A. A. Korobov

13C NMR spectra of 17-substituted epimeric 17? and 17?-ethynylandrostenes and their hexacarbonyldicobalt complexes

Abstract13C NMR spectra of epimeric 17α-R-substituted 17β-ethynylandrostenes (R = H, OH, OAc, OMe, NCS) and 17β-R-substituted 17α-ethynylandrostenes (R = H, OH, OAc, OMe), and their hexacarbonyldicobalt complexes, as well as of Δ16-17-ethynylandrostenes and their hexacarbonyldicobalt complexes have been studied. Stereochemical dependence of C(12), C(14), C(18), C(20) and C(21) chemical shifts on the configuration of the substituents at C(17) has been demonstrated. The effect of Co-complexation on the spectral characteristics of Co-coordinated 17-ethynylandrostenes in both Stereochemical series has been investigated.

Transformed steroids Communication 151. Mechanism of the condensation of Δ16-20-ketosteroids with S.S-diphenylsulfilimine

ConclusionsTaking 16-dehydrocorticosterone 16-acetate as am example, a new mode of stabilization of the intermediate products of addition of S,S-diphenylsulfilimine to 21-acetoxy-Δ16-20-ketosteroids has been observed, the steroidal S → M ylide (21-acetoxy-16α-S,S-diphenylsulfiliminopregn-4-en-11β,21-diol-3,20-dione) being formed.

Transformed steroids. 189. Synthesis and transformations of 21-hydroxy-5α-H-pregnane 2′,2′-dimethyl-[16α,17α-d]-thioxalanes

In a continuation of the research on use of 20-keto-16α,17α-epoxysteroid 20-hydrazones for synthesis of 17-thio analogs of 20-ketosteroid 16α,17α-acetonides [2, 3], we synthesized 5α-H-pregnane-3β,16α,21-trihydroxy-17α-thiol-20-one 16,17-acetonide and found methods for its microbiological dehydrogenation and hydroxylation into Δ4-3-keto-and 9α-hydroxy-Δ4-3-keto derivatives.

Transformed steroids. 193. Synthesis of 16α,17α-isopropylidene derivatives of pregn-4-ene-9α,16α,17α,21-tetraol-3,20-dione and its 17α-thioanalog

A study was carried out on the pathways for the transformation of 16α,17α-epoxypregn-4-ene-9α,21-diol-3,20-dione to give 16α,17α-isopropylidene derivatives of pregn-4-ene-9α,16α,17α,21-tetraol-3,20-dione and its 17α-thioanalog. The key step in this pathway is thecis-cleavage of the 20-carboethoxyhydrazone of this epoxide by acetic and thioacetic acids and subsequent condensation of the products formed with acetone. This pathway is an efficient approach to the synthesis of the 16α,17α-dioxolane derivative and is equally efficient for preparation of the thioanalog, namely, 16α,17α-isopropylidenepregn-4-ene-9α,16α,21-triol-17α-thiol-3,20-dione, which has already been synthesized by an alternative method.

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-9α,16α,17α-triol-3,20-dione 16α,17α-acetonide (2) from 5α-H-pregn-16-en-3β-ol-20-one (1). The key stage in the proposed sequence of the reactions is the microbiological 9α-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.

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 16α,17α-isopropylidenedioxy-5α-pregnane-3Β,21-diol-20-one. It uses methods previously unused for 5α-H-steroids and involves 21-hydroxylation of 16α,17α-epoxy-5α-pregnan-3Β-ol-20-one with diacetoxyiodobenzene and cis-opening of the obtained 21-hydroxy-16α,17α-epoxy-5α-pregnane-3Β,21-diol-20-one by acetic acid in the presence of epoxycarbonylhydrazine, followed by condensation of the obtained product with acetone.

Approaches to the synthesis of 9α,21-dihydroxy-16α,17α-epoxypregn-4-ene-3,20-diones

Various approaches to the synthesis of 16α,17α-epoxypregn-4-ene-9α,21-diol-3,20-dione were studied. A preparative method was found for the synthesis of this compound by the microbiological transformations of 20,20-dimethoxy-16α,17α-epoxypregn-5-ene-3Β,21-diol using Rhodococcus sp. with subsequent removal of the dimethyl acetal protection in 20,20-dimethoxy-16α,17α-epoxypregn-4-ene-9α,21-dio-1-3-one.

Steroid transformations. Communication 169. Synthetic routes to 21-hydroxy(acetoxy)-2′,2′-dimethyl-[17α, l6α-d]-oxazolidine 20-ketosteroids

Conclusions21-Hydroxy(acetoxy)-2′,2′-dimethyl-[17α, 16α-d]-oxazolidines of 20-ketosteroids can be synthesized by two methods. One of these is based on the ammonolysis of 16α,17α-epoxypregn-5-en-3Β,21-diol-20-one 20-carbethoxyhydrazone and can have preparative value.

Transformed steroids. 172. Reaction of 16-methyl-20-ketosteroids with iodobenzene diacetate

Conclusions1.The reaction of 16-methylpregna-5,16-dien-3β-ol-20-one with iodobenzene diacetate in a methanolic alkali solution proceeds with a Favorskii rearrangement, with formation of 16-methylpregna-5, 16-dien-3β-ol-21-ic acid and its methyl ester.2.A new method for the synthesis of 21-hydroxy-16α,17α-epoxy-20-ketosteroids from 16β-methyl-16α,17α-epoxypregn-5-en- 3β-ol-20-one has been proposed.

Transformed steroids. 168. Reaction of 21-hydroxy(acetoxy)-16α,17α-epiminopregnenolone with pyridine thiocyanate

Conclusions1.A stereospecific cis opening of the aziridine ring of 20-carbethoxyhydrazone of 16α,17α-epiminopregn-5-en-3β,21-diol-20-one by thiocyanic acid and the synthesis of 21-hydroxy(acetoxy)-[17α,16α-d]-2′-imino-l′,3′-thiazolidine derivatives of 20-keto steroids were carried out.2.It was shown that the reactions of 3β,21-diacetoxy-16α,17α-epiminopregn-5-en-20-ones with thiocyanic acid in the presence of carbethoxyhydrazine are not straightforward processes.