Formation of 17beta-alkoxy-16-keto steroids by reaction of 16alpha-hydroxy-17-keto and 17beta-hydroxy-16-keto steroids with trimethylsilyl iodide in the presence of alkyl alcohols

16Alpha-hydroxy-17-keto steroids, 1, 3, and 8, and their 17beta-hydroxy-16-keto isomers, 4, 5, and 9, were transformed into the corresponding 17beta-alkoxy-16-keto derivatives on treatment with trimethylsilyl iodide (TMSI) in the presence of alkyl alcohol in CHCl3 in poor to high yields.     

Transformed steroids—part 95 : High pressure induced 1,3-dipolar cycloaddition of nitronic esters to 16-dehydro-20-oxo steroids

High pressure induced cycloaddition of Z and E nitronic esters (2) to 16-dehydro-20-oxo steroids (1) leads to regiospecific formation of steroido [16α,17α-d] tetrahydro-l',2'-oxazoles (3 and 4). It is shown that both modes (“exo-endo”) of dipolarophile approach to the dipole are realized for most steroids examined. All four possible isomers are isolated and their preferred conformations are established. It is shown that conversion of unstable stereomers to stable ones (3'→ 4; 4'→ 3) proceeds as a simultaneous nitrogen inversion and isoxazolidine cycle conformational change (_NE→E^N).     

Transformed steroids Communication 152. Photocycloaddition of 1-pentyne to 16-dehydropregnenolone acetate

Conclusions The regio- and stereospecific [2 + 2]-photoaddition of 1-pentyne to 16-dehydropregnenolone acetate has been used to obtain 2-propyl-16,17-cyclobuteno- and cyclobutanoprogesterones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.5, pp. 1184–1187, May, 1986.     

Transformed steroids. 112. 17α-Fluoro-16α-amino-20-ketosteroids

Conclusions The reaction of 16,17-epiminopregnenolone 20-carbethoxyhydrazone with HF and subsequent hydrolysis leads to 17-fluoro-16-amino-20-ketosteroids.See [1] for Communication 111.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1637–1639, July, 1980.     

Transformed steroids. 181. Synthesis of 16α,17α-cyclohexano-19-norprogesterone

Oxidative functionalization of the 19-angular methyl group of pregna-D₆-pentarane with its subsequent removal gave 16,17-cyclohexano-19-norprogesterone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1636–1638, July, 1990.     

Transformed steroids 129. Synthesis of 6α-methyl-16α,17α-cyclobutanoprogesterone

Conclusions A synthesis of 6-methyl-16.17-cyclobutanopregn-4-ene-3,20-dione was carried out by opening the 5,6-oxide ring with a Grignard reagent, with preliminary protection of the 20-keto group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2151–2154, September, 1982.     

Transformed steroids. 128. Synthesis of the isomeric 16α- and 16β-lactones of 3β,16-dihydroxy-24-nor-5α-cholan-23-oic acid

The paper is devoted to the synthesis of steroids with an additional ring E consisting of a saturated lactone ring in forms isomeric at the 16-center. The basic intermediates for yielding such compounds were the products of the Reformatskii reaction with 3,16α-diacetoxypregn-5-en-20 one. The Δ²⁰⁽²²⁾-lactone was hydrogenated to the compound with a saturated lactone ring and a Δ⁵ bond and to the fully saturated product. Its epimer at the 16-center was obtained from the ethoxycarbonyl triol forming the second product of the Reformatskii reaction. The dehydration of the latter gave a mixture of 20(21)- and 20(22)-enes, the hydrogenation of which led to the 3,16-diacetate of ethyl 24-norcholanoate. Subsequent saponification, methylation, oxidation, reduction, and cyclization led to the 6-deoxy analog of chiogralactone. The absolute configurations at C(16) of the three lactones obtained were determined by the Hudson-Klyne rule and were confirmed by analysis of the CD spectra. The unambiguity of the hydrogenation of the Δ²⁰⁽²²⁾ bonds of the intermediate compounds was confirmed by the PMR spectra.     

Transformed steroids

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