucocorticoids are attractive synthetic targets owing to their broad application in medicinal chemistry. Herein, we reported a practical synthesis of 16α-bromo-17α-hydroxysteroids from easily available 16β-bromo isomers via a Raney Ni-catalyzed bromide exchange reaction. The catalytic Finkelstein-type reaction features high yield, mild reaction condition, short reaction time and simple operation. The method provided an efficient approach to prepare 17α-hydroxy-15-pregnen-20-ones.     

Über die Darstellung von 3β, 16α-und 3β, 16β-Diacetoxy-5α-pregnan-20-on

Zusammenfassung Die Synthese von 3, 16-Diacetoxy-5 -pregnan-20-on (VI) aus 3-Acetoxy-5 -pregn-16-en-20-on und eine verbesserte Darstellung von 3, 16-Diacetoxy-5 -pregnan-20-on (III) aus 3-Acetoxy-pregna-5, 16-dien-20-on werden beschrieben.